Resin Exposure Time Calculator | PrintCalcLab

Estimate total print time for SLA/MSLA resin printers.

Resin printers spend far less of their time exposing than most people assume — the lift and retract cycle between layers often dominates the total print duration. This calculator reconstructs the same arithmetic your slicer performs: it counts layers from the model height, applies separate exposure times for bottom and normal layers, and adds the full lift, retract, and rest overhead for every single layer, giving you an honest total before you commit a vat of resin.

How It Works

The layer count is the model height divided by the layer height, rounded up. Bottom layers — clamped so they never exceed the total — use the longer bottom exposure time, and the remaining layers use the normal exposure. Each layer additionally pays a lift penalty of lift distance ÷ lift speed on the way up, the same again for retraction, plus any rest delay. As a worked example, a 50 mm model at 0.05 mm layers is 1,000 layers; with 2.5 s exposure, five 30 s bottom layers, a 5 mm lift at 2 mm/s, and 1 s rest, the lift overhead alone is 6 s per layer and the total lands around 8,640 seconds — roughly 2.4 hours.

FAQ

Why do bottom layers need longer exposure?

The first layers must bond firmly to the build plate and cure through the FEP film interface, so slicers expose them several times longer than normal layers. This calculator accounts for them separately and never lets the bottom-layer count exceed the total layer count.

Why does layer height change print time so much when exposure stays the same?

Halving the layer height doubles the layer count, and every layer carries the full lift, retract, and rest overhead in addition to its exposure. A 0.025 mm profile therefore takes nearly twice as long as 0.05 mm even with identical exposure settings.

Does model complexity or how full the plate is affect SLA print time?

Not in this model — unlike FDM, an MSLA printer cures an entire layer in one exposure regardless of how much of the build area it covers, so only height, layer thickness, exposure times, and lift motion determine the duration.

What is the rest time input?

Many printers pause briefly after retraction so the resin can settle and the FEP film can relax before the next exposure. That per-layer delay is added once per layer on top of the up-and-down travel time.