Browser-only OrcaSlicer filament tool

Filament Length to Weight Calculator

A slicer reports filament use as a length, a scale reports it as a weight, and a spool is sold by weight. This calculator converts between the two in both directions from the filament diameter and density you enter, adds grams per metre, volume and cost, and estimates how much filament is left on a part-used spool. Every calculation runs in this page — nothing you type is uploaded, stored or sent to a server.

1 — Filament and spool price

Diameter and density decide how much a metre of filament weighs. Take both from the profile or the datasheet of the spool in front of you rather than from a generic table.

The presets are nominal profile values. Filled, foamed and heavily pigmented blends differ, so edit the density if the spool says something else.

Enter the price in your own currency; the page never labels it, and the cost outputs stay hidden while the field is empty or zero.

2 — Length or weight

Pick the direction you have a number for. The other side is derived from the diameter and density on the left.

Conversion direction

The length the slicer reported, in metres. 1 m = 1000 mm, so a preview that says 12,450 mm is 12.45 m.

Result

Set the diameter and density, enter a length or a weight, then selectConvert filament.

How much filament is left on the spool?

Weigh the spool with the filament still on it, then subtract the weight of an empty spool of the same type. The difference is the filament left, converted to metres with the diameter, density and price from panel 1.

Enter the three weights, then selectEstimate remaining filament.

How the length-to-weight conversion works

A metre of filament is a cylinder, and a cylinder’s volume is its cross-section multiplied by its length. The cross-section comes straight from the diameter, so once the density of the material is known the weight follows:

weight = π × (diameter ÷ 2)² × length × density

Worked example: 1.75 mm PLA at1.24 g/cm³ sliced for a print that needs100 m. The cross-section isπ × 0.875² = 2.405 mm², so the volume is 2.405 × 100 = 240.5 cm³ and the weight is 240.5 × 1.24 = 298.2 g. That is why a 1 kg spool of 1.75 mm PLA holds roughly 335 m.

The same relation runs backwards for a scale reading: divide the weight by the density to get the volume, then divide by the cross-section to get the length. Nothing in the chain depends on the printer, the slicer version or the material brand — only on the diameter and the density.

Where the two numbers come from in OrcaSlicer

  1. The slicer reports the length. After slicing, the preview and the print summary list the filament used, usually in millimetres or metres and often split per extruder on a multi-colour print.
  2. The profile stores the density. Filament settings carry the density in g/cm³ next to the diameter and the flow ratio, and that same value is what the slicer’s own weight estimates use.
  3. The spool is sold by weight. A “1 kg spool” is the net filament weight; the spool itself adds anywhere from about 120 g to 250 g depending on whether it is plastic, cardboard or a reusable holder.
  4. Convert once per material. Diameter and density are the only inputs that change between prints of the same filament, so one conversion per spool is enough to price every later print.

What the conversion does and does not tell you

  • It is only as good as the density. A nominal 1.24 g/cm³ for PLA is a profile value. Foaming filaments, glass or carbon filled blends and metal-filled compounds sit elsewhere, and a 5% density error is a 5% weight error.
  • Diameter tolerance moves the number twice over.Volume scales with the square of the diameter, so a filament running 1.72 mm instead of 1.75 mm is about 3% lighter per metre.
  • Weight is not a print count. A spool that holds 335 m does not print a fixed number of parts: the same model at a different layer height, infill or support setting can use twice the filament.
  • Cost ignores everything but the price per kg. Filament price is the dominant cost in most prints, but shipping, failed prints, purge waste on multi-colour jobs and electricity are not included.

Frequently asked questions

How many metres are in a 1 kg spool of filament?

It depends on the diameter and the density. 1 kg of 1.75 mm PLA at 1.24 g/cm³ is about 335 m, while the same weight of 2.85 mm PLA is roughly 126 m because the thicker strand holds far more plastic per metre. PETG at 1.27 g/cm³ is slightly shorter than PLA for the same weight.

Should I use 1.75 mm or the diameter printed on the spool?

Use the measured diameter when you have it. Nominal 1.75 mm filament is allowed a tolerance of a few hundredths of a millimetre, and because the area depends on the square of the diameter those hundredths change the grams per metre measurably. If the spool only says 1.75 mm, leave the default in place.

Why does my empty spool weight matter so much?

On a 1 kg spool the empty holder is roughly 12–25% of the gross weight, so guessing it wrong throws the remaining filament off by a similar proportion. Weigh an empty spool of the same brand if you have one; if not, the default of 200 g is a labelled starting point rather than a measurement.

Is the cost figure a quote?

No. It multiplies the weight by the price per kilogram you typed and does not add shipping, tax or the value of the filament lost to failed prints. Use it to compare two spools, not as a billing number.

Does the calculator send my numbers anywhere?

No. The conversion is plain arithmetic that runs in this page, and no value you type is stored, logged or transmitted.

Match the conversion to the material

Density is the one input that changes between materials, and each material guide lists the profile values OrcaSlicer ships with.

PLA spools, temperature and flowMeasure filament in a G-code fileSave and reuse filament profiles