FDA calibration requirements come from three places in Title 21 of the Code of Federal Regulations, and which one governs your program depends on what you make. Medical device manufacturers work under the Quality Management System Regulation at 21 CFR Part 820, which as of February 2, 2026, incorporates ISO 13485:2016 by reference and pulls calibration under Section 7.6 of that standard.1Food and Drug Administration. Quality Management System Regulation Frequently Asked Questions Pharmaceutical manufacturers follow Current Good Manufacturing Practice rules at 21 CFR Part 211, principally Sections 211.68 and 211.160(b)(4). Nonclinical laboratories operate under Good Laboratory Practice at 21 CFR Part 58, with calibration addressed in Section 58.63. The frameworks overlap in substance: every instrument that generates data affecting product quality needs a written calibration program, standards traceable to a national or international reference, a defined schedule, records that prove the work happened, and a documented response when equipment falls out of tolerance.
A company that makes both a device and a companion drug can end up complying with more than one framework at once. The requirements below are common across all three, with the citation you need noted where the frameworks diverge.
Written Procedures and Accuracy Limits
Every calibration program begins with a written procedure for each instrument. For pharmaceutical manufacturers, 21 CFR 211.160(b)(4) requires an established written program that spells out directions for performing each calibration, the acceptable limits for accuracy and precision, the calibration schedule, and what to do when equipment falls outside those limits. Equipment that fails to meet specifications cannot be used until it is brought back into compliance.2eCFR. 21 CFR 211.160 – General Requirements
Medical device manufacturers face parallel obligations under ISO 13485 Section 7.6: documented calibration procedures, recorded adjustments, and risk-based investigation when equipment fails to meet requirements. The prior 21 CFR 820.72 language, which the QMSR replaced, required specific directions and limits for accuracy and precision with provisions for remedial action and evaluation of any adverse effect on product quality.3eCFR. 21 CFR 820.72 – Inspection, Measuring, and Test Equipment
For GLP studies, 21 CFR 58.63 requires written standard operating procedures describing the methods, materials, and schedules for routine calibration, specifying remedial action when equipment malfunctions, and naming the person responsible for performing each calibration operation.4eCFR. 21 CFR 58.63 – Maintenance and Calibration of Equipment
Procedures should also address the environmental conditions under which calibration is performed. Temperature, humidity, vibration, and cleanliness can all compromise measurement accuracy, and the controls that hold those conditions stable need to be documented alongside the procedure itself.
Traceability to National or International Standards
Metrological traceability means your calibration standards connect through an unbroken chain of documented comparisons to a recognized national or international reference, typically a realization of the International System of Units.5National Institute of Standards and Technology. Metrological Traceability Frequently Asked Questions and NIST Policy In practice, this means your reference standards trace back to the National Institute of Standards and Technology or an equivalent international body.
The former 21 CFR 820.72(b)(1) stated the rule directly: calibration standards must be traceable to national or international standards. Where no such standard is practical or available, you must use an independent reproducible standard, and where no applicable standard exists at all, you must develop and maintain your own in-house standard.3eCFR. 21 CFR 820.72 – Inspection, Measuring, and Test Equipment ISO 13485 Section 7.6 carries the same hierarchy forward. NIST itself emphasizes that establishing and supporting a traceability claim is the responsibility of whoever provides the measurement result, not NIST.6National Institute of Standards and Technology. NIST Policy on Metrological Traceability
How Often to Calibrate
The FDA does not prescribe a universal interval. You must justify your calibration frequency based on the equipment’s historical stability, how heavily it gets used, the manufacturer’s recommendations, and the criticality of the measurements involved. For pharmaceutical operations, 21 CFR 211.68 requires that equipment be “routinely calibrated, inspected, or checked according to a written program designed to assure proper performance.”7eCFR. 21 CFR 211.68 – Automatic, Mechanical, and Electronic Equipment Section 211.160(b)(4) reinforces this with a requirement to calibrate “at suitable intervals” per the written program.2eCFR. 21 CFR 211.160 – General Requirements
Intervals are not set-and-forget. Review performance history and drift data periodically to decide whether the interval should shorten or can safely extend, and document the reasoning behind each interval and any change to it. An inspector who sees a 12-month interval for a critical gauge will ask why 12 and not 6 or 18.
Labeling Calibration Status
Every piece of calibrated equipment needs to display its calibration status where the people using it can see. Under the former 21 CFR 820.72(b)(2), device manufacturers had to document the equipment identification, calibration dates, the individual performing each calibration, and the next calibration date, with those records displayed on or near the equipment or readily available to users and calibration staff.3eCFR. 21 CFR 820.72 – Inspection, Measuring, and Test Equipment Most manufacturers meet this with a physical calibration sticker showing the last calibration date, the technician’s initials, and the next due date. Electronic tracking systems work as well, provided the information is available at the point of use.
Records and Retention
Incomplete or missing calibration records are among the most frequently cited observations on FDA Form 483s. At minimum, records must identify the specific equipment, the date of calibration, who performed it, and what standards were used. For medical devices, the prior 820.72(b)(2) required the equipment identification, calibration dates, the calibrating individual, and the next due date.3eCFR. 21 CFR 820.72 – Inspection, Measuring, and Test Equipment For pharmaceutical operations, 21 CFR 211.194(d) requires “complete records” of the periodic calibration of laboratory instruments, apparatus, gauges, and recording devices.8eCFR. 21 CFR Part 211 Subpart J – Records and Reports GLP records under 21 CFR 58.63(c) must include the date of each operation, note whether it was routine or nonroutine, and, for any repairs, document the nature of the defect, how it was discovered, and the remedial action taken.4eCFR. 21 CFR 58.63 – Maintenance and Calibration of Equipment
Recording “as found” readings before any adjustment and “as left” readings afterward is standard practice even where the regulations do not spell it out. Those two numbers are what you need if you later have to evaluate whether drift affected products made since the last calibration.
Retention runs by product type. Pharmaceutical calibration records fall under 21 CFR 211.180(a): production, control, and distribution records tied to a specific drug batch must be kept for at least one year after that batch’s expiration date.8eCFR. 21 CFR Part 211 Subpart J – Records and Reports For medical devices under the former QSR, quality system records were kept for the expected life of the device, with a minimum of two years from the date of commercial distribution. Under the QMSR, device manufacturers should consult ISO 13485 Section 4.2.5 along with any FDA-specific retention requirements still in effect.
When Equipment Fails Calibration
An out-of-tolerance finding is the highest-risk event in a calibration program, because it raises one question that has to be answered: did the inaccurate instrument affect any product made since its last successful calibration?
The prior 21 CFR 820.72(b) required medical device manufacturers to take remedial action to reestablish limits and to evaluate whether there was any adverse effect on device quality when accuracy and precision limits were not met.3eCFR. 21 CFR 820.72 – Inspection, Measuring, and Test Equipment For pharmaceutical manufacturers, 21 CFR 211.160(b)(4) requires “provisions for remedial action” when accuracy or precision limits are not met, and failed equipment must be taken out of service.2eCFR. 21 CFR 211.160 – General Requirements
The product impact assessment is the consequential part. Identify every batch or lot tested, measured, or manufactured with the out-of-tolerance instrument since its last passing calibration, then evaluate whether the degree of inaccuracy was enough to affect specifications. Sometimes the drift is small and product margins are wide, meaning no product is at risk. Other times the analysis shows released product may not meet specifications, which can trigger recalls. Root cause, corrective action, and effectiveness verification then feed the broader CAPA system, and inspectors will expect to see all of it in the record.
Software Validation for Calibration Systems
If you use computerized systems to schedule calibrations, store certificates, or perform automated calibrations, those systems must be validated. For medical devices, 21 CFR 820.70(i) requires manufacturers to validate computer software used as part of production or the quality system “for its intended use according to an established protocol,” and to validate all software changes before implementation. The FDA explicitly includes calibration management systems within scope, and all validation activities and results must be documented.1Food and Drug Administration. Quality Management System Regulation Frequently Asked Questions
For pharmaceutical manufacturers, 21 CFR 211.68(b) requires appropriate controls over computer systems so that changes to records are made only by authorized personnel and input and output data are checked for accuracy, with backup files maintained and protected from alteration or loss.7eCFR. 21 CFR 211.68 – Automatic, Mechanical, and Electronic Equipment Validation is not one and done. Any software upgrade, configuration change, or system migration needs to be revalidated before it goes live. A minor update to a calibration tracker can quietly break due-date calculations or record retrieval, and that usually gets caught by an inspector, not by the manufacturer.
Using Outside Calibration Providers
Many manufacturers send some or all of their calibration work to external laboratories. Outsourcing the work does not outsource the responsibility. You remain accountable for ensuring the provider meets the same standards your internal program would need to satisfy.
The industry standard for calibration laboratory competence is ISO/IEC 17025:2017. The FDA’s Accreditation Scheme for Conformity Assessment (ASCA) program uses ISO/IEC 17025:2017 as its baseline for recognizing laboratories that perform testing and calibration services for medical devices.9Food and Drug Administration. Testing Laboratories – How to Participate in ASCA Before engaging a provider, confirm that their accreditation scope covers the specific types of calibration you need. A laboratory accredited for dimensional measurements is not automatically qualified to calibrate temperature sensors.
The FDA maintains a database of ASCA-accredited testing laboratories where you can check a provider’s current status. Laboratories carrying an “FDA Initiated Withdrawal” status are ineligible and their reports are no longer accepted.9Food and Drug Administration. Testing Laboratories – How to Participate in ASCA Vendor qualification records should document the accreditation scope, the standards and methods covered, and any exclusions, and you should requalify the vendor and review performance on a defined cycle.
What Happens If the FDA Finds Gaps
When an investigator identifies a calibration problem, the first step is usually an FDA Form 483 listing the observations. Common calibration-related findings include absent written procedures, missing or incomplete records, instruments used past their calibration due dates, and programs that lack specific accuracy and precision limits or remedial action provisions.
If the problems are not adequately addressed, the FDA can escalate to a warning letter requiring a formal written response with a corrective action plan. Persistent or severe violations, particularly those suggesting a pattern of ignoring calibration requirements, can lead to an injunction. An FDA injunction is a court order that can force a company to stop interstate shipment of products manufactured under the violative conditions, and for a company employing hundreds of people the impact of a shutdown order can be severe. An inspector who finds expired stickers, missing records, or no written procedure will read that as evidence the wider quality system has gaps, and the scope of the inspection tends to expand accordingly.