Very complete, so complete if you are looking for an light daily convertor for usual metric conversions.

When it comes to simplicity of the user interface and how thorough the unit conversion between metric and imperial units, this is the best extension I found so far, but Avast antivirus detected it as an unsafe extension and removed it. I do not know if it is false positive on the part of Avast but it certainly brings concern. I cannot, without hesitation, recommend it for that reason.