How-To · Updated July 2026

Slicer Scale Settings: Cura vs PrusaSlicer vs Bambu Studio

Every slicer has a field somewhere for resizing a model before you print it, and every one of them treats "100%" the same way — the model's original, as-imported size — even though that field lives in a different spot and looks a little different depending on the program. This guide covers where Cura, PrusaSlicer, and Bambu Studio each put their scale/transform control, how a percentage relates to a scale ratio, and the difference between scaling a model uniformly versus stretching one axis on its own. It also covers the extra wrinkle resin slicers like Chitubox and Lychee add to the same basic idea. It's written for scale modelers and miniature printers who've found a great STL authored at the wrong scale and want to resize it correctly instead of guessing at a percentage.

As an Amazon Associate, Easy Scale Calc earns from qualifying purchases. We may also earn commissions from other affiliate partners, at no extra cost to you.

How to choose

There are two related pieces of math behind a scale field, and which one applies depends on what you're starting from. Scaling a full-size (1:1) model down to a single named scale uses percentage = 100 ÷ ratio — a model at real-world size that you want printed at 1:48 needs 100 ÷ 48 = 2.08% entered in the scale field. Converting a model that's already at one named scale to a different one uses the ratio you have divided by the ratio you want instead: a model authored at 1:48 that you want printed at 1:35 needs 48 ÷ 35 = 137.1%. And when there's no named scale involved at all — you just want to shrink or grow a model relative to whatever size it currently is — that's a plain ratio of target size to current size, like 66.7% to reduce something to two-thirds of what it currently is. In every case, 100% always means the model's original, as-imported size — not necessarily the "correct" size, just whatever size the STL happens to be at when you import it. If you'd rather not do the division by hand, the percent scale calculator on this site converts a ratio — or a real-world size versus a target size — straight into the percentage to type into whichever slicer you're using. What matters more than which slicer you're in is whether the scale is locked uniformly across X, Y, and Z or set per axis — uniform keeps proportions correct and is the default in every slicer covered here, while per-axis scaling is for a narrow set of intentional cases rather than a general-purpose tool. Where the slicers genuinely differ is presentation: how the scale/transform control is laid out, whether it opens showing a percentage or an absolute millimeter dimension by default, and how obviously the uniform-scaling lock is exposed — none of which changes the underlying math, just how many clicks it takes to get there.

Our picks

Elegoo Mars Resin 3D Printer — for confirming a rescale actually worked$$

Chitubox and Lychee handle scaling the same general way FDM slicers do — a percentage or size field on the selected model, usually with a uniform-scaling lock — but resin workflows add a sequencing detail: supports typically get generated after the model is placed and sized, so a model you rescale after adding supports usually needs those supports regenerated to match. An entry-level MSLA printer like this is a practical way to check whether a rescale held up: print the resized model and measure it against your target dimension before committing a full plate to it. It's sized more for miniatures and small parts than large terrain pieces, which lines up with the kind of scale change (28mm to 32mm heroic, or fitting a bust to a smaller base) this guide is mostly about.

Elegoo Mars Resin 3D Printer on Amazon →

Elegoo Standard Resin (Grey) — for print-testing a scale change$

Once you rescale a model by more than a small amount, the only real way to know whether fine detail survived is to print it, and a dependable standard resin tends to be a sensible choice for that kind of test rather than a specialty formula you're also troubleshooting at the same time. Grey shows surface detail and layer artifacts clearly, which matters when you're judging whether a percentage typed into Chitubox or Lychee actually preserved the model's finer features. It won't tell you anything about where a slicer's scale field lives, but it's the tool that tells you whether the number you entered was the right one.

Elegoo Standard Resin (Grey) on Amazon →

Uniform vs. per-axis scaling, in practice

Every slicer covered here defaults to uniform scaling — move the percentage on one axis and the other two follow, usually indicated by a lock or link icon next to the X/Y/Z fields. That default exists because non-uniform scaling distorts the model: a figure stretched 120% only in Z gets taller without getting proportionally wider, which reads as obviously wrong the moment you look at it. There are legitimate reasons to unlock the axes — stretching a display base without stretching the model on it, or nudging one axis to compensate for a printer's known dimensional error — but those are deliberate, narrow exceptions, not a general scaling method. The more common way people end up with a stretched model is accidental: the lock got toggled off at some point in the session and a later percentage change only hit one axis. Our guide to scaling STL files for 3D printing goes into more of the ways a scale change can go wrong beyond this one.

Where Cura, PrusaSlicer, and Bambu Studio put the control

The concept is identical across all three; the presentation isn't. Cura groups scaling with the model's move and rotate tools — selecting a model and opening its scale/transform control typically shows a percentage (or millimeter) field per axis, with a lock icon tying the axes together. PrusaSlicer surfaces the same information in an object manipulation panel that appears once a model is selected, listing size and scale side by side with its own uniform-scaling lock. Bambu Studio, despite sharing PrusaSlicer/Slic3r roots under the hood, actually handles this particular control more like Cura than like PrusaSlicer: scale is a toolbar icon rather than a standing side panel, and selecting it opens percentage and size fields for whichever model is selected. None of that changes what number you type in; it just changes how many clicks it takes to find the field.

Resin slicers add one more wrinkle: scale, then support

Chitubox and Lychee expose scale the same general way — select the model, adjust a percentage or absolute size in its manipulation panel, with uniform locking as the default. The practical difference with resin printing is workflow order: supports are generated relative to the model's current size and orientation, so resizing a model after supports are already placed usually means regenerating them, not just re-slicing. It's a good habit to settle on final scale first, then orient and support the model, then slice — doing it in the other order is a common way to end up with supports that no longer reach the surfaces they're supposed to hold up.

Frequently asked questions

Does 100% in my slicer always mean the model's real-world size?

No — 100% means the model's size as the STL file was authored, which may or may not match a real-world dimension or a named scale ratio. If you need the model at a specific scale (say 1:35) rather than just "however it was uploaded," you still need to know what scale it was originally modeled at before the percentage math means anything.

What percentage do I enter to go from 1:48 to 1:35?

Divide the scale ratio you have by the one you want: 48 ÷ 35 = 137.1%, entered as a uniform scale in whichever slicer you're using. The same division works for any ratio-to-ratio conversion — the "from" ratio on top, the "to" ratio on the bottom. That's a different calculation from scaling a full-size (1:1) model down to a single named scale, which uses 100 ÷ ratio instead — see the percent scale calculator's own FAQ for that case.

Can I scale just one axis to fix a dimension that's slightly off?

You can, but it's usually the wrong tool for the problem. Per-axis scaling distorts proportions, so it's better suited to deliberate cases like stretching a base than to correcting a model that came out slightly the wrong size — that's more often a units mismatch or an already-scaled import, which our guide to scaling STL files covers in more detail.

Do Chitubox and Lychee handle scale differently from Cura or PrusaSlicer?

The scale control itself works the same general way — percentage or size field, uniform lock by default — but resin slicers tie scaling to the support-generation step in a way FDM slicers don't. Rescale before you add supports, not after, or you'll likely need to regenerate them.

Why did my model print at a different size than the percentage I entered?

The usual culprits are the percentage getting applied on top of an already-scaled import rather than the original 100% size, or a units mismatch between how the model was authored (inches vs. millimeters) and what the slicer assumes. Measuring the printed result against your intended dimension with calipers is the fastest way to tell which one happened.

Sizing something for a build? Try the scale calculator or browse all recommended gear.