Calibration is an essential procedure that involves the adjustment and validation of measurement instruments to guarantee their accuracy and consistency in providing dependable results. This practice holds immense significance across diverse sectors including manufacturing, healthcare, research, and others. In the absence of meticulous calibration, errors can permeate throughout operations, resulting in subpar outcomes, escalated expenses, and compromised quality.


In today’s ever-changing business environment, precision and accuracy are essential elements for achieving success. Whether you are involved in the production of advanced technology or carrying out scientific research, the dependability of your measurements is crucial. This is where the Calibration Master Plan becomes indispensable – a strategic blueprint that acts as the foundation for guaranteeing the precision and reliability of measurement instruments. In this discussion, we will examine the importance of a Calibration Master Plan and examine its fundamental constituents.


The process of calibration involves the adjustment and verification of measurement instruments to guarantee their accuracy and consistency in providing reliable results. It holds immense importance in diverse sectors including manufacturing, healthcare, research, and others. In the absence of appropriate calibration, errors can permeate throughout operations, resulting in subpar outcomes, escalated expenses, and compromised quality.


The Calibration Master Plan is written to provide an approach to calibration management. Calibration of the Instrument is a prerequisite for the initial qualification and ongoing performance of any equipment or system. Therefore it is necessary to check the instruments for their calibration during the installation of equipment or system and further re-calibration at a prescribed frequency.

The Calibration Master Plan:

The process of calibration involves the adjustment and verification of measurement instruments to guarantee their accuracy and consistency in providing reliable results. It holds immense importance in diverse sectors including manufacturing, healthcare, research, and others. In the absence of appropriate calibration, errors can permeate throughout operations, resulting in subpar outcomes, escalated expenses, and compromised quality.

Scope and Objectives: Clearly define the scope and objectives of the Calibration Master Plan. This includes identifying the types of instruments covered, the frequency of calibration, and the desired level of accuracy.

Inventory of Instruments: Develop a detailed inventory of all measurement instruments within the organization. This includes equipment used in production, testing, and quality control processes. Categorize instruments based on criticality and establish priorities for calibration.

Calibration Procedures: Document standardized calibration procedures for each type of instrument. These procedures should be detailed, step-by-step guides that outline the methods and equipment used for calibration. Having standardized procedures ensures consistency and reliability across calibration activities.

Frequency of Calibration: Establish a calibration frequency for each type of instrument based on industry standards, manufacturer recommendations, and the criticality of the instrument’s role in the processes. Regular calibration schedules prevent drift in measurement accuracy over time.

Responsibilities and Roles: Clearly define the roles and responsibilities of individuals involved in the calibration process. This includes personnel responsible for performing calibrations, managing the calibration schedule, and maintaining calibration records.

Documentation and Record-Keeping: Implement a robust system for documenting calibration activities and maintaining calibration records. Accurate record-keeping is essential for tracking the history of each instrument, demonstrating compliance with regulations, and identifying trends in instrument performance.

Training and Competency: Ensure that personnel involved in calibration activities are adequately trained and possess the necessary competencies. Training programs should cover both theoretical knowledge and practical skills related to calibration procedures.

Audit and Compliance: Regularly audit the calibration processes to ensure compliance with the Calibration Master Plan. This involves assessing the accuracy of instruments, reviewing documentation, and identifying opportunities for continuous improvement.

Key Calibration Requirements

The Calibration Master Plan shall address the Calibration requirements of the critical instruments based on impact assessment for the product quality.  The impact assessment is the process of evaluating the impact of operating, controlling, alarming, and failure conditions of a system on the quality of a product.  Depending on the facility and resources available the Instruments are categorized as Internal (In-House) & External Calibration. From these both categories, The Instruments shall be further classified as critical, and non-critical Instruments.

A critical instrument is an instrument within an equipment/system where the operation, contact, data, control, alarm, or failure may have a direct impact on the quality of a product.

Applicability of any of the following criteria to a given instrument/component will indicate that the component is critical.

The instrument/component controls the critical processes that may affect product quality.

The instrument/component is used to monitor the parameters of the manufacturing process.

Failure or alarm of the instrument/component will have a direct impact on product quality.

A non-critical instrument is an instrument within an equipment/system where the operation, contact, data, control, alarm, or failure will have an indirect impact or no impact on the quality of the product.

The following statements are related to critical / non-critical instruments, they outline the regulatory requirements for a successfully managed instrument calibration program,

All instrumentation shall be assigned a unique number and all critical/non-critical products, processes, and other instruments should be physically tagged.

The calibration method shall be defined by Standard Operating Procedures. if having the in-house resources for calibration otherwise all instruments shall be calibrated by an external agency

There shall be a means of readily determining the calibration status of each instrument.

Each measuring standard shall be traceable to a nationally, or internationally, recognized standard, as well as external or in-house calibration.

Periodic Review

The Calibration Master Plan shall be reviewed once in one year to ensure compliance and to determine whether a change is required due to the following reasons.

Changes in the Calibration Approach

Changes in Key Calibration Requirements.

Modification or renovation of the existing facility.

Calibration Policy

The Calibration Program is typically applied to Instruments/components of all equipment/systems within the Facility, regardless of the impact on the product quality.  Components, that have been determined to be critical to product quality, will have more frequent calibration schedules.

The calibration of the critical instruments will be verified in IQ (or as a pre-requisite of OQ) before undergoing qualification testing, to ensure that the test results are valid.  This verification, along with the calibration certificates and procedures, provides the documented evidence required to demonstrate that a system operates in a controlled state.

The calibration of instruments attached to the process, testing, and utility equipment shall be undertaken by the Engineering Department as a part of the Calibration exercise. The instruments to be calibrated shall be identified and calibrated during the IQ stage. The specific parameters to test, as well as the relevant specifications, shall be defined in the Standard Operating Procedure for the instruments.

After completion of the operational qualification, the recalibration of the Instrument shall continue at the predefined frequency as per the respective Standard Operating Procedures for Instrument Calibration or as per the calibration calendar.

However, there are instruments at the location that don’t have links with IQ / OQ documents, which will be covered under the calibration calendar.

Procedure for Criticality Assessment of Instrument

All instruments directly, or indirectly, involved with the process shall be individually assessed for their criticality to the process. The annual calibration calendar of all the instrumentation about each equipment or system shall be listed and uniquely identified.

Once identified, further details shall be added to the schedule including measurement range, location, and any other information, which is necessary.

Criticality Assessment Team (CAT)

The representatives of the following disciplines shall represent the CAT:

Engineering / Instrumentation

Quality Assurance


The manufacturing person shall sign the Calibration calendar to accept that the specification of the listed instrument and its limits are appropriate to the related product and process.


The Engineering representative shall confirm that all instruments are recorded and scheduled for calibration appropriately, as defined within the Calibration calendar. The engineering representative shall sign the Calibration calendar to qualify that the specification of the listed instrument and its limits have been defined and checked as appropriate to the related product and process.

Quality Assurance

The QA representative shall also sign the Calibration calendar to qualify that the specification of the listed instrument and its limits are appropriate to the related product and process.  QA has the final signature to approve the Calibration calendar fit for use. The QA representative shall verify that all calibration records and procedures are maintained and updated.

Ranges and Limits

While deciding on calibration ranges and limits, the manufacturer’s accuracy and process requirements shall be taken into account.  For example, an instrument would normally be calibrated across its operating or full range.

Calibration Accuracy:  The agreed specific working accuracy of the instrument.

This is usually set at the manufacturer’s accuracy but could be relaxed or increased to reflect the process requirements.

Calibration Failure Limits:  The limits set for instrument failure, as determined by the process requirements or results go beyond the acceptance criteria.

If the calibration failure limits are exceeded then a possible non-conformance has occurred, and the response should be documented.

Calibration Acceptance Limits:      The limits set for instrument Acceptance

If the readings go beyond calibration acceptance limits then a possible non-conformance has occurred, and the response should be documented.


The periodicity of calibration shall be based on the Category of instrument Critical instrument, Non-Critical Instrument.

In-house calibration

The frequency of calibration is once a year for non-critical Instruments & once in a half year for critical Instruments or as defined in the respective sop of the instruments.

External agency calibration

The frequency of calibration is once a year for non-critical Instruments & once a half a year for critical Instruments or as defined in the respective sop of the instruments.

Change Related to Calibration

There are circumstances where instrument criticality and its associated calibration details may change regularly, such as in multi-purpose plants.

Any change to the instrument Calibration Calendar, SOP, and frequency of calibration shall be documented in support of these amendments as a part of the change management procedure.

Guidance for the method of Instrument Calibration

The instrument shall be calibrated against reference standards as per SOP.  Reference standards shall be calibrated to or traceable to any national standard. Calibration of the reference standard shall be carried out in NPL or NABL-accredited laboratories. Calibration of the instrument and reference instrument shall be carried out at a predetermined frequency. Instruments are checked for its calibration throughout their operating range. The instrument is considered calibrated when the output of the instrument is within the acceptable range of deviation from the expected output. If the test of calibration shows a deviation more than the acceptable range, the instrument is replaced or subjected to maintenance. After maintenance, it is again calibrated prior to use.

The instruments, which cannot be calibrated in-house due to the unavailability of the facility & Resources, are sent for calibration to an outside calibrating agency.

Life Cycle Phases

The life cycle of an instrument can be split into three distinct phases:

Phase 1   > Project Phase

Phase 2   > Operational Phase

Phase 3   >  Periodic Recalibration

Project Phase

The new instruments which are part of a new project or new equipment will have the following stages.

  1. Responsibilities
  2. Specification of the instrument
  3. Labelling
  4. Calibration Process
  5. Installation Qualification sign off

It is not essential that bench calibrations are performed at IQ stage.  The purpose of bench calibrations is to ensure that instruments delivered from manufacturers are not damaged and are working.  This is a commercial requirement to ensure no delays in the project occur.

If bench calibrations are performed, the party’s supplier’s calibration certificate shall be readily used.

The Installation Qualification (IQ) shall be signed off before progression to the next stage. The calibration certificate shall be tied along with the IQ document.

Operational Phase

Standard Operating Procedures (SOPs) shall be established and at this point, the information shall be entered on to the Maintenance Management Systems. All instruments shall have calibration certificates at the Pre-Operational phase before moving to the Operational Phase. On completion, a check shall be made to ensure that the relevant documentation is correct and the current status of the equipment is clear.

Periodic Re-calibration

The periodic recalibration of the instrument shall be done as per the frequency mentioned below.

In-house calibration

The frequency of calibration is once a year for non-critical Instruments & once a half a year for critical Instruments or as defined in the respective sop of the instruments.

External agency calibration

The frequency of calibration is once a year for non-critical Instruments & once half a year for critical Instruments or as defined in the annual calibration calendar.

Equipment/Instruments requiring scheduled calibration will have a standard grace period. As given below:

Annual calibrations will have a grace period of ±14 days.

Half-yearly calibrations will have a grace period of ±10 days.

Quarterly calibration will have a grace period of ±7 days.

Monthly calibration will have a grace period of ±4 days.

Daily calibration will have no grace period and should be done on every working day.

Key Requirements

While carrying out calibrations the following shall be considered:

The calibration should be performed under optimum / required ranges.

The test equipment is traceable to accepted national standards.

Calibration Process

Specification of the Instrument

There is a very large range of instruments available in the market that makes selection difficult, and simply relying on the high-accuracy claims of a manufacturer is not the answer.  There are other important factors and influences to consider, which shall be taken into account before any decisions are made, including:

  • Accumulative errors due to non-linearity
  • Hysteresis
  • Temperature effects
  • Repeatability

Important questions to consider include:

  • What does the instrumentation have to do?
  • What are the required calibration failure limits and across what range?

An instrument can then be selected which shall, ideally, be at least two times more accurate than the process requirements.


The range of an instrument shall not exceed the required operating range.  Where an instrument is used for more than one process, it may be necessary to set a larger range so that it exceeds the process requirements.  It is also a regulatory expectation that at least one test point is within the operating range of an instrument used in a product-critical application and it is, therefore, vital that the operating range is defined.


Once the required Acceptance limit for measurement has been defined in the criticality assessment process, the instrument details shall be checked to ensure that it is capable of meeting that requirement consistently and without deviation that would fail two calibrations.


A non-conformance investigation shall be conducted when a critical instrument has failed to meet the acceptance criteria for the calibration.

If the ‘as found” results indicate that the instrument is outside the calibration limits, then the following actions are taken:

  1. Previous calibration labels shall be removed, where applicable.
  2. An ‘out of calibration’ label shall be attached.
  3. A non-conformance report shall be raised for all failed critical instruments.
  4. The action to repair, adjust, or replace the instrument shall be followed.
  5. The impact study shall be done as per the current version of the SOP on corrective and preventive action.

In the event of non-conformance, based on the impact study, the QA department shall be informed to recall approved/dispatched products.

Third-Party Calibration

Calibration may be carried out by third parties (e.g., contractors or instrument suppliers), but the responsibility for ensuring that calibration procedures have been correctly followed shall remain with the instrument owner (i.e., the equipment user and the maintenance Personnel)

The competence of the contractors (the Contract Acceptors) shall maintain suitable premises, equipment, knowledge, experienced, and competent personnel, and may not pass to a sub-contractor any of the work entrusted to him, nor change any of the agreed tests, standards, or limits, without the Contract Giver’s prior evaluation and approval.

There shall be a written contract with the Contract Acceptor and any technical arrangements made concerning it.  This contract shall include:

  1. Specify the respective responsibilities of the Contract Giver and Contract Acceptor.
  2. Describe (or reference) the tests to be done and the standards and limits to be applied.
  3. Specify the documentation to be used, produced, and retained by the Contract Acceptor, and to be supplied by the Contract Giver.
  4. Describe any hazards associated with the use or testing of the item(s)
  5. Be drawn up with the involvement of suitably qualified and experienced Personnel
  6. Sharing of information of any change (s) done at the contract acceptor’s end.

Documentation, supplied by the Contract Acceptor to the Contract Giver on completion of calibration, shall identify the item(s) concerned, show the initial test results, indicate any adjustments made, and (where relevant) the test results after adjustment.

When the Contract Giver receives the item(s) returned from the Contract Acceptor, the item(s) should be carefully examined for possible damage in transit.  An appropriately qualified and trained person should review and approve the given by the Contract Acceptor.

Technical Agreement:  Make a Technical Agreement with the contract Acceptor and furnish the following details of the Instruments to the calibration agency.

  1. Name of the instrument
  2. Make of the instrument
  3. Instrument Identification Number
  4. Acceptance Limit.
  5. Range

After receiving the calibrated Instruments from the Contract Acceptor or after the calibration of an instrument at our location ensure/check the following details.

  1. Date of calibration.
  2. The reference standard used for calibration & its traceability with national/international standards
  3. Calibration results & error with remarks, if any
  4. Next due for calibration.


It is a minimum requirement that all products, processes, and Utility instruments are uniquely labeled. This Guide recommends that for critical /non-critical instruments Calibration tag shall detail the next calibration due date.

Function: Labelling of Instrument will be performed to serve the following functions:

– Alert the user to its calibration and operating status.

– Show that the instrument is part of the inventory and scheduling system.

– Demonstrate that each piece of Instrument has been studied regarding its need for calibration or maintenance.

Location: Where practical, all Calibration status tags will be placed in a prominent place on the instrument. This alerts the user of its calibration status.

Types of labels. The different types of labels that will be used are:

Calibration Tag: These labels are placed on instruments calibrated, as required, periodically.

Under Maintenance: These labels indicate that the instrument is under maintenance and cannot be used.

Daily Calibration: These labels indicate that the calibration is done daily and respective entries are made on the logbook.

Calibration label for the external agency: Place the tag given by the external agency in case the external agency cannot provide it, the calibration Status tag should be as per the detail mentioned by the certificate.


Calibration Records

Calibration records shall demonstrate the capability of a measuring instrument or system to measure a variable to a required accuracy over a specific range of values. The calibration record, including the prime data, shall be unambiguous and retrievable. Handwritten data should be in pen, with mistakes crossed out with a single line. The amended data should be signed and dated. Calibration information shall be recorded on the calibration certificate to enable the calibration to be reproduced under similar conditions.

Calibration calendar: The calibration calendar is prepared with the calendar content of Instruments with calibration Due Dates & location / Machine at which the Instrument has been installed. The periodicity of recalibration shall be based on the category of the Critical instrument and non-critical Instrument.

Certificate of Calibration – Certificates of calibration shall contain:

  • Unique identification of the instrument under test
  • The ‘as found’ readings and, if adjusted, the ‘as left’ readings
  • The date of the calibration
  • Name of the person carrying out the calibration.
  • Due Date of calibration
  • Reference SOP Number.
  • Due Date/Validity of Calibration for Master Instruments
  • Calibration certificate no of Master Instruments.


7.0       Definitions:

Appropriately Trained Personnel: Persons who have been trained and their competence assessed to a suitable level of expertise to carry out defined activities.

Calibration: The set of operations, that establish, under specified conditions, the relationship between values indicated by a measuring instrument or measuring system, or values represented by a material measure, and the corresponding known values of a reference standard.

Calibration Accuracy: The agreed-specified working accuracy of the instrument.

Calibration Acceptance Limits: The limits set for instrument Acceptance, as determined by the process requirements.

Calibration Periodicity: Frequency of scheduled calibrations.

Calibration Range: Specified range over which the instrument is calibrated.  This should be greater than the process range.

Calibration Report: Document summarizing the results of calibration activity.

Calibration Status: Indication of instrument compliance at a fixed point in time.

Change Control: Documented process for the control of change that is traceable.

Contract Giver: Person(s) responsible for awarding calibration contracts to third-party contractors (Contact Acceptor).

Contract Acceptor: The third party carrying out the contract on behalf of the Contract Giver.

Customer: A recipient of a product provided by the supplier.

Installation Qualification (IQ): Establishing documented evidence that the key aspects of the purchased item or installation conform to approved written specifications and/or drawings.

Instrument: Device or devices used to carry out a measurement.

Instrument Loop: A group of instruments connected to monitor, or control, a process variable.

National Standard: Reference standard for a particular country or community, traceable to a specific reference.

Non-Critical: An instrument whose failure is deemed to not affect product quality, process/system performance, safety, or the environment.

Non-Conformance: A deviation from defined procedures.  Failure to meet defined criteria may also be referred to as an exception or deviation report.

Primary Element: Device used to convert the process parameter into a measured signal.

Critical Instrument: A process/system critical instrument is an instrument whose failure may have a direct effect on process or system performance without affecting final product quality, or safety.

Process Limits: Extent of the process range

Process Range: Specified range within which the process should operate.

Product Contact Parts: A part used for a qualified item of equipment or system that is in direct contact

Qualification: The process of demonstrating whether an entity is capable of fulfilling specified requirements.

Qualification Protocol: A Plan for use in Qualification activities

Supplier: Any organization or individual contracted directly by the customer to supply a product or service.

Test Equipment: Instrument or device used to calibrate other instruments, which is traceable back to accepted national standards.  The test equipment should have precision, accuracy, and repeatability that is higher than that of the instrument being calibrated.

Validation: The action of proving, by the principles of GMP, that any procedure, process, equipment material, activity, or system leads to the expected results.  See also Qualification.

Validation Master Plan: A quality Plan for a project with validation requirements, which describes the overall strategy for validating a system within its operating environment, seen from the user’s perspective.  Sometimes called a Validation Plan or a Validation Master Plan.  See also Quality Plan.

Validation Protocol: A Test Plan for use in Validation activities.

Verification: Confirmation by examination and provision of objective evidence that specified requirements have been fulfilled.  Verification is confirmation for a particular use whereas Validation is confirmation for a more general and intended use.

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About Pharmaceutical Guidanace

Ms. Abha Maurya is the Author and founder of pharmaceutical guidance, he is a pharmaceutical Professional from India having more than 18 years of rich experience in pharmaceutical field. During his career, he work in quality assurance department with multinational company’s i.e Zydus Cadila Ltd, Unichem Laboratories Ltd, Indoco remedies Ltd, Panacea Biotec Ltd, Nectar life Science Ltd. During his experience, he face may regulatory Audit i.e. USFDA, MHRA, ANVISA, MCC, TGA, EU –GMP, WHO –Geneva, ISO 9001-2008 and many ROW Regularities Audit i.e.Uganda,Kenya, Tanzania, Zimbabwe. He is currently leading a regulatory pharmaceutical company as a head Quality. You can join him by Email, Facebook, Google+, Twitter and YouTube

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