How is the surface area calculated?
The area of every triangle in the mesh is calculated from its three vertex coordinates. The individual triangle areas are then added together.
CAD & 3D
Mesh Surface Area Calculator
Calculate the surface area of STL, OBJ, and 3MF models online. Measure total mesh area locally in your browser without uploading files.
Tool
Mesh Surface Area Calculator
Calculate the surface area of STL, OBJ, and 3MF models online. Measure total mesh area locally in your browser without uploading files.
This tool runs in your browser. Your input is processed locally and is not uploaded.
About this Tool
Use this free online Mesh Surface Area Calculator to measure the total surface area of STL, OBJ, and 3MF models. Load a 3D file, select the correct model unit, inspect the mesh statistics, and calculate the combined area of all triangles in the model. The result can support coating, painting, plating, material, heat-transfer, and manufacturing estimates. Processing takes place directly in your browser, so your file remains on your device.
Examples
- cube-ascii.stl
- multi-group.obj
- multi-object.3mf
Frequently Asked Questions
Does the mesh need to be watertight?
No. Surface area can also be calculated for open meshes. However, duplicated, overlapping, internal, or unintended faces may increase the result.
Which units are used for the result?
The result is expressed in squared units based on the selected model unit, such as square millimeters, square centimeters, square meters, or square inches.
Why does the file format matter for units?
STL and many OBJ files do not reliably define a physical unit. 3MF can store unit information, but you should still verify that the detected scale matches the intended model dimensions.
Can this calculate only the outside surface?
The basic calculation includes every triangle stored in the mesh. Internal shells, hidden faces, overlapping geometry, and separate components are included unless they are removed or filtered first.
Can I use the result to estimate paint or coating?
Yes, as an approximate geometric basis. Real material use also depends on coverage rate, layer thickness, surface texture, overspray, absorption, and application losses.
Is my 3D file uploaded?
No. The surface area is calculated locally in your browser.