This filament

2.98 g per metre335 m in 1kg

50 m weighs: 149 g
300 g is: 101 m
Left on the spool: 270 g, about 91 m

Densities are typical published figures; filled materials vary more. How much filament is on a 1kg spool?

How it is worked out

One metre of filament is a thin cylinder, so its weight is its cross-section times its length times the material's density.

Cross-section: π × (diameter ÷ 2)². For 1.75mm that is 2.405 mm², so one metre is 2.405 cm³ of plastic.
Density: grams per cm³, which differs by material: PLA is about 1.24, PETG 1.27, ABS 1.04.
Metres to grams: length × cross-section × density.
Grams to metres: weight ÷ the grams in one metre.
What is left: the scale reading minus the empty spool's weight is the filament, in grams, which converts to metres the same way.
Diameter matters: 2.85mm filament has 2.65 times the plastic per metre of 1.75mm, so a figure for one never works for the other.

A worked example

These are the figures the calculator opens with: 1.75mm PLA at 1.24 g/cm³, and a spool that reads 520g on a scale with a 250g empty spool.

One metre	2.405 mm² × 1.24	2.98 g
In 1kg	1,000 ÷ 2.98	335 m
50 metres	50 × 2.98	149 g
300 grams	300 ÷ 2.98	101 m
Filament on the spool	520g − 250g	270 g
Left, in metres	270 ÷ 2.98	about 91 m

The same 1kg of PLA at 2.85mm is about 126 metres, because each metre holds 2.65 times as much plastic.

Common questions

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

About 335 metres of 1.75mm PLA, 327 of PETG and 400 of ABS. At 2.85mm, PLA is about 126 metres. The calculator works it out for any material and diameter.

How many grams of filament are in a 1kg roll?

1,000 grams of filament: the 1kg on the label is the filament alone, and the empty spool is extra. Weigh an empty spool once so you can take it off a scale reading.

How much can you print with 1kg of filament?

Divide 1,000g by the grams your slicer gives for one print, then allow for purge, supports and prints that fail. A 20g model is about 50 from a spool on paper, and fewer in practice.

What diameter is my filament?

Almost all filament is 1.75mm; some printers, including older Ultimaker and Lulzbot models, use 2.85mm, often sold as 3mm. The spool's label says which.

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

Weigh it, take off the weight of an empty spool of the same brand, and what remains is the filament in grams. Convert to metres to compare with what your slicer says a print needs.

Why does the material matter?

Because density differs: a metre of ABS weighs about a fifth less than a metre of PLA. A "multiply metres by three" rule works for PLA and overstates ABS by about 20%.

How much filament is on a 1kg spool? · 3D print cost calculator · Where your filament actually goes

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