Free tool — no sign-up. Reader-supported: if it helped, shopping through our buying guides below keeps it free. No extra cost to you. See guides ↓ As an Amazon Associate we earn from qualifying purchases.
Slicers report filament in grams or meters, spools are sold by the kilogram, and remaining filament is easiest to weigh. This calculator converts between length and weight for any common material and diameter and works out what a print costs you in material.
The formula
Weight (g) = π × (diameter ÷ 2)² × length × density. With diameter in millimeters and length in meters: 1 m of 1.75 mm filament has a volume of 2.405 cm³, so 1 m of PLA (1.24 g/cm³) weighs about 2.98 g.
Filament per 1 kg spool
| Material | Density | 1.75 mm: length per kg | 2.85 mm: length per kg |
|---|---|---|---|
| PLA | 1.24 g/cm³ | ~335 m | ~126 m |
| PETG | 1.27 g/cm³ | ~327 m | ~123 m |
| ABS | 1.04 g/cm³ | ~400 m | ~151 m |
| ASA | 1.07 g/cm³ | ~389 m | ~147 m |
| TPU | 1.21 g/cm³ | ~344 m | ~130 m |
| Nylon (PA) | 1.14 g/cm³ | ~365 m | ~138 m |
| Polycarbonate | 1.20 g/cm³ | ~347 m | ~131 m |
Densities are typical values; blends and filled filaments (carbon fiber, wood, glow) vary. Check your manufacturer’s data sheet for exact figures.
Checking how much is left on a spool
Weigh the spool and subtract the empty spool weight — typically 150–250 g for plastic spools and less for cardboard. Enter the result as the print weight to see the remaining length.
FAQ
Why does the actual print use more filament than the slicer said?
Purge lines, skirts, failed first layers and supports you break off all add up. Budget 5–10% extra.
Does filament diameter tolerance matter?
Yes: a ±0.03 mm variation on 1.75 mm filament changes volume by about ±3.5%. Quality brands hold tighter tolerances, which gives more consistent extrusion.
More free tools
- Barbell Plate Calculator — Which plates go on each side for any target weight, in lb or kg.
- Garage Gym Flooring Calculator — How many stall mats, tiles or feet of rubber roll cover your gym floor.
- Shelf Sag Calculator — How Much Weight Can a Shelf Hold? — How much a shelf sags — and the most it can hold before it shows.
- Workbench Height Calculator — The right bench height for your height and the work you do.
- 3D Printer Filament Types & Temperature Chart — Which filament for your part, with print temps and drying settings.
- Air Compressor Size Checker — What CFM and tank size your air tools really need.
- Bolt Torque Chart (SAE & Metric) — Typical torque specs by bolt size, pitch and grade.
- Cordless Tool Platform Comparison Quiz — Answer 5 questions, get a Milwaukee / DeWalt / Makita / Ryobi steer.
- All tools