How often should your instruments be calibrated?
Typical starting intervals for 68 common measuring instrument types, with the range seen in practice. Each guide covers the relevant standards, what shortens or lengthens the interval, a procedure outline and the sources behind every claim.
Calibration intervals are a risk-based decision for the instrument owner: guidance documents such as ILAC-G24 and OIML D 10 describe how to set and adjust them. Use these numbers as starting points, not compliance requirements.
The full dataset behind these guides, all 68 types with sources, is published as an open CC BY 4.0 dataset: the calibration interval reference, with CSV and JSON downloads.
New to the job? Start here
Inheriting a calibration spreadsheet
A triage plan for the register you just took over from someone who left.
Setting up a system from scratch
The 10-step plan for standing up a calibration program where none exists.
What auditors ask about calibration
The real audit questions, in auditors' own words, and what answers them.
Dimensional
| Instrument | Typical | In practice |
|---|---|---|
| Bore Gauge | 12 mo | 3-24 mo |
| Caliper | 12 mo | 3-24 mo |
| Coating Thickness Gauge | 12 mo | 6-24 mo |
| Coordinate Measuring Machine (CMM) | 12 mo | 6-24 mo |
| Depth Gauge | 12 mo | 3-24 mo |
| Dial Indicator | 12 mo | 1-24 mo |
| Dial Test Indicator | 12 mo | 1-24 mo |
| Extensometer | 12 mo | 6-18 mo |
| Feeler Gauge | 12 mo | 6-12 mo |
| Gauge Block | 12 mo | 6-24 mo |
| Height Gauge | 12 mo | 3-24 mo |
| Micrometer | 12 mo | 3-24 mo |
| Optical Comparator | 12 mo | 6-36 mo |
| Plug Gauge | 12 mo | 3-24 mo |
| Radius Gauge | 24 mo | 12-60 mo |
| Ring Gauge | 12 mo | 6-12 mo |
| Snap Gauge | 12 mo | 3-24 mo |
| Steel Rule | 12 mo | 6-24 mo |
| Surface Plate | 12 mo | 6-36 mo |
| Surface Roughness Tester | 12 mo | 6-24 mo |
| Tape Measure | 12 mo | 6-36 mo |
| Thread Gauge | 12 mo | 3-24 mo |
| Ultrasonic Thickness Gauge | 12 mo | 6-24 mo |
Force / torque
| Instrument | Typical | In practice |
|---|---|---|
| Force Gauge | 12 mo | 3-12 mo |
| Load Cell | 12 mo | 6-26 mo |
| Torque Tester | 12 mo | 6-12 mo |
| Torque Wrench | 12 mo | 6-12 mo |
| Universal Testing Machine | 12 mo | 6-12 mo |
Hardness
| Instrument | Typical | In practice |
|---|---|---|
| Durometer | 12 mo | 6-12 mo |
| Hardness Tester | 12 mo | 12-18 mo |
Pressure / vacuum
| Instrument | Typical | In practice |
|---|---|---|
| Barometer | 12 mo | 6-24 mo |
| Differential Pressure Gauge | 12 mo | 6-24 mo |
| Manometer | 12 mo | 3-24 mo |
| Pressure Gauge | 12 mo | 3-24 mo |
| Pressure Transmitter | 12 mo | 3-60 mo |
| Vacuum Gauge | 12 mo | 6-12 mo |
Temperature / humidity
| Instrument | Typical | In practice |
|---|---|---|
| Digital Thermometer | 12 mo | 6-24 mo |
| Hygrometer | 12 mo | 6-24 mo |
| Infrared Thermometer | 12 mo | 6-24 mo |
| Liquid-in-Glass Thermometer | 12 mo | 6-24 mo |
| Resistance Temperature Detector (RTD) | 12 mo | 6-24 mo |
| Temperature Data Logger | 12 mo | 6-24 mo |
| Thermal Imager | 12 mo | 6-24 mo |
| Thermocouple | 12 mo | 1-24 mo |
Electrical
| Instrument | Typical | In practice |
|---|---|---|
| Clamp Meter | 12 mo | 6-24 mo |
| Digital Multimeter | 12 mo | 6-24 mo |
| Insulation Resistance Tester | 12 mo | 6-24 mo |
| LCR Meter | 12 mo | 6-24 mo |
| Oscilloscope | 12 mo | 6-24 mo |
Mass / volume
| Instrument | Typical | In practice |
|---|---|---|
| Analytical Balance | 12 mo | 6-12 mo |
| Calibration Weights | 12 mo | 6-24 mo |
| Hydrometer | 24 mo | 12-36 mo |
| Industrial Scale | 12 mo | 1-12 mo |
| Pipette | 12 mo | 3-12 mo |
Flow
| Instrument | Typical | In practice |
|---|---|---|
| Anemometer | 12 mo | 6-24 mo |
| Flow Meter | 12 mo | 6-24 mo |
Time / frequency
| Instrument | Typical | In practice |
|---|---|---|
| Stopwatch | 12 mo | 12-24 mo |
| Stroboscope | 12 mo | 12-24 mo |
| Tachometer | 12 mo | 12-24 mo |
Optical / light
| Instrument | Typical | In practice |
|---|---|---|
| Lux Meter | 12 mo | 3-24 mo |
Acoustic / vibration
| Instrument | Typical | In practice |
|---|---|---|
| Accelerometer | 12 mo | 3-24 mo |
| Sound Level Meter | 12 mo | 12-24 mo |
| Vibration Meter | 12 mo | 6-24 mo |
Chemical / analytical
| Instrument | Typical | In practice |
|---|---|---|
| Conductivity Meter | 12 mo | 6-12 mo |
| Gas Detector | 6 mo | 3-12 mo |
| Moisture Meter | 12 mo | 6-24 mo |
| pH Meter | 12 mo | 6-12 mo |
| Refractometer | 12 mo | 6-12 mo |
The interval is the easy part. Keeping 200 of them is not.
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