Filament Cost Calculator
A filament cost calculator turns a spool price into the numbers that matter: cost per gram, per metre and per print. Enter price and net weight for instant per-unit economics, convert grams ↔ metres using real filament geometry for any material and diameter, check what a budget buys, or compare two spools for true value.
Net filament weight, not the empty spool.
Sets the density behind the metre conversion.
1.75 mm is standard for most desktop printers.
Slicer reports grams — that is the accurate one.
Fill either this or grams.
$1.55
- Filament used≈ 20.79 m of filament
- 62.0 g
- Share of spool
- 6.2%
- Price per gram
- $0.025
- Price per metre
- $0.075
- Grams per metreAt 1.24 g/cm³
- 2.98
- Length on the spool
- 335 m
Data last verified 30 September 2026.
How it works
- 01
Describe the spool
Price and net weight (pick 250 g, 500 g, 1 kg or 2 kg) plus the material and diameter — that instantly yields price per gram and per metre.
- 02
Choose your question
Cost of one print from the slicer’s gram estimate, how many grams and metres your budget buys, or which of two spools is genuinely better value.
- 03
Convert grams ↔ metres physically
Length conversions use real filament geometry: a 1.75 mm PLA strand is π × 0.875² mm² × 1.24 g/cm³ ≈ 2.99 g per metre — no rough rules of thumb.
Metre conversions assume nominal diameter and published material density; actual filament can vary ±0.05 mm in diameter, shifting length figures by a few percent. Cost per gram uses the net weight you enter — weigh the spool for precision.
Frequently asked questions
How much does filament cost per gram?
Divide the spool price by its net weight. A $25 kg spool is $0.025/g; premium carbon-filled at $45 for 750 g is $0.06/g. As a rule of thumb, budget PLA runs 2–3¢/g, quality branded PLA 2.5–4¢/g, and engineering or composite filaments 6–15¢/g.
How many metres are on a 1 kg spool of PLA?
About 335 m for 1.75 mm PLA (density 1.24 g/cm³ gives ≈ 2.99 g per metre). PETG is slightly heavier per metre (~306 m/kg), ABS lighter (~399 m/kg). This calculator does the geometry properly for any diameter and material you pick.
How do I convert filament grams to metres?
Metres = grams ÷ (π × (d/2)² × density), with d in mm and density in g/cm³. For 1.75 mm PLA that is grams ÷ 2.99. The reverse — multiplying metres by 2.99 — gives the grams a slicer’s length estimate implies.
Is a bigger spool always cheaper per gram?
Not always. Bulk 2 kg and 5 kg spools usually undercut 1 kg prices by 10–25% per gram, but specials on 800 g "value" spools sometimes win — and filament you never use (or that absorbs moisture while you finish a 5 kg brick) costs you the difference. Use the compare mode before committing.
What does a typical print cost in filament?
A small 20 g print costs 40–80¢ of PLA; a 100 g cosplay part $2.50–$4; a full-plate batch of 30 miniatures at 7 g each is around $5–$8 of filament. Add machine time, electricity and failures with the Printing Cost Calculator for the true figure.
Why weigh filament instead of trusting the spool label?
Net weights on budget spools drift by a few percent, and some are noticeably under-filled. A kitchen scale reading gives you the honest price per gram — the calculator then makes every print cost follow it.
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