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 sti