Reference
3D Printing Tolerance Chart
Typical dimensional tolerance and minimum wall thickness by process, from FDM and resin SLA to SLS, MJF, and DMLS metal, so you can spec a printable part.
3D printing tolerances vary widely by process. Resin (SLA) and metal (DMLS) are the most accurate; FDM is the loosest; powder-bed SLS and MJF sit in the middle. Most services quote a floor tolerance plus a percentage of the nominal dimension, so accuracy degrades on larger parts. This chart gives typical dimensional tolerance and minimum wall thickness by process. Treat every value as a starting point: it depends on the specific printer, material, part geometry, orientation, and the service you use.
Typical tolerance and minimum wall by process
Tolerances below are typical for a well-calibrated industrial machine. Many services state them as a floor for the first inch (about 25 mm) plus roughly 0.1% of the nominal dimension beyond that. Minimum wall is the thinnest reliable wall; thinner is sometimes possible on non-structural features.
| Process | Typical tolerance | Min wall thickness | Best for |
|---|---|---|---|
| FDM (filament) | +/- 0.2 to 0.5 mm (or +/- 0.5%) | ~1.0 to 1.2 mm | Cheap functional prototypes, jigs |
| SLA / DLP (resin) | +/- 0.1 to 0.2 mm | ~0.5 to 1.0 mm | Fine detail, smooth cosmetic parts |
| SLS (nylon powder) | +/- 0.3 mm (or +/- 0.3%) | ~0.7 to 1.0 mm | Durable functional nylon, no supports |
| MJF (nylon powder) | +/- 0.3 mm (or +/- 0.3%) | ~0.5 to 1.0 mm | Consistent end-use nylon at volume |
| DMLS / SLM (metal) | +/- 0.1 to 0.2 mm (plus ~0.1%) | ~0.4 to 1.0 mm | Metal prototypes and end-use parts |
Typical values only. Actual accuracy depends on printer, material, orientation, part size, and service. Metal (DMLS) parts are usually finish-machined on critical features to reach tighter tolerances.
Why tolerance varies so much between processes
SLA cures liquid resin with a fine laser or projector, so it resolves the smallest features and holds the tightest tolerance. DMLS fuses metal powder with a laser and is accurate, but heat and residual stress mean critical faces are typically machined afterward. FDM extrudes molten filament bead by bead, so layer lines and shrink make it the loosest. SLS and MJF fuse whole beds of nylon powder without support structures, trading a little accuracy for strong, isotropic functional parts. Because most of these quote a floor plus a percentage, a 20 mm part holds far tighter than a 200 mm one.
Design rules that protect tolerance
Orientation matters: the Z (build) axis is usually less accurate than X and Y, so place tight features in-plane. Add clearance to mating features rather than relying on nominal fit (roughly 0.1 to 0.2 mm for SLA, 0.2 to 0.4 mm for SLS and MJF, and 0.4 to 0.6 mm for FDM). Where a hole, thread, or mating face must be precise, print it undersize and ream, tap, or machine it, or move that part to CNC. Keep walls at or above the process minimum so features fully form and do not warp.
Values reflect common additive service specs and design guidance. Every number is process, printer, material, and service dependent; confirm the tolerance a service can hold on your geometry before release.
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Frequently Asked Questions
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