Percent Scale Calculator — Scale Ratios & Sizes to Scale %
For Cura · PrusaSlicer · Bambu Studio · Chitubox · Lychee
A free percent scale calculator for 3D-print slicers and scale model making. Enter a scale ratio (like 1:48) or two sizes (current mm → target mm), and read the exact percentage to type into your slicer’s Scale field. Works both directions: you can also enter a percentage result on the calculator page directly, or start from either size.
Precision Scale Conversion Calculator
How to use this in your slicer
The percentage on the “scale %” line is the number to enter in the Scale field of your slicer. In Cura and Bambu Studio it lives on the left toolbar under the “Scale” icon; in PrusaSlicer it’s on the right in the Object Manipulation panel; in Chitubox and Lychee it’s the “Scale” input in the model transform controls. Every one of these tools accepts a percentage where 100 = original size. Uniform scaling on X, Y, and Z is almost always what you want — scaling only one axis distorts the model.
Two workflow patterns:
- Ratio-based: you want the print at a specific scale (say 1:35). Type
35into the Scale field above. The tool shows 2.86% — that’s what you enter in the slicer. - Size-based: you want the print at a specific finished size. Enter the STL’s current size in Real Size, the size you want in Scaled Size, and the calculator solves for the ratio and percentage.
Common Scale → Scale % Reference
Precomputed percentages for the ratios most model builders and miniature painters actually print at. Numbers computed exactly from 100 ÷ ratio.
| Scale | Scale % | Common use |
|---|---|---|
| 1:12 | 8.33% | Large action figures, dolls |
| 1:18 | 5.56% | Premium diecast cars |
| 1:24 | 4.17% | Car model kits |
| 1:35 | 2.86% | Military armor |
| 1:48 (O) | 2.08% | Aircraft, US O gauge |
| 1:56 (28mm) | 1.79% | Warhammer, wargaming |
| 1:72 | 1.39% | Aircraft, small armor |
| 1:87 (HO) | 1.15% | Model railroads |
| 1:100 (15mm) | 1% | Architecture, mass battles |
| 1:144 | 0.69% | Airliners, Gunpla HG |
| 1:160 (N) | 0.63% | Small-space railroads |
How far can you shrink a model before it loses detail?
There is a real floor. A resin printer resolves finer detail than FDM, but both have a resolution limit — features like straps, buckles, eyes, and thin edges start disappearing when they drop below your printer’s XY pixel size. As a rough guide, shrinking a miniature much below about 70–75% of its original size is where detail loss becomes noticeable, and going below 50% usually needs sculpt-side rework rather than raw scaling. For a longer walkthrough with numbers, see the guide on how to scale STL files for 3D printing.
Frequently Asked Questions
What percentage do I enter in my slicer to scale a model?
Divide 100 by the target scale ratio. For 1:48 that's 100 ÷ 48 = 2.08%. The calculator above does this automatically — type the ratio and read the "scale %" line. Enter that number in Cura, PrusaSlicer, Bambu Studio, Chitubox, or Lychee's scale field.
How do I scale a 100 mm STL to fit a specific size in my slicer?
Divide the size you want by the size you have, then multiply by 100. For a 100 mm STL you want at 65 mm, that's 65 ÷ 100 × 100 = 65%. You can also enter both sizes into the calculator above (Real Size = current, Scaled Size = target) and read the resulting scale factor and percentage.
What percentage is 1:35 to 1:48?
Going from 1:35 down to 1:48 is 35 ÷ 48 = 72.9%. To convert one scale ratio to another, divide the "from" ratio by the "to" ratio. The result is the slicer percentage you apply to the STL that was authored at the "from" scale.
What percentage is 28mm to 32mm?
Wargaming "28mm" is nominally 1:56 (eye-height) and "32mm heroic" is roughly 1:52. Scaling a 28mm miniature up to 32mm is about 32 ÷ 28 = 114.3%. Studios vary though — some measure to the top of the head, some to the eyes — so always test-print a small feature before committing to a full army.
Can I shrink a miniature too much before it loses detail?
Yes. Miniatures printed below about 70% of their original size start losing fine detail like straps, buckles, and eyes because features drop below your printer's XY resolution. A resin printer resolves finer detail than FDM, but even resin has a limit. If you're shrinking a lot, see our guide on scaling STL files for 3D printing.
Does the slicer scale field want a percentage or a decimal?
Cura, PrusaSlicer, and Bambu Studio all accept a percentage in the scale field (100 = original size, 50 = half). Some slicers also expose absolute XYZ dimensions in mm as an alternative — either works, but the percentage is the field this calculator outputs.
Keep Exploring
All scales compared · Scaling STL files guide · Resin printing for miniatures · Full scale calculator