Boneyard Tools

Filament Weight and Length Calculator

Enter a filament diameter and material density, then a length or a weight, to get the matching weight, length and volume. Useful for spool planning and gcode estimates.

How to calculate filament weight

  1. Pick your filament diameter (1.75 mm or 2.85 mm).
  2. Choose the material so the density is set, or enter a custom density.
  3. Enter either a length in meters or a weight in grams.
  4. Read the converted weight, length and volume.

Examples

330 m of 1.75 mm PLA

diameter 1.75 mm, density 1.24, length 330 m
about 984.24 g (793.74 cm3)

A full 1 kg PLA spool

diameter 1.75 mm, density 1.24, weight 1000 g
about 335.28 m of filament

Frequently asked questions

How is filament weight calculated from length?

The filament is treated as a cylinder. Cross-section area is pi times radius squared, volume is area times length, and weight is volume times density.

What density should I use for each material?

Common densities in g/cm3 are PLA 1.24, ABS 1.04, PETG 1.27, TPU 1.21 and Nylon 1.14. Check your spool label, since brands vary slightly.

Does it support 2.85 mm filament?

Yes. Pick 2.85 mm and the larger cross-section is used, so the same length weighs more than 1.75 mm filament.

Why does my estimate differ from the spool weight?

Spools list net filament weight, but diameter tolerance, moisture and colorant pigments shift real density a little, so treat the result as a close estimate.

Can I convert grams back to meters?

Yes. Enter a weight instead of a length and the tool divides weight by density to get volume, then solves the same relation for length.

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