3DPrintCalcs
Spool Life Calculator — How Long Will a Spool Last?
Estimate how many prints and how many weeks you can get from one spool of filament.
How We Calculate This
Formula
- Usable weight = Spool weight x (1 - Waste %)
- Total prints = Usable weight / Average print weight
- Duration = Total prints / Prints per week
Frequently Asked Questions
Typically 5-15%. This covers failed prints, purge/prime lines, calibration prints and skirt/brim waste. 10% is a good default for most users.
Check your slicer estimates for your last 10-20 prints and calculate the average. Most people print a mix of small and large objects.
No, enter only the net filament weight. A standard spool is labelled as 1kg (1000g) of filament. The plastic spool itself weighs 150-250g extra but is not included in the labelled weight.
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Calculate filament ratios for multi-colour or gradient prints.
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Compare cost per gram and value across different filament brands and spool sizes.
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Last updated: February 2026
All calculations are estimates. Always verify settings with test prints before committing to final prints.