Convert Filament Length to Weight and Back
A free filament length and weight converter that handles 22 common 3D-printing materials. Switch a drop-down and the density auto-fills — PLA at 1.24 g/cm³, PETG at 1.27, ABS at 1.04, TPU, Nylon, carbon-fibre blends and more. Type a weight and read the metres, or type metres and read the grams.
How to convert filament length to weight
Choose from PLA, PETG, ABS, TPU, Nylon, carbon-filled and 17 more presets — density auto-fills.
Click 1.75 mm or 2.85 mm, or enter a custom value for specialty spools.
Fill the known side — the converter calculates the other instantly.
If your datasheet lists a different value, type it into the density field to override the preset.
Work out how many metres are left on a spool or how much a print will weigh — without unboxing a scale.
Filament
Amount
Net weight only — subtract the empty spool (usually 190–250 g) when weighing on a scale.
Quick spool presets
Features
Frequently asked questions
Does a 1 kg spool really hold 1 kg of filament?
The 1 kg rating means net filament weight — the empty spool typically adds another 190–250 g. Weigh a full spool, subtract the empty-spool weight, and use the remainder as your input.
How much 1.75 mm PLA is in a 1 kg spool?
About 330 metres of 1.75 mm PLA per kilogram at 1.24 g/cm³. Silk PLA is slightly shorter (~325 m) because of its higher density, PLA+ is close to standard PLA.
What density should I use for carbon-fibre PLA?
Use about 1.30 g/cm³ for standard carbon-filled PLA — slightly denser than pure PLA. Brand variations exist: always check the manufacturer spec sheet for accuracy.
Is the calculation affected by infill?
No — this tool converts between the length and weight of the filament itself, not a printed part. Slicer infill settings change how much filament a print consumes; the conversion factor from length to weight stays the same.
Can I use this for 2.85 mm Ultimaker spools?
Yes. Click the 2.85 mm diameter preset and the math scales correctly — a kilogram of 2.85 mm PLA is about 130 metres.
We can — and it's free! Just send us a quick message with your idea. If you'd like to discuss it in detail, leave your email and we'll get back to you. You can stay anonymous.
