Filamento: peso → comprimento

From filament weight to length

Spools are priced by weight, yet your slicer talks in meters. To bridge the two, use length = mass / (π·(d/2)²·ρ), with d being the filament diameter and ρ the density of the material. Take 1.75 mm filament. PLA (ρ ≈ 1.24 g/cm³) works out to roughly 330 m on a 1 kg spool, ABS (ρ ≈ 1.04) closer to 393 m, and PETG (ρ ≈ 1.27) about 323 m. TPU sits around 300 m but wanders depending on the blend. Switch to 2.85 mm and you get about 2.6× fewer meters for the same kilo. So a 250 g print in 1.75 mm PLA eats up something like 82 m.

Applications

Check whether a job is even feasible before you slice it. See if the meters left on a spool will cover the next print. Plan a multi-part project around a single spool. You can also compare cost across materials, since PLA is cheaper per meter while PETG or ABS sometimes need fewer meters for the same part. If you run an AMS or MMU setup, it helps to track what each color is actually using.

FAQ

Why does my slicer show a different length? It tacks on purge, the prime line, and the skirt. That overhead usually runs 1 to 3 m per print.

Does spool weight include the cardboard? What you care about is the net weight, the filament by itself. An empty cardboard spool runs 150–250 g, and a plastic one 200–300 g.

How to measure remaining filament? Put the spool on a scale, subtract the weight of the empty spool, and feed the grams into this calculator to get meters.