KNOW YOUR SPOOL · PRINTVELD TOOLS
Filament length & weight
calculator.
Turn grams into metres, or metres into grams. Set your filament diameter and material density for a useful spool estimate.
Your inputs
EDITABLE EXAMPLESTHE NEXT LAYER
Your estimate
Adjust the examples, then select Calculate.
BEHIND THE NUMBERS
From spool weight to filament length
The estimate treats filament as a cylinder with a constant diameter. Its cross-sectional area is π × diameter² ÷ 4. With diameter in millimetres, length in metres and density in g/cm³, grams = length × area × density.
Density changes with the material, brand and additives. The starting density of 1.24 g/cm³ is an example from PolyLite PLA, not a value for every PLA or other filament. Diameter variation and moisture also affect the estimate.
Further reading: PolyLite PLA product data sheet ↗
Grams = metres × (π × diameter² ÷ 4) × density
Metres = grams ÷ ((π × diameter² ÷ 4) × density)
Useful to know
Can I use this for PETG, ABS or flexible filament?
Yes. Enter the density for your specific filament from its manufacturer’s technical data sheet. The default PLA example should be changed for other materials.
How do I estimate a partly used spool?
Weigh it and subtract the empty spool’s weight. Enter the remaining net filament weight to estimate its length.
Can this tell me whether I have enough for a print?
Compare the estimate with your slicer’s total requirement and leave a reserve for purge and variation. The tool cannot measure the spool or guarantee an exact remaining length.
NUMBERS START A CONVERSATION.
What worked on your printer?
Bring your settings, results and questions to the PrintVeld forum.