In the world of precision measurement, the terms "calibration" and "verification" are often used interchangeably. However, in industrial and regulated environments, understanding the distinction between these two concepts is critical for compliance, product quality, and traceability.
This article outlines the fundamental differences between calibration and verification, their roles in a quality management system, and when each is required in practice.
What is Calibration?
Calibration is the documented comparison of a measurement device (the unit under test) to a known reference standard, typically traceable to a national or international standard. The process involves:
Determining the accuracy of the device
Documenting the deviation (if any)
Optionally adjusting the instrument to bring it within specification
Issuing a calibration certificate with measurement uncertainty
Key Features of Calibration:
Performed by accredited calibration laboratories (e.g. ISO/IEC 17025)
Requires traceable reference standards
Provides documented uncertainty and compliance data
Typically scheduled at regular intervals (e.g. annually)
Example: A Fluke 87V Multimeter calibrated to ISO 17025 standards includes a certificate with measurement results, tolerances, and traceability.
What is Verification?
Verification is the process of checking that a measurement device or system meets predefined specifications or tolerances. It does not necessarily involve reference standards or adjustments.
Key Features of Verification:
Often performed in-house using known good equipment
Confirms whether the device is "fit for use"
May not produce formal calibration data
Does not provide traceable uncertainty
Example: A technician uses a reference weight to verify that a balance is reading within ±0.1 g before a routine production run.
Side-by-Side Comparison
Feature
Calibration
Verification
Traceability
Required to national/international standards
Not always required
Performed By
Accredited calibration labs
In-house technicians or QA staff
Adjustment Allowed
Yes
No
Measurement Uncertainty
Provided
Typically not provided
Documentation
Formal certificate with data
May be as simple as a checklist
Audit Compliance
Accepted by ISO 17025, FDA, etc.
Often insufficient for regulated audits
When Do You Need Calibration vs Verification?
Use Calibration When:
You require traceable documentation for audits (e.g. ISO, FDA, IATF)
You need to confirm the exact performance of the device
You are establishing or adjusting reference standards
Devices are used in critical measurements (e.g. torque tools, pressure sensors)
Use Verification When:
Performing quick quality checks between calibrations
Evaluating incoming goods or tools
Checking that equipment remains within tolerance during routine use
In many industries, both processes are used together to maintain operational integrity and minimize downtime.
Examples of Equipment Needing Calibration
Additel AM1760-20-SP Pressure Calibrator
Keysight DSOX1204G Oscilloscope
Mitutoyo 543-563A Digital Indicators
Torque Wrenches and Testers
High-precision Weighing Balances
Why This Distinction Matters
Confusing calibration with verification can lead to:
Audit nonconformance
Product recalls due to undetected measurement drift
Failure to meet customer or regulatory specs
Poor data reliability in research or validation environments
By clearly defining both processes in your quality management system, you ensure traceability, accountability, and robust compliance.
Best Practices
Maintain documented procedures for both calibration and verification
Use only ISO 17025-accredited labs for critical calibrations
Train staff to distinguish between the two activities
Schedule verification checks between full calibration cycles
Record verification results for traceability and trending
Conclusion
Calibration and verification are not interchangeable terms—they serve distinct but complementary roles in ensuring measurement confidence. Knowing when to calibrate and when to verify is essential for engineers, QA managers, and technicians striving to meet high-performance and regulatory standards.
At Jansen Calibration, we provide both accredited calibration services and consulting support to help you build a traceable, audit-ready measurement program.
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