Use the free tool below: your data never leaves your browser — all work happens on your device, and nothing is uploaded to any server.
What this tool does
Slicers give exact print times, but opening a slicer just to answer “roughly how long?” is slow, and sometimes the file is not to hand. This print time estimator gives a manual estimate from six numbers: model height, layer height, print speed, average path per layer, infill, and a travel and overhead allowance. It returns the layer count, the total path, and the estimated time in hours and minutes. Use it for planning a print day, for deciding whether a print fits before bedtime, or for comparing settings without re-slicing.
The tool runs in your browser and needs no account. It is an estimator, not a slicer, and it says so plainly: the slicer’s number always wins when you have it, because the slicer knows the real path, the retractions, and the acceleration limits of your machine.
The formula, in plain words
Print time is mostly distance divided by speed. The layer count is the model height divided by the layer height, rounded up: a 100 mm model at 0.2 mm layers needs 500 layers. If each layer averages 800 mm of extrusion path, the total path is 400,000 mm, or 400 metres. At 50 mm per second, that is 8,000 seconds, or about 2 hours 13 minutes, before overhead. The tool then adjusts the path for infill, because a denser interior means more path per layer, and adds the overhead percentage for travel moves, retractions, and heating pauses.
The two inputs people find hardest are the path per layer and the overhead. For the path, use your slicer’s preview on a similar model, or estimate it as the perimeter of a typical layer multiplied by roughly two for walls plus infill. For overhead, 20 percent is a reasonable default for a normal model, and 30 percent or more for a model with many small islands, where travel dominates. Both are guesses, and the tool is honest about that: change them and watch how much the answer moves.
A worked example
Take a 100 mm tall vase-mode-like model, 0.2 mm layers, 50 mm per second, 800 mm of path per layer, no infill adjustment, and no overhead. That is 500 layers and 8,000 seconds, 2 hours 13 minutes. Add 20 percent infill and the path grows to 960 mm per layer, giving 9,600 seconds, or 2 hours 40 minutes. Add 20 percent overhead on top and the estimate reaches 11,520 seconds, or 3 hours 12 minutes. One model, three answers, and the spread between them is the honest uncertainty of estimating without a slicer.
Now change the layer height instead. At 0.3 mm layers the same model needs only 334 layers, and the time falls by a third, to about 2 hours 8 minutes with the same infill and overhead. That is the real lever for speed: thicker layers cut time far more than a small speed increase, because speed increases hit acceleration limits on short paths, while fewer layers is a guaranteed saving. The estimator makes that trade-off visible in seconds.
Why real prints differ
Real printers do not move at the set speed all the time. They accelerate into moves and decelerate out of them, so short paths never reach full speed, and small detailed layers take far longer per millimetre than long straight walls. Retractions, Z hops, layer-change pauses, and cooling waits for tiny layers all add time that a distance-divided-by-speed formula cannot see. This is why a detailed miniature can take twice the estimated time while a big simple box lands close to it.
Temperature matters too. A hotend that cannot melt fast enough forces the printer to slow down, whatever speed you asked for, which is exactly what the companion volumetric flow calculator checks. If your prints consistently run long, check the flow limit before blaming the estimator: the printer may be protecting itself from underextrusion by going slower than the setting.
Using the estimate well
Use the estimator for decisions, not promises. It is good for answering whether a print is a two-hour job or an overnight job, whether thick layers save enough to matter, and whether a bigger model fits in the day you have. It is bad for promising a customer a delivery time or for scheduling a print farm to the minute. For those, slice the file: the slicer’s estimate, on a calibrated printer, is usually within a few percent.
A practical habit: estimate first, slice second, and note the difference. After a dozen prints you will learn your machine’s personal correction factor, for example that your printer runs about 25 percent over the simple estimate on detailed parts and about 10 percent over on simple ones. Apply that factor to future estimates and they become genuinely useful. This is an educational estimator, and your printer manual and filament maker’s guidance always govern temperatures, materials, and safety.
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