Filament Weight and Length Calculator

It treats filament as a round rod. The cross-section area is pi times the radius squared, the volume is that area times the length, and the weight is the volume times the density you selected. Grams back to meters runs the same relation in reverse.

The presets use PLA 1.24, ABS 1.04, PETG 1.27, TPU 1.21 and Nylon 1.14 g/cm3. These are typical averages, so if your spool label lists a density or a length-per-kilogram figure, override the field to match it for a closer result.

Yes. Switching to 2.85 mm uses a larger cross-section, so the same length weighs about 2.65 times more than 1.75 mm filament of the same material. Both are common, and choosing the wrong one is the usual cause of a surprising result.

Spools advertise net filament weight, but real filament varies. Diameter tolerance, absorbed moisture and colorant pigments all shift the effective density slightly, and manufacturers round their labels. Treat the output as a close estimate rather than an exact scale reading.

Yes. Choose 'Weight to length' and enter a weight in grams. The tool divides the weight by density to recover volume, then solves the cylinder relation for length, showing meters and volume alongside.

Density accepts 0.5 to 3 g/cm3, length runs from 0 to 2000 m and weight from 0 to 5000 g. Values must be positive; a zero or negative entry produces an error instead of a result.

No. It converts a raw length or weight of filament only. To estimate the filament a specific model needs, read the length or weight from your slicer after setting infill and walls, then paste that number here.

No. The math runs entirely in your browser, so the numbers you type never leave your device. You can use it offline once the page has loaded.

Yes. The tool exposes a JSON API that takes diameterMm, density and one of lengthM or weightG, and returns lengthM, weightG and volumeCm3, so you can wire it into batch spool-tracking scripts.