How Much Filament Is Left? Spool Weight to Length Calculator
Put the spool on a kitchen scale, choose the brand and material, and read off the grams, meters and percent remaining.
Your measurements
Weigh your spool and pick the material and brand. Everything updates as you type.
Filament
Typical density for this material. Use your filament's data sheet if it gives one.
Most printers use 1.75 mm; some, such as Ultimaker, use 2.85 mm. It is printed on the spool label.
Spool
Reusable spool with cardboard core as shipped: 233–250 g reported (midpoint used). The bare reusable spool is about 208–216 g and older gen-1 spools about 251–264 g.
Put the spool, with its filament, on a kitchen scale.
Rough fill level
Electricity (optional)
Typical average draw, estimated. A plug-in power meter gives your printer's real figure.
Results
PLA (Polylactic Acid) left on the spool
m
= 1100.1 ft
About 100% of a 1000 g spool. Compare this with the filament length your slicer shows for the print.
- Filament weight
- 1000g
- = 35.27 oz
- Scale weight minus 242 g empty spool
- Electricity for the print
- $0.14
- 8 h on Bambu Lab P1S (estimated draw)
Check before you cut (2)
- Empty spools from this brand vary by about ±9 g, so the remaining length could be off by about ±3 m. Weigh one of your own empty spools and enter it for an exact figure.
- 1.24 g/cm³ is a typical density for PLA (Polylactic Acid). Brands differ by a few percent, and the length changes by the same percentage. Use the density on your filament's data sheet if you have it.
How this was calculated
Weight to length, with your numbers.
How this was calculated
Weight to length, with your numbers.
Step 1: Subtract the empty spool
W_net = W_total − W_spool
= 1242 g − 242 g
= 1000 g of filamentBambu Lab (reusable spool, as shipped) spools are taken as 242 g (233–250 g reported). A ±9 g spread changes the answer by about 3 m.
Step 2: Cross-section of 1.75 mm filament
A = π × (d ÷ 20)²
= π × (0.0875 cm)²
= 0.024053 cm²The diameter in millimetres is halved and converted to centimetres so the units match the density in g/cm³.
Step 3: Length from weight
L = W_net ÷ (ρ × A × 100)
= 1000 g ÷ (1.24 g/cm³ × 0.024053 cm² × 100)
= 335.3 mDividing by density and cross-section gives centimetres; ÷100 gives metres. A density that is 2% off makes the length 2% off.
Step 4: Electricity for the print
Cost = watts × hours ÷ 1000 × price per kWh
= 110 W × 8 h ÷ 1000 × $0.16
= $0.14110 W is an estimated average for the Bambu Lab P1S. A plug-in power meter gives your printer's real figure.
Sources
PLA (Polylactic Acid): density
EstimatedTypical value, not from a maker's document. Measure or confirm before relying on it.
Bambu Lab (reusable spool, as shipped): empty spool weight
From sourceFrom a published reference; brands and batches vary. Checked 23 Oct 2026.
- LayerTune: empty filament spool weights by brand (community readings) (Bambu Lab reusable spool + cardboard core, as shipped: 233–250 g (source: filamentcalcs.com)), opened 23 Oct 2026
In short
Scale reading − empty spool = filament grams. 1 kg of 1.75 mm PLA is about 335.3 m; an empty Bambu Lab (reusable spool, as shipped) spool is about 242 g.
Every brand and material preset can also be loaded from a shared link.
Empty spool weight by brand
Subtract the empty spool from your scale reading. Spools from the same brand vary by several grams, so weighing one of your own empties is always the most accurate option.
| Brand | Empty spool | Spool type | Basis |
|---|---|---|---|
| Bambu Lab (reusable spool, as shipped) | 242 g (233–250 g reported) | Plastic | Community readings |
| eSun (plastic spool) | 220 g (200–240 g reported) | Plastic | Community readings |
| eSun (cardboard spool) | 150 g (150–165 g reported) | Cardboard | Community readings |
| Polymaker (1 kg cardboard spool) | 140 g (133–147 g per maker) | Cardboard | Maker's figure |
| Prusament (plastic sides + cardboard core) | 200 g (192–207 g reported) | Plastic | Community readings |
| Hatchbox (plastic spool) | 227 g (210–244 g reported) | Plastic | Community readings |
| Sunlu (plastic spool) | 161 g (133–189 g reported) | Plastic | Community readings |
| Overture (cardboard spool) | 163 g (one reading) | Cardboard | Single community reading |
| Overture (plastic spool) | 204 g (171–237 g reported) | Plastic | Community readings |
| Creality (plastic spool) | 140 g (one reading) | Plastic | Single community reading |
| Inland / Micro Center (plastic spool) | 220 g (200–240 g typical) | Plastic | Estimate |
| Duramic 3D (cardboard spool) | 140 g (130–150 g typical) | Cardboard | Estimate |
| Eryone (cardboard spool) | 140 g (130–150 g typical) | Cardboard | Estimate |
| Amazon Basics (plastic spool) | 220 g (200–240 g typical) | Plastic | Estimate |
| MasterSpool / 3D-printed spool | 180 g (estimate) | MasterSpool | Estimate |
Sources for each figure are listed on the brand pages and in the empty spool weight chart. "Estimate" means no published weight was found.
Meters per kilogram for common filaments
Length depends only on density and diameter. Densities marked typical are generic values; a specific brand can be a few percent off.
| Material | Density | 1 kg at 1.75 mm | 1 kg at 2.85 mm |
|---|---|---|---|
| PLA (Polylactic Acid) | 1.24 g/cm³ (typical) | 335.3 m | 126.4 m |
| PETG (Polyethylene Terephthalate Glycol) | 1.27 g/cm³ (typical) | 327.4 m | 123.4 m |
| ABS (Acrylonitrile Butadiene Styrene) | 1.04 g/cm³ (typical) | 399.8 m | 150.7 m |
| ASA (Acrylonitrile Styrene Acrylate) | 1.07 g/cm³ (typical) | 388.6 m | 146.5 m |
| TPU 95A (Flexible Elastomer) | 1.21 g/cm³ (typical) | 343.6 m | 129.5 m |
| PLA-CF (Carbon Fiber PLA) | 1.22 g/cm³ | 340.8 m | 128.5 m |
| PETG-CF (Carbon Fiber PETG) | 1.25 g/cm³ | 332.6 m | 125.4 m |
| PA6-CF (High Tensile Nylon 6 CF) | 1.09 g/cm³ | 381.4 m | 143.8 m |
| PC (Polycarbonate) | 1.2 g/cm³ (typical) | 346.5 m | 130.6 m |
| Bronze Metal Fill PLA (colorFabb bronzeFill) | 3.9 g/cm³ | 106.6 m | 40.2 m |
All 40 materials are in the filament density chart.
Worked example: a full Bambu Lab spool of PLA
The same three steps the calculator runs, for PLA (1.24 g/cm³) on a Bambu Lab (reusable spool, as shipped) spool.
Step 1: Subtract the empty spool
W_net = W_total − W_spool
= 1242 g − 242 g
= 1000 g of filamentBambu Lab (reusable spool, as shipped) spools are taken as 242 g (233–250 g reported). A ±9 g spread changes the answer by about 3 m.
Step 2: Cross-section of 1.75 mm filament
A = π × (d ÷ 20)²
= π × (0.0875 cm)²
= 0.024053 cm²The diameter in millimetres is halved and converted to centimetres so the units match the density in g/cm³.
Step 3: Length from weight
L = W_net ÷ (ρ × A × 100)
= 1000 g ÷ (1.24 g/cm³ × 0.024053 cm² × 100)
= 335.3 mDividing by density and cross-section gives centimetres; ÷100 gives metres. A density that is 2% off makes the length 2% off.
Filament remaining: common questions
Scale method, spool weights and accuracy.
How do I tell how much filament is left on a spool?
Weigh the spool on a kitchen scale, subtract the weight of the empty spool, and convert the grams that remain to length using the filament's density and diameter. The calculator does the conversion and shows the result in meters, feet and percent of a full spool.
How many meters are in a 1 kg spool of PLA?
About 335.3 m for 1.75 mm PLA at a typical density of 1.24 g/cm³, and about 126.4 m for 2.85 mm. Brands differ by a few percent because their densities differ.
What if my spool brand is not listed or I am not sure of its empty weight?
Weigh an empty spool of the same brand, tick 'I weighed an empty spool myself' and enter the weight. The result then uses your measurement instead of the reference value, which removes the biggest source of error.
Is the result exact?
It is as exact as the two inputs it depends on: the empty spool weight and the filament density. A 10 g error in the empty spool weight is about 3 m of 1.75 mm PLA. The calculator warns when it is using an estimated value.