Have you ever run out of filament mid print? This calculator will estimate the length of the remaining filament, based on 3 measurements of your spool.
Access the calculator:
https://jscalc.io/calc/1Cj6c1zxnr4q8Tzw
Works for **1.75mm** and **3mm** filaments. All measurements are in **mm**. The resulting length is in **m**.
**D** - Outer diameter of the remaining filament
**d** - Diameter of the inner coil
**W** - Inner width of spool
How it works: Calculates the volume of the filament on the spool and then divides by the area of the cross section of the filament. I have accounted for imperfect alignment of filament on the spool with a conservative factor of 0.8.