3D printing / Filament
Filament Length and Weight Converter: Metres to Grams and Back
Convert 3D printing filament between length and weight from its diameter and the density of the plastic: see how many grams a length weighs, how many metres are on a spool, and how much is left on a partly used one.
Filament Length and Weight Converter: Metres to Grams and Back: 1.75 mm filament has a cross-section of 2.405 mm², so one metre is 2.405 cm³; at 1.24 g/cm³ for PLA that weighs 2.98 g, and a 1 kg spool holds about 335 m. The same metre of 2.85 mm PLA weighs 7.91 g. Runs 100% locally in your browser with zero server file uploads.
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Weight is the volume of the filament, its cross-section times its length, times the density of the plastic. The densities are typical values; check the spool's data sheet, since colour and additives change them by a few per cent. The weight is the filament alone, without the spool.
The formula
Weight in grams = π × (diameter ÷ 2)² × length × density ÷ 1,000, with the diameter and length in millimetres and the density in g/cm³.
Costing a print
Turn the grams into money with the 3D print cost calculator.
How to use it
- Choose the material and diameter.
- Enter a length in metres or a weight in grams.
- Read the converted weight or length.
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Frequently asked questions
How many metres are on a 1 kg spool?
About 335 m of 1.75 mm PLA, 327 m of PETG, and 400 m of ABS, which is lighter; 2.85 mm filament gives about 126 m of PLA.
How do I find out how much is left on a spool?
Weigh it and subtract the empty spool, often printed on the label or around 150 to 250 g, then convert the grams to metres.
Why do the densities differ from my spool?
Brands, colours, and fillers change density by a few per cent; use the figure from the data sheet if you need precision.
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