Calibration Resources
Accredited vs Non-Accredited Calibration: What Your Auditor Actually Checks
The difference between accredited and non-accredited calibration is independent assurance: an accredited (ISO/IEC 17025) calibration has had its methods, traceability and measurement uncertainty assessed by a national body, while a non-accredited calibration produces a certificate with no third party vouching for it. To an auditor, that distinction decides whether your certificate counts as evidence.
What "accredited" actually means
In Singapore, accreditation is granted by SAC-SINGLAS against ISO/IEC 17025. It confirms the laboratory is technically competent, that its measurements are traceable through an unbroken chain to national standards, and that each result carries a stated measurement uncertainty. See our accreditation and scope.
What your auditor checks on the certificate
- The accreditation mark & number — is the certificate issued under a recognised accreditation, and is the discipline within the lab's scope?
- Traceability — can the measurement be traced to national/international standards?
- Measurement uncertainty — is an uncertainty stated for each result (not just a pass/fail)?
- As-found / as-left data — what condition was the instrument in when it arrived, and after adjustment?
- Identification & date — is the exact instrument identified, with calibration and due dates?
When non-accredited is fine — and when it isn't
For non-critical, indicative measurements, a non-accredited calibration may be acceptable. But where the measurement affects product quality, safety, trade or a regulated process, an accredited certificate is what holds up under scrutiny. The mistake we see most often is discovering — mid-audit — that a "calibrated" instrument has no traceable, accredited backing.
How to stay audit-ready
Keep accredited certificates for your critical instruments, track due dates, and confirm the calibrated discipline sits within the lab's accredited scope. Unitest issues accredited certificates and sends recall reminders so nothing lapses. Need a refresher on accreditation itself? Read what SAC-SINGLAS accreditation means for your audit.
Get audit-ready calibration
Request an accredited calibration quote or explore our calibration services.
Frequently asked questions
What is the difference between accredited and non-accredited calibration?+
Accredited calibration (ISO/IEC 17025, via SAC-SINGLAS in Singapore) has had its methods, traceability and measurement uncertainty independently assessed by a national body. Non-accredited calibration produces a certificate but with no third-party assurance of competence, traceability or uncertainty.
Will an auditor accept a non-accredited calibration certificate?+
It depends on how critical the measurement is. For non-critical, indicative readings it may be acceptable. For measurements affecting product quality, safety, trade or a regulated process, auditors generally expect an accredited certificate with traceability and stated uncertainty.
What does an auditor look for on a calibration certificate?+
An accreditation mark and number, confirmation the discipline is within the lab's accredited scope, traceability to national standards, a stated measurement uncertainty, as-found/as-left data, clear instrument identification, and the calibration and due dates.
How do I check a calibration is within a lab's accredited scope?+
Ask for the lab's accreditation number and its scope of accreditation, then confirm your instrument's parameter and range fall within that scope. A reputable lab will tell you honestly whether a discipline is accredited or not.