How to calibrate instruments
Calibration hubs and step-by-step procedures for common instruments: thermometers, scales and balances, pressure gauges, torque wrenches and pipettes, each with the standards, tolerances and intervals that apply.
- InstrumentThermometerStart here →
- InstrumentScaleStart here →
- InstrumentPressure gaugeStart here →
- InstrumentTorque wrenchStart here →
- InstrumentPipetteStart here →
Pipette: types, ISO 8655 parts, error limits and calibration intervals
An overview of pipette calibration: pipette types, the parts of ISO 8655:2022, calibration vs routine testing, error limits, free guides and intervals. The gravimetric method step by step, with a calculator, is in our separate procedure.
- Pipette calibration: the ISO 8655 gravimetric method, step by stepHow to calibrate a pipette by the gravimetric method of ISO 8655-6:2022: the quick check vs a full calibration, what changed in 2022, balance and room requirements, test volumes and tips, the Z factor, systematic and random error, a worked example and a free calculator.
Pressure gauge: types, accuracy grades and calibration standards
An overview of pressure gauge calibration: gauge types, ASME B40.100 grades and EN 837-1 classes, the free DKD and EURAMET guidelines, reference standards, intervals and what NIST-traceable means for a gauge. The step-by-step method is in our separate procedure.
- Pressure gauge calibration: how to calibrate a pressure gauge (deadweight tester or comparator)How pressure gauge calibration works: what you can check yourself, how to choose between a deadweight tester and a comparator, test points up and down, hysteresis, mounting position, head and gravity corrections, accuracy grades, uncertainty and records.
Scale calibration: scale classes, standards, test weights and intervals
An overview of scale and balance calibration: scale accuracy classes, the EURAMET, NIST, OIML and USP documents that apply, which test weights match which scale, balance uncertainty and intervals. The step-by-step method is in our separate procedure.
- How to calibrate a scale: test weights, eccentricity, linearity and repeatabilityHow to calibrate a scale or balance: what the CAL button really does, how to choose test weights, the repeatability, error-of-indication and eccentricity tests, uncertainty, minimum weight and USP <41>, and how calibration differs from legal-for-trade verification.
Thermometer calibration: standards, accuracy limits and what NIST-traceable means
What thermometer calibration is, which standards and accuracy limits apply to each type of thermometer, and what a NIST-traceable thermometer really gives you. The step-by-step method is in our separate procedure.
- How to calibrate a thermometer: ice point, boiling point and comparison calibrationHow to calibrate a thermometer: the ice-point check done right, the boiling-water check corrected for altitude, what to do if it reads wrong, and the comparison procedure labs use, with test points, immersion, as-found and as-left results, uncertainty and records.
Torque wrench: types, ISO 6789 tolerances and calibration intervals
An overview of torque wrench calibration: wrench types and classes, the ISO 6789 and ASME B107.300 documents, permissible deviations, intervals and who calibrates the tester. The step-by-step method is in our separate procedure.
- Torque wrench calibration: how to calibrate a torque wrench (ISO 6789 procedure)How torque wrench calibration works: what you can check at home with a weight, and the ISO 6789 procedure labs use, with tolerances by wrench type, test points, readings, as-found and as-left results, uncertainty and calibration intervals.
Every instrument here follows the same logic: compare it with a reference several times more accurate, at points across the range you use, record the as-found result before any adjustment, and judge it against a stated tolerance with its uncertainty. What changes is the reference, the test points and the standard that sets them. Each hub gives the overview for one instrument (types, standards, tolerances and intervals) and links to a full procedure written from the free official guides. For the method behind all of them, see how to write a calibration procedure and what calibration is.