Filament Length Calculator
Convert filament weight to length in meters and feet for any material.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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This calculator converts filament weight to length using each material's known density. Filament is sold by weight (typically 1kg spools) but slicers often report usage in meters or grams. Here is how to use the tool:
- Enter weight in grams. For a full spool, enter 1000. For remaining filament, weigh your spool on a kitchen scale and subtract the spool weight (usually 200-250 grams, check the spool or manufacturer's site).
- Select your filament diameter. Most consumer printers use 1.75mm. Ultimaker, some Lulzbot, and a few other printers use 2.85mm (often labeled 3mm).
- Select the material. Each material has a different density, which directly affects how many meters of filament a given weight produces. ABS is less dense than PLA, so 1kg of ABS filament is longer than 1kg of PLA.
- Read the result. The calculator shows total length in meters and feet. Use this to check how much filament remains on a spool or to verify a slicer's estimate.
About the Filament Length Calculator
The formula is: length (cm) = weight (g) / (PI * radius² (cm²) * density (g/cm³)). The radius is converted from mm to cm (divide by 20 for radius in cm). The result is converted to meters by dividing by 100. A 1kg spool of 1.75mm PLA (density 1.24 g/cm³) yields approximately 335 meters (1,099 feet). The same weight in ABS (density 1.04 g/cm³) gives about 399 meters because ABS is less dense.
Filament densities used: PLA 1.24, ABS 1.04, PETG 1.27, TPU 1.21, Nylon 1.14, ASA 1.07 (all in g/cm³). These are typical values. Specialty blends (glow in the dark, silk, wood-fill, carbon fiber) may vary slightly. All calculations run in your browser. No data is stored or transmitted.
Frequently Asked Questions
How many meters of filament are on a 1kg spool?
For 1.75mm PLA (density 1.24 g/cm³), a 1kg spool contains approximately 335 meters (1,099 feet). For ABS, it is about 399 meters because ABS is less dense. For PETG it is around 328 meters. The exact length varies by material density and can be calculated precisely using this tool.
How do I know how much filament is left on my spool?
Weigh the spool on a kitchen scale. Then subtract the empty spool weight, which is usually 200-250 grams (check the manufacturer's website or look for the weight printed on the spool hub). Enter the remaining filament weight in grams into this calculator to see how many meters are left.
What is the difference between 1.75mm and 2.85mm filament?
1.75mm is the current dominant standard used by most consumer printers including Prusa, Bambu Lab, Creality, and Anycubic. 2.85mm (often marketed as 3mm) was an earlier standard still used by Ultimaker printers and some professional machines. The two diameters are not interchangeable. Check your printer's manual to confirm which diameter it requires. This calculator supports both.
Why does material type affect filament length?
Different plastics have different densities. ABS (1.04 g/cm³) is less dense than PLA (1.24 g/cm³), so the same weight of ABS occupies more volume, which means a longer filament strand. PETG (1.27 g/cm³) is slightly denser than PLA and gives slightly less length per gram. The difference between materials on a 1kg spool can be 50-100 meters, which matters when estimating whether you have enough filament for a print.