Elephant's foot in 3D printing: why the bottom flares and how to fix it

Elephant's foot is a 3D printing defect where the first few layers bulge outward, so the base of the part ends up wider than the walls above it. It comes from a first layer that is squished too hard or stays soft too long. Fix it by easing the Z-offset up, dropping the bed about 5 °C and turning on your slicer's elephant foot compensation.

What is elephant's foot in 3D printing?

Run a fingernail down the side of a box you printed. If it catches on a lip right at the bottom, that's it. The flare is usually a few tenths of a millimetre or less, which is invisible on a figurine and maddening on anything that has to fit.

You'll notice it most when a lid won't seat, a box rocks on its base, or a part won't slide into a slot. Holes on the bottom face come out undersized too, because the same squish pushes plastic inward into the hole. Bambu Lab's wiki calls this out for assemblies, snap fits, rails and shaft holes, where the flared base "directly affects fit."

The first layer is set up to flare. It's printed onto a hot bed, deliberately squished for adhesion, usually printed with the part-cooling fan off, and then it carries the weight and heat of every layer above it. A little spread is normal. Too much is a tuning problem.

What causes elephant's foot

There's rarely just one culprit. Most cases are a too-low nozzle plus a too-hot bed, with a heavy part making it worse.

How to fix elephant's foot, step by step

Work through these in order. The first two fix the cause; compensation and chamfers clean up whatever is left. Tick each one off as you go.

1. Ease the Z-offset up. Raise it 0.02–0.05 mm at a time (less squish) and print a first-layer test patch. You want lines that are flat and touching with no gaps, but still visible as lines. A first layer that looks like a sheet of glass is too low. Printers that measure Z-offset automatically by touching the bed with the nozzle (many 2025–2026 machines from Bambu Lab, Prusa, Elegoo and others) can still read it wrong if there's a blob on the nozzle: clean the tip, re-run calibration, then fine-tune with the printer's Z-offset or Live Adjust Z setting if it has one. Full method in bed leveling and Z-offset.
2. Drop the bed temperature 5 °C. PLA's glass transition is around 60 °C, so a 65–70 °C bed keeps the base soft for the whole print. Try 55–60 °C for PLA, 70–75 °C for PETG and 95–100 °C for ABS. Most slicers let you set a separate first-layer bed temperature, so you can keep layer one hot for grip and run the rest 5 °C cooler. Stay inside the filament's range or you'll trade a flared base for a print that pops off.
3. Turn on elephant foot compensation. This shrinks the outline of the first layer inward so that, after the squish, the base lands on size. Start at 0.1–0.2 mm; the slicer-by-slicer settings are in the table below.
4. Check first-layer flow and line width. If a profile pushes first-layer flow above 100% (Cura calls it Initial Layer Flow), set it back to 100%. A wider first-layer line, around 0.5 mm on a 0.4 mm nozzle, is normal and fine. If every wall looks fat, not just the base, you're over-extruding everywhere: see over-extrusion.
5. Chamfer the bottom edge in CAD. A 0.4–0.6 mm 45° chamfer gives the squish somewhere to go, so the flare fills the bevel instead of sticking out. This is the only fix that works even on a perfectly tuned printer.

Elephant foot compensation settings in each slicer

Every major slicer has this setting, but only three of them call it by the same name. All of them work the same way: they pull the first-layer outline inward by the distance you enter.

Two things confuse people the first time:

• The brim looks detached in the preview. That's expected. Compensation shrinks the first layer, and the preview doesn't simulate the squish that fills the gap. Prusa, Bambu Lab and OrcaSlicer all document this. If the brim really doesn't attach on the printed part, your value is too high.
• Thin features look pinched. PrusaSlicer (2.2 and newer) avoids shrinking thin features below two perimeter widths, so narrow bits can look odd in preview. They print fine. If one bothers you, set compensation to 0 for that model.

How to measure elephant's foot with calipers

For figurines, the default compensation is fine. For parts that must fit, measure once and set an exact value. You need digital calipers that read to 0.01 mm.

1. Print a test block. A 25 × 25 × 10 mm cube works. Set compensation to 0 (Cura: Initial Layer Horizontal Expansion 0) and turn the brim off.
2. Let the bed cool fully before removing it. Prying a warm part off can bend the base and skew the reading.
3. Measure the reference width. Take X and Y near the top, in the middle of each side. Avoid the corners, which bulge for other reasons.
4. Measure the base. Take X and Y right at the bottom edge with the jaws touching lightly. Squeezing flattens the flare and gives you a reading that's too small.
5. Work out the flare per side. Subtract the top width from the base width, then divide by 2 because the flare is on both sides. Average X and Y.
6. Enter it, reprint, re-measure. Adjust in 0.05 mm steps until the base and the top match within about 0.05 mm.

As a rule of thumb, here's what your number is telling you:

Design it out: chamfer the bottom edge

Even a well-tuned printer leaves a trace of squish. The permanent fix lives in the model: a small 45° chamfer, 0.4–0.6 mm, around the outside bottom edge. The flare fills the bevel and the part sits flush. Chamfer the bottom edge of any hole on the build-plate face too, so pins and bolts still go in. Our 3D printing design guide covers when to chamfer and when to fillet.

In OpenSCAD, the easy way is a hull() between a slightly inset sliver at the bottom and the full-size body:

// 40 x 30 x 20 mm block with a 0.5 mm 45-degree chamfer on the bottom edge
c = 0.5;
hull() {
  translate([c, c, 0]) cube([40 - 2*c, 30 - 2*c, 0.01]);
  translate([0, 0, c]) cube([40, 30, 20 - c]);
}

Or let the CAD Agent write it for you:

When it isn't elephant's foot

A few other defects show up at the bottom of a print and get misdiagnosed. Check which one you have before changing settings.

Frequently asked questions

Related articles

Tools for thisAll tools

Flow Rate CalculatorDial in the extrusion multiplier from a measured single-wall cube.

G-code ViewerInspect a sliced file layer by layer: paths, travels, speeds and filament use.

Watch it doneVideo library

0:31 Scale your 3d printing for an exact fit in your slicerSlicer Settings 0:32 Run these tests to fix any 3D printed surface isssueTips & Tricks 0:23 How to fix initial layer of a 3D print, with one settingTips & Tricks

Was this article helpful?

Yes Not really

Send

Thanks! We read every note and use them to decide what to update next.