Filament Length Calculator — Metres per Spool
Calculate the total length of filament on a spool from its weight, diameter and material density.
Net filament weight (not including spool)
How We Calculate This
Formula
The calculator uses the relationship between mass, density, and volume:
- Volume = Weight / Density
- Cross-sectional area = pi x (diameter/2)^2
- Length = Volume / Cross-sectional area
The weight is divided by the material density to get total volume in cm3, then divided by the filament cross-sectional area to get length in centimetres, which is converted to metres.
Frequently Asked Questions
Related Calculators
Filament Weight Calculator
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Filament Cost Calculator
Work out the material cost of a print based on filament weight and spool price.
Spool Life Calculator
Estimate how many prints you can get from one spool of filament.
Filament Diameter Calculator
Calculate cross-sectional area and volume per metre for any filament diameter.
Filament Density Calculator
Look up or calculate filament density for common 3D printing materials.
Last updated: February 2026
All calculations are estimates. Always verify settings with test prints before committing to final prints.