3D Printer Filament and Spool Planner
Convert round filament mass and length, subtract spool tare and estimate whole print jobs after reserve and allowance.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Treat the filament as a uniform round cylinder. Multiply its cross-sectional area by length and density, or reverse that equation. Remove empty-spool mass when weighing a spool, then reserve material and round whole print jobs down.
Area=π(d/2)²; mass=area×length×density; whole jobs=floor(max(0,net mass−reserve)/(job mass×(1+allowance)))
Worked example
At entered diameter 1.75 mm and density 1.24 g/cm³, 300 g corresponds to about 100.59 m. Reserving 20 g and allowing 5% extra on a 100 g job permits two whole jobs, leaving 90 g total.
Assumptions and input details
Density 1.24 is an editable numerical example, not a universal material or brand property. Use the actual filament data and diameter; hollow, foamed or nonround material is outside this cylinder model. Job mass should come from a slicer or measured job; this is not model-volume or infill prediction. If that mass already includes supports/purge/waste, avoid counting the same allowance twice. Spool tare is excluded from usable filament. Blank price stays unknown; energy, machine time and labor costs are separate.
References: Prusa: filament and nominal diameters
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Choose from 23 length definitions, including explicitly labelled regional measures. Area conversions square the length factor; geometric volumes cube it.
The 19 mass definitions distinguish avoirdupois and troy measures, metric and regional measures. Japanese kin is 600 g; mainland Chinese shijin is 500 g.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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