Filament Remaining Calculator
Calculate filament remaining for calibrating and tracking a 3D printer.
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What this tool does
Calculate filament remaining for calibrating and tracking a 3D printer. Brand tare weights are the brands' published approximate empty-spool weights and vary a few grams between spool batches — weigh one of your own empty spools and use the override for the most accurate result. Length uses the nominal diameter and the PLA density default (1.24 g/cm³); PETG is 1.27 and ABS is 1.04 g/cm³.
How to use the Filament Remaining Calculator
- Enter or select spool + filament weight on scale (grams).
- Enter or select empty spool (tare) by brand.
- Enter or select tare override (grams, 0 = use brand table).
- Enter or select filament diameter (mm).
- Enter or select material density (g/cm³).
- Enter or select full spool filament weight (grams).
- Read the calculated result; change any measurement to compare alternatives.
Formula
remaining filament = gross weight − spool tare; grams per metre = π × (diameter mm ÷ 20)² × 100 × density; remaining length = remaining grams ÷ grams per metre; percent full = remaining ÷ nominal spool weight × 100
- gross
- Spool + filament weight on scale (grams)
- brand
- Empty spool (tare) by brand
- tareOverride
- Tare override (grams, 0 = use brand table)
- diameter
- Filament diameter (mm)
- density
- Material density (g/cm³)
- nominal
- Full spool filament weight (grams)
Brand tare weights are the brands' published approximate empty-spool weights and vary a few grams between spool batches — weigh one of your own empty spools and use the override for the most accurate result. Length uses the nominal diameter and the PLA density default (1.24 g/cm³); PETG is 1.27 and ABS is 1.04 g/cm³.
Worked example
For filament remaining calculator, the following measurements illustrate the exact method: Spool + filament weight on scale (grams): 850; Empty spool (tare) by brand: prusament; Tare override (grams, 0 = use brand table): 0; Filament diameter (mm): 1.75; Material density (g/cm³): 1.24; Full spool filament weight (grams): 1000.
Inputs
- Spool + filament weight on scale (grams)850
- Empty spool (tare) by brandPrusament spool — approx. 200 g
- Tare override (grams, 0 = use brand table)0
- Filament diameter (mm)1.75
- Material density (g/cm³)1.24
- Full spool filament weight (grams)1000
Result
- Filament remaining (grams)650
- Filament remaining (metres)217.93
- Spool full (%)65
- Tare used (grams)200
- Filament already used (grams)350
Results explained
- Filament remaining (grams)
- Filament remaining (grams) from the formula above. Brand tare weights are the brands' published approximate empty-spool weights and vary a few grams between spool batches — weigh one of your own empty spools and use the override for the most accurate result. Length uses the nominal diameter and the PLA density default (1.24 g/cm³); PETG is 1.27 and ABS is 1.04 g/cm³.
- Filament remaining (metres)
- Filament remaining (metres) from the formula above. Brand tare weights are the brands' published approximate empty-spool weights and vary a few grams between spool batches — weigh one of your own empty spools and use the override for the most accurate result. Length uses the nominal diameter and the PLA density default (1.24 g/cm³); PETG is 1.27 and ABS is 1.04 g/cm³.
- Spool full (%)
- Spool full (%) from the formula above. Brand tare weights are the brands' published approximate empty-spool weights and vary a few grams between spool batches — weigh one of your own empty spools and use the override for the most accurate result. Length uses the nominal diameter and the PLA density default (1.24 g/cm³); PETG is 1.27 and ABS is 1.04 g/cm³.
- Tare used (grams)
- Tare used (grams) from the formula above. Brand tare weights are the brands' published approximate empty-spool weights and vary a few grams between spool batches — weigh one of your own empty spools and use the override for the most accurate result. Length uses the nominal diameter and the PLA density default (1.24 g/cm³); PETG is 1.27 and ABS is 1.04 g/cm³.
- Filament already used (grams)
- Filament already used (grams) from the formula above. Brand tare weights are the brands' published approximate empty-spool weights and vary a few grams between spool batches — weigh one of your own empty spools and use the override for the most accurate result. Length uses the nominal diameter and the PLA density default (1.24 g/cm³); PETG is 1.27 and ABS is 1.04 g/cm³.
Frequently asked questions
Weigh the whole spool, subtract the empty spool's tare weight, and the difference is filament. An 850 g gross spool on a Prusament spool (about 200 g tare) holds about 650 g of filament — roughly 218 m of 1.75 mm PLA.
They are the approximate empty-spool weights the brands publish or state in their support material (for example Prusament ≈200 g, Polymaker's cardboard spool ≈170 g), and every option is labelled 'approx.' because spool batches vary. Your own empty spool of the same brand, weighed once and entered as the override, beats any table.
Yes — enter any value in the tare override field and it replaces the brand-table value (0 means use the table). This also covers brands that are not listed and refill spools, where the 'spool' may be a reusable holder you can weigh directly.
Weight is exact; length depends on real diameter and density. Nominal 1.75 mm PLA at 1.24 g/cm³ runs about 2.98 g per metre, but filament that averages 1.72 mm or 1.78 mm shifts the length by roughly ±3–4%. For 'will this print finish?' decisions, grams compared against the slicer's grams estimate is the safer check.
Either the wrong brand/tare is selected (spools differ by 30–80 g), the spool is a smaller size than the table assumes, or the scale includes/excludes something extra. The calculator shows an error rather than a negative filament amount; weigh the empty spool and use the override.