Tape Accuracy

When it comes to precision work, tape accuracy is a key factor and is determined by standards set by the European Committee, which divide the category in three classes according to their level of accuracy.

• EC Class I: they are the most accurate tape measures on the market. They tend to be slightly more expensive than the average DIY tool, but are perfect for professional work where precision is not something to compromise on. The maximum error expected in class I tapes is of 1.1 mm in 10 meters – 0,001 % of margin.
   
• EC Class II: slightly less accurate than class one, but still significantly more precise than the average commercial tape and suitable for all uses and pockets. The maximum error expected over 10 meters total length is 2.30 millimetres – slightly more than the 0.002%.
   
• EC Class III: the least accurate on the scale, therefore they might be preferred where a difference of a few millimetres does not make a difference on the overall result and does not impact the stability or the safety of the project. The maximum margin of error on a 10 metres long measure is 4.60 millimetres – 0.004 % difference.

Deviation ± mm over total length

(Source: https://www.sola.at/global-en/competences/short-tape)