How long is 1 kg of PLA filament?
A 1 kg spool of 1.75 mm PLA is about 335.3 m long; a kilogram of 2.85 mm PLA is about 126.4 m. That uses a density of 1.24 g/cm³. Convert any weight or length below.
PLA grams ↔ meters converter
How much PLA is left on my spool?
PLA length and weight at a glance
| Filament | Cross-section | Per kg | 1 m weighs | 1 g is |
|---|---|---|---|---|
| 1.75 mm | 2.405 mm² | 335.3 m | 2.98 g | 33.5 cm |
| 2.85 mm | 6.379 mm² | 126.4 m | 7.91 g | 12.6 cm |
Which density this page uses
Datasheets for plain PLA cluster around 1.24 g/cm³; filled and specialty grades (silk, matte, wood, metal or carbon fill) range from about 1.17 to over 1.3 g/cm³, so check the label if you print those. Every number on this page is computed from 1.24 g/cm³; if your spool lists a different density, choose the closest material or scale the result: length is inversely proportional to density, so a material 3% denser gives 3% fewer meters per kilogram.
Length of common PLA spool sizes
| Net weight | 1.75 mm | 2.85 mm |
|---|---|---|
| 250 g | 84 m | 32 m |
| 500 g | 168 m | 63 m |
| 750 g | 251 m | 95 m |
| 1 kg | 335 m | 126 m |
| 2 kg | 671 m | 253 m |
| 3 kg | 1,006 m | 379 m |
| 5 kg | 1,676 m | 632 m |
Net weight is the filament only — the empty spool comes on top. Not every brand sells every size in PLA; the table simply converts the weight on the label.
PLA cost per meter and per gram
| Spool price | Per gram | Per m (1.75) | Per m (2.85) | 10 m (1.75) |
|---|---|---|---|---|
| $15.00 / kg | 1.5¢ | 4.5¢ | 11.9¢ | $0.45 |
| $20.00 / kg | 2.0¢ | 6.0¢ | 15.8¢ | $0.60 |
| $25.00 / kg | 2.5¢ | 7.5¢ | 19.8¢ | $0.75 |
| $35.00 / kg | 3.5¢ | 10.4¢ | 27.7¢ | $1.04 |
Material only. A full print also pays for electricity, machine wear and failed prints — see 3D printing cost per gram for worked examples, or drop an STL into the PLA print cost calculator.
How diameter tolerance changes the length
Filament is sold by weight, so a spool that runs slightly thick holds fewer meters, and one that runs thin holds more. Length scales with 1 ÷ diameter², so small diameter errors matter roughly twice as much in length:
| Tolerance | Diameter | 1 kg is | Length change |
|---|---|---|---|
| 1.75 ± 0.02 mm | 1.73–1.77 mm | 328–343 m | −2.2% / +2.3% |
| 1.75 ± 0.05 mm | 1.70–1.80 mm | 317–355 m | −5.5% / +6.0% |
| 2.85 ± 0.05 mm | 2.80–2.90 mm | 122–131 m | −3.4% / +3.6% |
Good filament is typically specified at ±0.02–0.03 mm and budget filament at ±0.05 mm. Your slicer assumes the nominal diameter, so a consistently thick spool also over-extrudes by the same percentage; if you measure an average diameter well away from nominal, enter it in the slicer's filament settings.
PLA compared with other filaments
| Filament | g/cm³ | 1 kg, 1.75 mm | vs PLA |
|---|---|---|---|
| PLA | 1.24 | 335 m | — |
| PETG | 1.27 | 327 m | −2% |
| ABS | 1.04 | 400 m | +19% |
| TPU | 1.21 | 344 m | +2% |
| ASA | 1.07 | 389 m | +16% |
| Nylon (PA) | 1.14 | 365 m | +9% |
About PLA spools
PLA is the reference material for most filament numbers you see online, which is why "335 meters per kilogram" has become a rule of thumb. It only holds for 1.75 mm filament at about 1.24 g/cm³ — a silk or matte PLA with a different density changes the answer by several percent.
Because PLA absorbs little moisture, weighing a used spool is a reliable way to find how much is left: subtract the empty spool weight and convert the grams with the calculator above. Large 2–5 kg spools save money per kilogram but usually need a bigger spool holder or an external stand.
The formula, worked for PLA
length = mass ÷ (density × π × (diameter ÷ 2)²)
1,000 g ÷ 1.24 g/cm³ = 806.5 cm³ = 806,452 mm³ of plastic. A 1.75 mm filament has a cross-section of π × 0.875² = 2.405 mm², so the length is 806,452 ÷ 2.405 = 335,284 mm, or 335.3 m. With 2.85 mm filament (6.379 mm²) it is 126.4 m.
Read how much filament a print uses to estimate the grams a model needs, or go back to the filament length calculator for every material.
FAQ
How long is 1 kg of PLA filament?
About 335 m of 1.75 mm PLA or 126 m of 2.85 mm filament, at a density of 1.24 g/cm³.
How much does 1 meter of PLA filament weigh?
About 2.98 g for 1.75 mm and 7.91 g for 2.85 mm, so 10 m of 1.75 mm PLA is about 29.8 g.
How many meters are on a 250 g or 5 kg spool of PLA?
A 250 g spool of 1.75 mm PLA holds about 84 m; a 5 kg spool about 1,676 m. In 2.85 mm the same spools hold about 32 m and 632 m.
What does PLA filament cost per meter?
At $20.00 per kg, 1.75 mm PLA costs 6.0¢ per meter and 2.0¢ per gram; 2.85 mm costs 15.8¢ per meter.