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STL Scale Inspector
Know the Exact Size Before You Print

Stop wasting filament and resin on mis-sized files. Pick the scale your STL was modeled in and the scale you need — get the exact percentage to type into your slicer. Tested with digital calipers on a Bambu Lab A1 Mini.

No uploads, no accounts, no cookies. Use the scale math below, or drop an STL into the file inspector to read its real millimetre and inch dimensions on your own hardware.

Current STL Scale

Scale You Want

Eye Level (Standard)

Top of Head

Material compensation

Add a slight percentage bump for cooling contraction in PLA or PETG.

Type this into your slicer

114.3%

28mm → 32mm · Eye Level

32.0 ÷ 28.0 × 100

Estimate Cost

Tested on Bambu A1 Mini•My Methodology

Conversion logic assumes a 175 human baseline. Eye Level measures to 160cm. Top of Head accounts for hair and helmets at 175cm.
Tip: Always use Uniform Scaling (lock X, Y, Z axes) in your slicer to avoid model distortion.

File inspector · no upload

Check what size the STL actually is

Drop a file in to read its bounding box in millimetres and inches, flag a likely inches-vs-mm mismatch, and turn any target height into the exact scale percentage for your slicer. The STL is parsed in this tab and never uploaded.

Drop an STL for measurement

Binary or ASCII. Reads the real X / Y / Z bounds, reports inches alongside millimetres, and calculates the percentage needed to reach a target height.

Choose STL file

How I check scale before every print

1
Find the sculptor's scale
Check what scale the file was modeled in — usually listed on the download page or store page of the creator.
2
Copy the exact percentage
Eyeballing percentages leads to distorted proportions. The inspector gives exact mathematical output verified with physical calipers.
3
Paste and lock axes
Enter the percentage into your slicer, lock X, Y, and Z to uniform scaling, and slice.