Torque Wrench Calibration: Standards, Intervals and Why It Matters

A torque wrench is only useful if you can trust the number it gives you. Over time, springs weaken and mechanisms wear, and a wrench that once clicked at 100 Nm may be over- or under-tightening critical fasteners. Torque calibration restores that trust — and documents it. Here is what you need to know.

Why torque calibration matters

Under-torqued bolts work loose; over-torqued bolts stretch, strip or fail. On safety-critical joints — automotive wheels, aerospace fasteners, structural steel, rail — the consequences are serious, and auditors know it. A calibrated torque tool with a traceable certificate is your evidence that the joint was tightened correctly.

The standard: ISO 6789

ISO 6789 is the international standard for the calibration of hand torque tools — click wrenches, beam and dial wrenches, torque screwdrivers and multipliers. It defines how the tool is tested across its range and the tolerances it must meet. Calibrating to ISO 6789 means your certificate is comparable, defensible and recognised.

How often should torque tools be calibrated?

ISO 6789 recommends recalibration every 12 months or every 5,000 operations, whichever comes first. In practice:

• General workshop tools — annually.
• Safety-critical assembly (aerospace, structural, rail) — every 6 months or 5,000 cycles.
• High-volume production tools — quarterly, or driven by your process data.

Also recalibrate any tool that has been dropped, overloaded or stored for a long period before its next critical use.

What a torque calibration involves

A proper torque calibration is more than a single check. We measure the tool against a traceable torque transducer at multiple points across its range — typically 20{ba9c0d8d78c6fccc70893e8a864d68467529f0286770abfe273019ba4716b247}, 60{ba9c0d8d78c6fccc70893e8a864d68467529f0286770abfe273019ba4716b247} and 100{ba9c0d8d78c6fccc70893e8a864d68467529f0286770abfe273019ba4716b247} of full scale — and in both directions where relevant. You receive:

• As-found readings (how the tool performed before adjustment) and as-left readings (after).
• Measurement uncertainty and a clear pass/fail against tolerance.
• A NATA-traceable certificate and a tag showing the next due date.

The as-found data is important: it tells you whether work done since the last calibration was within tolerance.

On-site torque calibration

Our mobile units carry traceable torque transducers and analysers, so we can calibrate a whole toolroom or production line at your site — no shipping tools interstate and no waiting. That matters most when a line can’t spare its tools, or when a customer audit or PPAP needs current certificates on a fixed date.

Frequently asked questions

Is FWC’s torque calibration NATA-traceable?
Yes. FWC Calibration is not itself NATA-accredited, but our torque calibrations are NATA-traceable — the torque reference standards we use are calibrated by NATA-accredited laboratories, and we align our procedures with ISO 6789 under an ISO 9001:2015 quality system.

Do you calibrate torque wrenches on-site?
Yes — wrenches, screwdrivers, multipliers and transducers, at your facility across NSW, ACT, VIC and NT.

Can I get a certificate for an audit?
Every torque calibration comes with a traceable PDF certificate showing as-found/as-left readings, uncertainty and pass/fail — ready for ISO 9001, IATF 16949, AS9100 or customer PPAP audits.

Get your torque tools calibrated

Tell us the make, model, torque range and quantity, and whether you need on-site or lab, and we will quote within one business day. See our torque calibration and mechanical calibration services, or get a quote — call 0409 663 566.

Related guides

• NATA-traceable vs NATA-accredited calibration
• How often should you calibrate?
• Torque calibration service

Browse all our calibration guides and resources, or see the full range of calibration services.