Filament Length & Weight Calculator
Convert between 3D printer filament length and weight for PLA, ABS, PETG, and other materials, free in your browser.
Enter Values
Minimum 0
How to use this calculator
- Enter either the filament length (m) or the weight (g) — whichever you know.
- Optionally set the diameter (default 1.75 mm) and the material density.
- Read the matching value, plus grams per metre and how long a 1 kg spool is.
How it works
The Filament Length & Weight Calculator converts between how much filament weighs and how long it is, from the filament's diameter and material density.
Grams per metre = the filament's cross-section area (π·d²/4 in mm²) × the density (g/cm³), because one metre of a mm²-section equals that many cm³. Length and weight then follow from each other. A 1 kg spool of 1.75 mm PLA is about 335 m.
Worked example
1 kg of 1.75 mm PLA. At 1.24 g/cm³, that's about 2.98 g/m, so a 1 kg spool holds roughly 335 m of filament.
Frequently asked questions
What density should I use?
Common values are PLA 1.24, PETG 1.27, ABS 1.04, TPU 1.21 and Nylon 1.14 g/cm³. Check your filament's spec sheet for the exact figure.
Does colour or brand change the length?
Slightly — fillers and additives shift the density a little, and diameter tolerance varies by brand. Use the manufacturer's density for the closest result.
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Cite this tool
Zerdly. (2026). Filament Length & Weight Calculator. Retrieved from https://www.zerdly.com/tools/filament-length-weight-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.