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Torque wrench calibration certificate

Updated: October 2026

The sheet has a serial number and sometimes says calibration certificate. It came with a 3/8 inch click wrench. A torque wrench calibration certificate a workshop can file is a UKAS calibration to BS EN ISO 6789-2:2017. The paper in these cases is a declaration of conformance under Part 1 unless the sheet shows that UKAS work. The ranges are in the [3/8 inch torque wrench comparison](/hub/hand-tools/torque-wrench-3-8-inch). Hand movements stay on [how to use a torque wrench](/hub/hand-tools/torque-wrench-3-8-inch/sub/torque-wrench-3-8-inch-how-to-use). The Products Compared editorial team wrote this on 16 October 2026. We did not send these wrenches to a laboratory. If you buy through our links, we may earn a commission at no extra cost to you.

The sheet has a serial number and sometimes says calibration certificate. It came with a 3/8 inch click wrench. A torque wrench calibration certificate a workshop can file is a UKAS calibration to BS EN ISO 6789-2:2017.

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ATsafepro ATsafepro AT215B001 5–60 Nm

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ATsafepro ATsafepro AT215B001 5–60 Nm
8.6/10about £25.99
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Amazon Basics Amazon Basics DS-DTW-3 20.4–108.5 Nm

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8.5/10about £19.99
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Draper Draper 64534 10–80 Nm

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On this page
  1. 1.The sheet is a declaration unless it says UKAS
  2. 2.A printed ±3% is a claim, not a lab result
  3. 3.Twelve months is a quality-system default
  4. 4.No click means stop, then the shop

The sheet is a declaration unless it says UKAS

Part 1 of BS EN ISO 6789:2017 is the declaration of conformance for a new hand torque tool. Part 2 is calibration and uncertainty. Calibration Select, a UK firm, puts it this way: the paper with a new tool is now that declaration, and a Part 2 certificate adds uncertainty work a declaration does not. Bullets here still say calibration certificate or precision report. INGJER lists a precision report. SHINTOUR lists one with the manual. YIYEIE says a traceable certificate. None of those sheets has been shown to be UKAS. UKAS accreditation for a calibration laboratory sits on ISO/IEC 17025. A factory sheet with a serial number can be real and still not be UKAS. BMTA has noted that UK laboratories are not to issue a certificate of calibration against Part 1. If you need the Part 2 document, you buy the calibration. You do not assume it was folded into a £25 case. Model matching stays on the best 3/8 torque wrench page.

A printed ±3% is a claim, not a lab result

For usual click classes, the standard’s maximum permissible deviation is ±6% at a tool maximum of 10 N·m or below, and ±4% above that. A tighter claim such as ±3% has to be met if the maker prints it. It does not mean this comparison measured the wrench. Most 5–60 Nm and 5–70 Nm listings print ±3%. Amazon Basics prints ±4%. Draper 64534’s listing has no percentage. ss shovan’s bullet also names a GS mark. That mark is a seller claim. It is not a UK approval and it is not UKAS. Owner checks are not a laboratory result: one ATsafepro-set reviewer reported within 2%, and a 2017 Draper review found a certificate dated February 2015. Leave INGJER’s 60 Newton Millimeters, the set’s 0.5 g, and Draper’s 700 Foot Pounds and Cardboard as captured.
ATsafepro ATsafepro AT215B001 5–60 Nm

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ATsafepro ATsafepro AT215B001 5–60 Nm
8.6/10about £25.99
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Twelve months is a quality-system default

Norbar quotes 5,000 cycles or 12 months from the user’s first operation, not from the factory date, and a recalibration after an overload of 25% over maximum. That interval is not a household statute. A private owner is not breaking a law by missing the anniversary. PUWER 1998 applies when the wrench is work equipment. It is not the rule for a Saturday oil change at home. If you hung on the handle past the click, or used the wrench as a breaker bar, the 25% line is a reason to stop trusting the scale.

No click means stop, then the shop

Stop if there is no click. Do not finish the fastener by feel, and do not open the mechanism. If the goods are not of satisfactory quality, not as described, or not fit for purpose, the Consumer Rights Act 2015 gives a short-term right to reject within 30 days. A dead click on arrival can be that fault. It does not tell you what the sheet was. Call a professional for torque-plus-angle, a wheel or brake bolt already overtightened, or a signed uncertainty. A dearer row in the 3/8 inch torque wrench buying guide does not create a UKAS certificate.

Common questions

Is the sheet in the case a UKAS certificate?
Only if it is a UKAS calibration to BS EN ISO 6789-2. The paper with a new tool is a declaration under Part 1. Precision report and calibration certificate on these bullets have not been shown to be UKAS documents.
What is the difference between ISO 6789-1 and 6789-2?
Part 1 is the declaration for a new tool. Part 2 is the calibration and the uncertainty. A declaration can be valid and still omit that uncertainty. UKAS laboratory work is tied to ISO/IEC 17025, which is a different standard.
Does ±3% replace the standard’s ±4% or ±6%?
No. Usual click classes allow ±6% at 10 N·m or below, and ±4% above that. A printed ±3% is a tighter claim the maker has to meet. Amazon Basics prints ±4%. Draper’s listing prints no percentage. None of those lines is a test we ran.
How often should a private user recalibrate?
Norbar’s note is 5,000 cycles or 12 months from first use, and after a 25% overload. That is a quality-system default, not a law for a private garage. Recalibrate when you need a signed uncertainty, or when the wrench has been overloaded.
What if the wrench never clicks?
Stop. Do not keep pulling. Review samples here link a missing click to snapped fasteners. If it fails in the first 30 days and is not of satisfactory quality or not as described, the Consumer Rights Act gives a short-term right to reject. After 30 days the Act points to repair or replacement.
Does a GS mark mean it was calibrated in Britain?
No. ss shovan’s bullet names a GS mark beside ISO 6789-1. That is a seller claim. It is not UKAS, and it is not evidence of a calibration in the UK.
When do you need a signed uncertainty?
When the fastener is torque-plus-angle, when a wheel or brake bolt has already been overtightened, or when a workshop must file a calibration to BS EN ISO 6789-2. A box sheet from this set has not been shown to be that document.

Related pages

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Sources

Public UK and standards sources, plus the amazon.co.uk listings in this comparison. Page updated October 2026.

  1. ISO 6789-1:2017 (retrieved 16 October 2026)
  2. ISO 6789-2:2017 (retrieved 16 October 2026)
  3. Norbar: how often should I recalibrate my torque wrench (retrieved 16 October 2026)
  4. Norbar standard calibration terms (CL305) (retrieved 16 October 2026)
  5. Consumer Rights Act 2015, goods remedies (retrieved 16 October 2026)
  6. General Product Safety Regulations 2005 (retrieved 16 October 2026)
  7. HSE: PUWER overview (retrieved 16 October 2026)
  8. Cycling Weekly: torque wrench group test (retrieved 16 October 2026)