Spool Remaining Calculator
Don't risk a print failure. Weigh your spool to know exactly what's left.
How This Tool Works
Stop playing "Filament Roulette." This tool uses basic subtraction (Gross Weight - Empty Spool Weight) to tell you exactly how much plastic you have left, so you don't run out 90% of the way through a 2-day print.
- Formula:
Current Weight - Empty Spool Weight = Filament Left - The Logic: You can't see the inner coils of a spool, but a scale never lies. By subtracting the weight of the holder (the spool), you get the net weight of the material.
- Assumptions: We assume standard densities for the length calculation (PLA is denser than ABS, etc.).
How to Use
- Weigh your spool: Put the currently used spool on a kitchen scale.
- Enter Empty Weight: If you don't know, use 250g for plastic or 100g for cardboard as a safe guess.
- Calculate: See if you have enough for that helmet file.
Example Calculation
You weigh a partially used spool of PLA: 1250g.
You know it's on a standard plastic spool: ~250g.
You need 800g for a print.
• Filament Remaining: 1000g
• Result: Safe to Print (You have ~200g buffer).
Why This Tool Is Accurate
Visual volume (looking at the remaining winds) is deceptive because the inner diameter of spools varies. Weight is absolute. If you have 500g of plastic and your slicer says 400g, you will succeed.
Limitations & Disclaimer
The weak link is the Empty Spool Weight.
• Manufacturers change spool designs constantly.
• If you guess the empty weight too low (e.g., guessing 200g when it's 250g), you might
think you have more filament than you actually do.
• Always leave a buffer (10-20g).
FAQs
It varies by manufacturer. Clear plastic spools are usually ~230g-250g. Black plastic spools are ~200g-220g. Cardboard spools are much lighter, around 90g-140g.
It's an approximation based on standard density (1.24g/cm³ for PLA). Weight is the only true measure, but the length estimate is good enough for checking if you have enough for a specific slice.
If you have a run-out sensor, the printer estimates pause and lets you swap. If not, the printer continues 'air printing' and the print fails. Use this tool to be safe!