How to use it
- Pick the material, or enter a custom density.
- Choose the filament diameter: 1.75 mm, 2.85 mm or other.
- Enter a length or a weight, or weigh your spool.
- Read the result and the meters-per-kilogram table.
The formula
Filament is a long cylinder, so its weight follows directly from its length:
weight = length × π × (diameter ÷ 2)² × density
For 1.75 mm filament the cross-section is π × 0.875² ≈ 2.405 mm². One meter is therefore 2,405 mm³, or 2.405 cm³. With PLA at 1.24 g/cm³, one meter weighs about 2.98 g, and a 1 kg spool holds about 335 m.
The calculator shows the result in grams and meters, with ounces and feet alongside for reference. Filament is sold and sliced in metric units, so grams and meters are what your slicer reports.
Meters per kilogram by material
Typical densities and the length of a 1 kg spool:
| Material | Density (g/cm³) | 1.75 mm: m per kg | 2.85 mm: m per kg |
|---|---|---|---|
| PLA | 1.24 | ~335 | ~126 |
| PETG | 1.27 | ~327 | ~123 |
| ABS | 1.04 | ~400 | ~151 |
| ASA | 1.07 | ~389 | ~147 |
| TPU | 1.21 | ~344 | ~130 |
| Nylon (PA) | 1.14 | ~365 | ~138 |
Densities vary by a few percent between brands because of fillers and pigments. Carbon-fiber and wood-filled blends are different again, so check the datasheet and type the density in if it is listed.
How much filament is left on my spool?
Weigh the spool on a kitchen scale and switch to How much is left on the spool?. Enter the gross weight and the weight of an empty spool, and the calculator returns the filament left in grams and meters.
Empty spools typically weigh 120–300 g depending on the brand and whether they are plastic or cardboard. The most accurate approach is to weigh an empty spool of the same brand once and remember the number.
If you enter how much the next print needs (from your slicer), the calculator tells you whether it is enough, whether it is cutting it close (less than 10% to spare), or how much you are short.
Why the numbers differ slightly from your slicer
- Diameter tolerance: a spool listed as ±0.02 mm can be 1.73–1.77 mm, which changes the weight per meter by about 2%. Cheaper filaments may be ±0.05 mm.
- Density setting: slicers use the density in your filament profile; if it is left at a default, the gram estimate can be off.
- Purge and priming: the slicer may or may not count the purge line, wipe tower or skirt.
For a full cost breakdown including electricity and machine time, use the 3D print cost calculator.
Quick conversions
- 1 m of 1.75 mm PLA ≈ 3 g, so 100 m ≈ 300 g.
- 1 kg of 1.75 mm PLA ≈ 335 m (about 1,100 ft).
- 1 kg of 2.85 mm PLA ≈ 126 m.
- 1 lb (454 g) of 1.75 mm PLA ≈ 152 m.
A handy habit: write the remaining weight on the spool with a marker or a sticky label each time you take it off the printer. Combined with the slicer's gram estimate, you will rarely start a long print that runs out halfway. Everything on this page is calculated in your browser.
Frequently asked questions
How many meters are in a 1 kg spool of PLA?
About 335 m for 1.75 mm PLA and about 126 m for 2.85 mm PLA, assuming a density of 1.24 g/cm³.
How much does 1 meter of filament weigh?
About 3 g for 1.75 mm PLA. Denser materials like PETG weigh a little more, lighter ones like ABS a little less.
How do I know how much filament is left?
Weigh the spool, subtract the empty spool weight and convert the rest to meters with the spool tab of this calculator.
What does an empty filament spool weigh?
Usually between 120 and 300 g. Weigh an empty spool of your brand for the best accuracy.
Does filament diameter matter much?
Yes. 2.85 mm filament has about 2.65 times the cross-section of 1.75 mm, so the same weight is much shorter.
Last updated: November 12, 2026