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Weights and Measures Office

Users of weighing and measuring instruments for trade

Ensure your trade instruments are pattern registered and verified before use. Using unregistered or unverified instruments is an offence under the Weights and Measures Act.

Last updated 8 June 2026

For users of weighing and measuring instruments for trade use

Ensure that the weighing/measuring instrument has been pattern registered with the Weights and Measures Office

Businesses using weighing or measuring instruments for trade (i.e., where transactions are based on the quantity measured by the instrument) must use instruments pattern registered with the Weights and Measures Office (WMO). The instrument will then need to be verified by an Authorized Verifier (AV) and affixed with the ACCURACY Label before it can be used for trade purpose.

You can find a list of WMO pattern registered weighing and measuring instruments in the Register of Weighing and Measuring Instruments Granted Pattern Approval.

Submit the instrument to an Authorized Verifier to verify that it is fit for trade use

Under the Weights and Measures Act, it is an offence to use unregistered i.e., not pattern registered, and/or unverified instruments for trade in Singapore.

Businesses can contact one of the Authorized Verifiers (AVs) which are appointed by the WMO to carry out verification of these instruments. Their contact details can be found on our Register of Authorized Verifiers.

Instrument verification records are immediately approved when submitted by the AV through the WMO's application website (CPSA+). Members of public and businesses will be able to view the details of the instruments using the Register of Instruments.

Please refer to Appendix E of the Weights and Measures Information Booklet below for the process to get your instrument verified.

QR code label and registration of weighing and measuring instruments in CPSA+

The CPSA+ is an application website where AVs can submit verification records, as well as where the public registry of pattern registered instruments, list of weighing and measuring instrument used for trade, list of designated AVs, etc. are hosted.

Instrument owners can also login to CPSA+ to view information related to the weighing and measuring instruments they use for trade, e.g. the verification status of the instrument, it’s operating location, etc. The instrument would first need to be registered in CPSA+ before this information will be viewable.

Effective 30 November 2021, weighing and measuring instruments used for trade will be affixed with a QR code label bearing a unique 7-digit identification number for purpose of instrument registration in the CPSA+ system. The QR code label is to be affixed on the instrument by an AV prior to conducting the initial verification. The QR code will be affixed next to the ACCURACY Label or, in a position on the instrument easily seen by consumers.

Red badge reading Accuracy Label, verified April 2021, with a QR code labeled WMO and number 2100001.

The first 2 digits of the identification number represent the year the instrument was registered in CPSA+. For example, if the instrument was registered by the AV in 2021, the unique identification number for the instrument would thus start with ‘21’ followed by its serialised number e.g., 21XXXXX.

Unlike the ACCURACY Label which is valid for 12 months, and has to be replaced prior to its expiry, the QR code label is meant to be permanent, and should only be changed by an AV if it is found damaged or missing from the registered instrument.

Notifications from CPSA+

For registered businesses with UEN, the contact information provided to the AVs for purpose of instrument registration will receive the following notifications from CPSA+:

  • List of instruments successfully registered by the AV in CPSA+

  • List of instruments verified by the AV after its record has been successfully submitted in CPSA+

  • A reminder that there are instruments due for re-verification in 2 months’ time

  • A reminder that there are instruments with lapsed ACCURACY Labels and to contact an AV for re-verification before they are used for trade

  • Replacement of Instrument ID for any of your registered instruments

Registered businesses with UEN may also login CPSA+ to update your contact information or location of your instrument if there are any changes.

For instrument owners with no UEN, notifications on the instruments will be sent via SMS based on the contact information provided to the AVs for instrument registration.

You may find out more about the QR code label and registration of instruments in CPSA+ in Chapter 4.2 of the Weights and Measures Information Booklet.

For more information on how to login to CPSA+ and access information about your registered instruments, click here and refer to the CPSA+ guidebook for weighing and measuring instrument owners.

Metric system of units

Traders should also ensure that you use the metric system of units when transacting or advertising goods. For example, Kilogram for goods measured by weight, and Litre for goods measured by volume.

More information on Weights and Measures can be found below.