How accurate do our meters and scales have to be for CBAM, and what if one fails?

The Commission's guidance says the biggest sources, above 500,000 tonnes CO2 a year, should reach 1.5% uncertainty or better, while sources below 10,000 tonnes are acceptable at under 7.5%, if the cost is reasonable. A replacement instrument must be at least as accurate as the old one.

The guide values

The aim is accuracy in proportion to size, with the lowest uncertainty on the biggest parts of your emissions.

• Source streams above 500,000 tonnes CO2 a year: uncertainty over the full reporting period of 1.5% or better.
• Source streams below 10,000 tonnes CO2 a year: uncertainty below 7.5% is considered acceptable.
• These apply if they do not lead to unreasonable costs.

Replacing an instrument

If a meter fails, or calibration shows it no longer meets the uncertainty you claimed, replace it with one that meets the same or a better level. The guidance says to keep improving the monitoring method but never to fall below the existing standard.

What to do now

1. Rank your source streams by tonnes of CO2 a year.
2. Check the stated uncertainty of the instrument on each large stream against the guide value.
3. Keep calibration certificates with the monitoring plan.
4. If you must swap a meter mid-year, tell your verifier and keep the data from both.

What Senseible does here

Senseible reads your fuel, power and steam bills into verified emission records, so the monthly figures a monitoring plan needs are ready to hand to your verifier. Verified here means rule checks passed against the evidence. It is not third-party assurance, and a CBAM verifier still signs the report.

• Does meter uncertainty count in CBAM materiality?
• Meter failure and data gaps
• CBAM Suite

Sources: European Commission, CBAM Guidance No. 3, calculation of embedded emissions

Last reviewed 2026-11-04.