How do I know how much filament is left on a spool?

The most accurate way is to weigh the spool on a kitchen scale and subtract the weight of the empty reel. What remains is the filament. From the weight, you can calculate the remaining meters using the material density and the filament diameter.

Can I estimate it without a scale?

Yes. By measuring the outer diameter of the wound filament, the core diameter and the spool width with a ruler, you can estimate the remaining length and weight. It is less accurate than weighing, but it helps when there is no scale.

Tools › Remaining spool weight

Remaining spool weight

Find out how many grams and meters of filament are still left on your spool — by weighing it on a scale (most accurate) or measuring with a ruler. Everything happens in your browser; nothing is sent to any server.

How do you want to calculate?

Material

Filament diameter

Current total weight of the spool (g)

Place the whole spool (with the reel) on a kitchen scale.

Brand (empty reel)

Empty reel weight (g)

The per-brand weights are approximate; if the packaging states the reel weight, use that value.

Full capacity (g)

To calculate the % remaining.

Price per kilo (R$) — optional

To see how much it is still worth.

The part I want to print uses (g) — optional

To see if you can print it with what is left.

Result

—

of a full spool

Filament remaining

—

Length remaining

—

In LayerDesk this is automatic

Each production run already deducts the grams from the spool and shows the full/empty gauge — no scale and no spreadsheet. It even warns you when a color is running low.

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How the calculation works

When weighing, the remaining filament is the total spool weight minus the empty reel weight. To turn grams into meters we use the material density and the cross-sectional area of the filament: the denser the material and the thicker the filament, the fewer meters per gram. When measuring, we estimate the length from the volume of the ring of wound filament (outer diameter, core and width) and convert it into weight using density.

Densities and reel weights are reference values and may vary by brand and batch. For maximum accuracy, weigh the spool and enter the real empty reel weight.

Remaining spool weight

How the calculation works

Frequently asked questions