A high-quality moisture meter used on the right material can be accurate to within less than 0.1% of the material's moisture content by weight. However, a low-end moisture meter can be wildly inaccurate.

Can moisture meters be wrong?

If someone uses a moisture meter but doesn't get accurate assessments of moisture content (%MC), then they could make a mistake based on that bad information which costs time, money, and resources. Sometimes, people using moisture meters can make a mistake that causes inaccurate moisture measurements.

What is an acceptable reading on a moisture meter?

In general, any reading between 6 and 10% is considered normal here. Now if you are testing exterior wood that has direct contact with the surrounding humidity, you can tolerate values that are up to 20%. Things start to get worrying when the meter indicates higher values than 20%.