Spool
Weigh the whole spool with filament still on it.
Default 200g is a typical estimate — check your spool for an exact figure.
Printed on the spool label — usually 1000g.
Advanced optionsDiameter and density — only used for the length estimate
Remaining
50%
- Remaining weight
- 500 g
- Remaining length
- 167.64 m
How it's calculated
A kitchen scale weighs the spool and the filament together, so the empty spool's own weight has to be subtracted out first:
Remaining weight
Weighed spool − Empty spool weight
Remaining %
Remaining weight ÷ Full spool net weight × 100
Remaining length
Remaining weight converted using material density & diameter
Assumptions
- Industry approximationEmpty spool weight defaults to 200g, a typical estimate for common cardboard/plastic 1kg spools. Actual weight varies by brand and material — override it for an exact result.
- Industry approximationMaterial density is a typical published value for that plastic; override it in advanced options if you know your filament's exact figure.
- Your inputWeighed spool weight, empty spool weight, and full spool net weight — you enter these directly.
Worked example
A spool of PLA that started at 1000g now weighs 700g on the scale. The empty spool itself weighs 200g.
Remaining weight = 700 − 200 = 500g. Remaining % = 500 ÷ 1000 × 100 = 50% — about half a spool left.
Frequently asked questions
What scale do I need?
Any kitchen or postal scale that reads in grams and can handle at least 1.5 kg is enough for most consumer spools. Place the whole spool on the scale — you don't need to remove the filament from the spool.
Why do I need to enter the empty spool weight?
The scale reads the combined weight of the spool and the remaining filament, so the empty spool's own weight has to be subtracted to get the actual filament weight. Empty spool weight varies by brand and material — cardboard spools are typically lighter than plastic ones. A default of 200g is used as a starting estimate, but check your spool or manufacturer's listing for the exact figure if you want a precise result.
How is the remaining percentage calculated?
It's the remaining filament weight divided by the spool's original net filament weight (usually 1000g or 1 lb / 454g, printed on the label), shown as a percentage.
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