3D Print Filament Calculator — Weight, Length, and Cost
Filament → length / cost
Calculate filament length, cost per meter, and estimated remaining material from spool weight, diameter, density, and price.
Use this when
- Audience
- 3D printing users, print-farm operators, and small sellers checking whether a spool has enough usable filament for a job.
- Task
- Convert filament weight, diameter, density, and spool price into estimated length, cost per meter, and remaining material.
- Successful outcome
- Decide whether the remaining spool can cover the print, then use slicer output or the cost calculator for the next estimate.
- Boundary
- This is a planning calculator, not a measurement tool; real filament diameter, density, and spool tare weight vary by brand.
Best for
- Estimating how many meters of filament remain on a partial spool
- Comparing PLA, PETG, ABS, TPU, or custom material density assumptions
- Planning whether one spool is enough before starting a long print
- Converting filament weight into length for inventory and quoting workflows
Before you start
- Weigh filament without the empty spool, or subtract the known empty spool weight
- Use the actual filament diameter and density from the manufacturer when available
- Treat results as planning estimates because real diameter and density vary
- Use the print cost calculator when you also need material price and electricity cost
Next steps
Known Limitations
- Estimates assume round filament with consistent diameter
- Material density varies by brand and additives; adjust the density field for best results
- Results are planning estimates, not metrology-grade measurements
Frequently Asked Questions
How does the calculator convert filament weight to length?
It uses the formula: length = weight / (π × (diameter/2)² × density). Enter spool weight in grams, filament diameter (1.75 mm or 2.85 mm), and material density (g/cm³) to get length in meters.
What density should I use for PLA, PETG, and ABS?
Typical values: PLA ≈ 1.24 g/cm³, PETG ≈ 1.27 g/cm³, ABS ≈ 1.05 g/cm³, TPU ≈ 1.20 g/cm³. These vary by brand and color additives — check your spool label or manufacturer data sheet for the most accurate value.
Can I calculate how much filament is left on a partial spool?
Yes. Weigh the partial spool, subtract the known empty spool weight (usually printed on the spool hub), and enter the net filament weight into the calculator.
Does this calculator work for both 1.75 mm and 2.85 mm filament?
Yes. Enter the correct diameter in the diameter field and the calculation adjusts automatically.
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How it works
Your files are processed entirely inside your browser using Three.js. Your files never leave your browser — there is no server upload, no cloud storage, and no third-party processing. The converted file is generated as a local Blob and downloaded directly to your device. Once the conversion is complete, all data is released from memory.