How do you calculate the volume of an STL file?

Each triangle forms a tetrahedron with the origin; adding up their signed volumes (a · (b × c) ÷ 6) gives the exact volume of a closed mesh. This is the divergence theorem applied to a triangle mesh.

Why is the printed weight lower than volume × density?

Prints are not solid. Slicers print solid walls and a sparse infill inside, so a typical part uses 30–70% of its solid volume in plastic. The calculator models walls and infill separately.

Home / STL volume calculator

STL volume calculator

Get the exact volume of an STL model in cubic centimetres, its surface area and bounding box, and what it weighs when printed in any material — calculated on your device in a fraction of a second.

Drop an STL file anywhere100% in-browser · nothing uploaded

File: — ·
Size (X × Y × Z): —
Volume: —
Surface area: —
Triangles: —
Mesh check: —
Build volume: —

Cost estimate

Cost per part—

Price per part—

Weight—

Filament—

Print time—

Energy—

Cost	How	Amount	Share

Open STL file

File units

Scale (%)

Material

Density (g/cm³)

Price per kg

Infill

Wall thickness (mm)

Filament

Supports & waste (%)

Printer, time & electricity

Printer type

Print time (h)

Average watts

Electricity per kWh

Machine wear per hour

Labor, failures & markup

Labor (minutes)

Labor per hour

Failure buffer (%)

Markup (%)

Quantity

Currency

How the volume is calculated

An STL describes a closed surface made of triangles. For every triangle with corners a, b and c, the calculator adds the signed volume of the tetrahedron it forms with a reference point: a · (b × c) ÷ 6. Volumes outside the model cancel out, leaving the exact enclosed volume. This only works for watertight meshes, so the calculator also checks every edge and warns you when the mesh has holes.

Solid weight per cm³

Material	Density	Solid weight of 10 cm³
PLA	1.24 g/cm³	12.4 g
PETG	1.27 g/cm³	12.7 g
ABS	1.04 g/cm³	10.4 g
ASA	1.07 g/cm³	10.7 g
TPU	1.21 g/cm³	12.1 g
Nylon (PA)	1.14 g/cm³	11.4 g
Polycarbonate (PC)	1.2 g/cm³	12.0 g
Standard resin	1.15 g/cm³	11.5 g

Printed parts weigh less than their solid volume because of infill. The weight in the results above uses your wall thickness and infill; see how much filament a print uses for the details.

Volumes of common test shapes

Model	Size (mm)	Volume	Surface area
20 mm calibration cube	20 × 20 × 20	8.00 cm³	24.0 cm²
50 mm sphere	50 × 50 × 50	65.38 cm³	78.5 cm²
70 mm twisted planter (sample)	71 × 71 × 70	48.27 cm³	326.0 cm²
50 mm ring (torus)	50 × 50 × 10	9.83 cm³	39.4 cm²
100 × 100 × 3 mm plate	100 × 100 × 3	30.00 cm³	212.0 cm²

FAQ

What unit is the volume in?

Cubic centimetres (cm³), assuming the STL is in millimetres. 1 cm³ = 1,000 mm³ = 1 ml. If your model was exported in inches or metres, change File units.

My volume looks wrong — why?

Usually the units (a model in metres looks 1,000 times too small), or holes in the mesh. Check the mesh check line: open edges mean the volume is unreliable.