Tech & PC
How much 3D printer filament do you need for a print?
Filament length, spool usage and material cost from your slicer weight estimate.
Quick answer
Slicers already know the answer in grams — this tool converts that to **meters of filament** and **cost per print**. An **85 g** PLA part on **1.75 mm** filament is roughly **28 meters** (PLA density 1.24 g/cm³) and uses **8.5%** of a 1 kg spool. At **8/kg** that is about **.53** in material — supports and brim included if your slicer total includes them.
Filament length
28 m
- Share of 1 kg spool
- 8.5 %
- Material cost
- .53
Use the weight Cura, PrusaSlicer or Bambu Studio shows before printing. Length = volume ÷ cross-section; supports and brim are already in the slicer number if you left them enabled.
How it works
Formula: **length (m) = (grams ÷ density) ÷ (π × (diameter/2)²)** with consistent units. PETG and ABS change length slightly at the same weight because density differs. Compare PLA spools when buying — bulk 1 kg reels beat 250 g samples on shipping per gram.
Frequently asked questions
How many meters of filament in 1 kg PLA?+
About 330 m for 1.75 mm PLA (1.24 g/cm³). PETG is slightly shorter per kg (~320 m) because it is denser. Use the calculator with 1000 g to see your material.
Where do I get the gram estimate?+
Cura, PrusaSlicer, Bambu Studio and Orca show filament weight in the preview before you slice to G-code. Use that number — do not guess from STL volume unless you enjoy failed spool math.
1.75 mm vs 2.85 mm filament?+
Thicker filament feeds faster on large nozzles but weighs the same per meter of plastic deposited — cross-section area changes, so meters per gram drop. Pick your diameter in the calculator to match the spool.
Should I include supports in the weight?+
Yes if they will be printed — slicer totals include supports, brim and raft when enabled. Toggle them off in the slicer first if you want net part weight only.
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