Remaining Filament Measuring Tool

I got tired of not knowing if I had enough filament left on my spool to print my next project. So, I made this tool to measure the remaining filament on the spool. You may have to modify it for different spool sizes. I am not sure if they differ. The tool is graduated in layers of filament. Use that number with the attached spreadsheet to determine how much filament you have left.

10/16/2020 I realized that the markings were off by one. The picture of this item is not updated and is still wrong, but all the files have been updated. The picture shows the first mark at the zero position. I have fixed that in the files.