How do I check if a lab is UKAS accredited for my instrument?

Ask for the lab's UKAS schedule of accreditation and check that your specific parameter, range and, ideally, uncertainty are listed within its accredited scope. A lab can hold accreditation for some measurements but not others, so confirm that yours is covered — not just that the lab is 'UKAS accredited' in general.

What is the difference between accredited and traceable calibration?

Traceable calibration means the measurement links back through an unbroken chain to national standards. Accredited (UKAS ISO 17025) calibration adds independent assessment of the lab's competence and requires the certificate to state measurement uncertainty. Accredited calibration is traceable and independently verified; traceable-only calibration is not independently assessed.

What questions should I ask a calibration lab?

Ask: is my exact parameter and range within your UKAS accredited scope? What is your calibration and measurement capability (best uncertainty) for it? Do you calibrate on-site or in the lab? What is your turnaround time? Do you offer a recall reminder service? And will the certificate state traceability and uncertainty?

How to Choose a UKAS-Accredited Calibration Lab

Q: What does UKAS accreditation mean?

UKAS is the United Kingdom Accreditation Service, the national body that assesses calibration and testing laboratories against ISO/IEC 17025. UKAS accreditation means an independent authority has verified the lab's competence, methods and measurement capability for specific parameters and ranges — it is a much stronger assurance than a lab simply claiming to be 'ISO 9001 certified' or 'traceable'.

Choosing a calibration lab for regulated work comes down to one question that is easy to get wrong: is the lab actually UKAS-accredited for your specific instrument and range — not just accredited in general. Get that right and your certificates hold up; get it wrong and you may be paying for calibration that inspectors won't accept.

In shortUKAS accreditation means a lab's competence has been independently verified against ISO/IEC 17025. But accreditation is granted for specific parameters and ranges, listed in the lab's schedule of accreditation. Always confirm your parameter and range are in their accredited scope — and that the certificate will state traceability and measurement uncertainty.

Accredited, certified, traceable — not the same thing

UKAS accredited (ISO 17025): independently assessed competence for named measurements. The gold standard.
Traceable: the measurement links back to national standards — necessary, but not independently assessed on its own.
ISO 9001 certified: the lab has a quality management system. Useful, but it says nothing about technical calibration competence.

A lab may truthfully call itself "ISO 9001 certified" or "traceable" while not being accredited for your calibration. Read the words carefully.

UKAS accredited calibration certificate and scope

Check the schedule of accreditation

Every UKAS-accredited lab has a public schedule of accreditation listing exactly what it is accredited for: the parameters, the ranges, and its calibration and measurement capability (CMC) — the best uncertainty it can achieve. Confirm your parameter (e.g. temperature), your range (e.g. −30 to +40°C) and that its CMC is good enough for your needs. Accreditation for pressure or dimensional work does not cover temperature.

Questions worth asking

Is my exact parameter and range within your UKAS accredited scope?
What is your CMC (best uncertainty) for it — and is it small enough for my limits?
On-site or in-lab calibration? (On-site avoids downtime and transport risk.)
Turnaround time, and do you offer a calibration recall reminder service?
Will the certificate state traceability to national standards and measurement uncertainty?

Red flagsA lab that markets itself as "accredited" but can't show your parameter in its scope; a certificate with no measurement uncertainty; "traceable" used as if it means "accredited"; and a CMC so wide it can't actually judge your tolerance. Any of these should give you pause.

Frequently asked questions

What does UKAS accreditation mean?

Independent verification against ISO/IEC 17025 that a lab is competent for specific parameters and ranges — stronger than "ISO 9001 certified" or "traceable".

How do I check a lab is accredited for my instrument?

Check its UKAS schedule of accreditation and confirm your parameter, range and uncertainty are within its accredited scope.

Accredited vs traceable calibration?

Accredited is traceable plus independent assessment and stated uncertainty; traceable-only is not independently assessed.

What should I ask a lab?

Whether your parameter/range is in scope, their CMC, on-site vs lab, turnaround, recall service, and whether the certificate states traceability and uncertainty.

Key takeaways

UKAS accreditation is competence, independently verified — not the same as "certified" or "traceable".
Accreditation is scope-specific: confirm your parameter and range are covered.
Check the schedule of accreditation and the lab's CMC (best uncertainty).
Insist on a certificate that states traceability and measurement uncertainty.

Related guides

Get new guides by email

Practical monitoring, mapping and calibration guides, straight to your inbox. No spam — unsubscribe anytime.