3D printing filament is sold in spools classified by weight. They are often in 500-gram or 1-kilogram spools, although there are both bigger and smaller options. This is likely the most convenient unit of measurement in terms of sales and logistics.
Unfortunately, it’s easier to estimate how long a spool would last if you knew exactly how long the filament is. Here is a handy way to calculate for the meters of filament in your spool given its weight.
How to Calculate The Length?
Based on our calculations, there are around 335 meters of filament in a 1-kilogram spool of PLA filament with a diameter of 1.75 millimeters. Note that these calculations assume that the diameter of the filament is perfectly consistent throughout its length.
Below is how we calculate the length. The calculation is : H=4W/(πρD*D)
H: filament length
W: filament weight per roll
π：3.14
ρ: filament weight
D: filament diameter
Take 1kg/roll 1.75mm PLA filament for example.
Here is a summary of filaments’ weight.
1kg 1.75mm PLA filament length is around 335 meters.
1kg 1.75mm ABS filament length is around 400 meters.
1kg 1.75mm TPU filament length is around 335 meters.
1kg 1.75mm PETG filament length is around 328 meters.
1kg 2.85mm PLA filament length is around 126 meters.
1kg 2.85mm ABS filament length is around 151 meters.
1kg 2.85mm TPU filament length is around 126 meters.
1kg 2.85mm PETG filament length is around 123 meters.
This approach may be used for any filament or spool SKU. You can also use the same calculations to estimate the length of leftover filament in a spool that has been partially consumed if you have a weighing scale at home. Just make sure to account for the weight of the empty spool.
More filament length calculations are below.
| | π | ρ | D | W | H |
| 1kg 1.75mm PLA(1.24) | 3.14 | 1.24 | 1.75 | 1 | 335 |
| 0.5kg 1.75mm PLA(1.24) | 3.14 | 1.24 | 1.75 | 0.5 | 168 |
| 5kg 1.75mm PLA(1.24) | 3.14 | 1.24 | 1.75 | 5 | 1677 |
| 1kg 2.85mm PLA(1.24) | 3.14 | 1.24 | 2.85 | 1 | 126 |
| 1kg 1.75mm ABS(1.04) | 3.14 | 1.04 | 1.75 | 1 | 400 |
| 0.5kg 1.75mm ABS(1.04) | 3.14 | 1.04 | 1.75 | 0.5 | 200 |
| 5kg 1.75mm ABS(1.04) | 3.14 | 1.04 | 1.75 | 5 | 2000 |
| 1kg 2.85mm ABS(1.04) | 3.14 | 1.04 | 2.85 | 1 | 151 |
| 1kg 1.75mm TPU(1.24) | 3.14 | 1.24 | 1.75 | 1 | 335 |
| 0.5kg 1.75mm TPU(1.24) | 3.14 | 1.24 | 1.75 | 0.5 | 168 |
| 1kg 2.85mm TPU(1.24) | 3.14 | 1.24 | 1.75 | 5 | 1677 |
| 5kg 1.75mm TPU(1.24) | 3.14 | 1.24 | 2.85 | 1 | 126 |
| 1kg 1.75mm PETG(1.27) | 3.14 | 1.27 | 1.75 | 1 | 328 |
| 0.5kg 1.75mm PETG(1.27) | 3.14 | 1.27 | 1.75 | 0.5 | 164 |
| 5kg 1.75mm PETG(1.27) | 3.14 | 1.27 | 1.75 | 5 | 1638 |
| 1kg 2.85mm PETG(1.27) | 3.14 | 1.27 | 2.85 | 1 | 123 |
