Since Measure is an add-on for Excel, I can only assume that you have not set the cell format to display any more decimal places. Right click on the cell and select Format Cells>Number and change the Decimal Places control.
If you aren't using Measure, then you need to post your question to an appropriate language or hardware board. And if you post to a hardware board, provide the language that you are using and how you think you are only getting 3 digits.
