Filament Weight Measurement Tool

Have you ever struggled to figure out how much filament is left on your spool?

If you've searched for filament measuring tools online, you've probably come across several 3D printed spool gauges with weight markings. But here's the thing—they're all based on a flawed assumption.

Most of these tools simply divide the visible height of the filament on the spool into equal segments, as if the filament is being used up in straight, consistent layers. That’s not how filament works.

Here’s the reality:

Filament is wound around a spool in coils, from the inside out when loading, and consumed from the outside in when printing. As filament wraps around the spool, each new layer sits on top of the previous one—adding to the spool’s diameter. This means:

• Each outer layer of filament requires more material to make a full loop than the layer beneath it.
• As a result, the amount of filament per millimeter of height changes—it’s not a linear relationship.
• The higher the filament is on the spool, the more filament is stored per layer.

Why does this matter?
If a measuring tool uses equal-height divisions for estimating weight, it gives misleading results. The outermost layer might represent much more filament than the innermost one, but a traditional gauge treats them as the same.

That’s why this tool was designed differently.

This 3D printed filament weight gauge uses non-linear height markings—accurately calculated to reflect the real amount of filament left based on the geometry of a typical spool and filament diameter which is 200mm outside diameter and 85mm spool shaft diameter. It’s a smarter, more accurate way to check how much you’ve got left before starting a big print.

Design by LA Adriano on MakerWorld (license: BY).