Engineering lab · Interactive tool

Linear Tolerance Stack Calculator

Model signed nominal contributors with separate bilateral limits. Compare deterministic worst-case accumulation with an RSS estimate, then export the working stack.

Signed linear tolerance contributors
Contributor	Direction	Nominal (mm)	+ Tol.	− Tol.
Contributor 1 label	Direction for Housing shoulder	nominal for Housing shoulder	plus for Housing shoulder	minus for Housing shoulder
Contributor 2 label	Direction for Spacer	nominal for Spacer	plus for Spacer	minus for Spacer
Contributor 3 label	Direction for Bearing width	nominal for Bearing width	plus for Bearing width	minus for Bearing width
Contributor 4 label	Direction for End plate	nominal for End plate	plus for End plate	minus for End plate

+Housing shoulder

+Spacer

−Bearing width

−End plate

Nominal result0.200 mmΣ signed nominal dimensions

Worst-case limits0.060 to 0.340 mm−0.140 / +0.140

RSS estimate0.12652 to 0.27348 mmAssumed center 0.200 ± 0.07348 mm

Revision 1.3 · Reviewed 24 September 2026 · Jared Maffucci

Model, assumptions, and a reproducible reference case

μ = Σ sᵢ[nᵢ + (tᵢ⁺ − tᵢ⁻)/2]; T_RSS = √Σ[(tᵢ⁺ + tᵢ⁻)/2]²

Reference inputs

A = 10 ± 0.1 mm; B = 4 +0.2/−0.3 mm; stack A − B.

Expected assumed rss center: 6.05000 mm
Calculated by this tool: 6.05000 mm

Worst-case limits: 5.7–6.4 mm. RSS half-width: 0.26926 mm about the assumed center. Independent processes, midpoint centering, and equal sigma coverage are assumed.

Check the material basis, load cases, and applicable design criteria before using a result. Warning thresholds are prompts for review, not acceptance criteria.

How to read the result

Worst-case arithmetic places every contributor at the limit that drives the result in the same adverse direction. That is conservative and distribution-free.

RSS combines the half-widths of independent contributor intervals and places the result around the sum of their signed midpoints. Asymmetric tolerances therefore shift the assumed center away from the nominal stack. The estimate requires processes centered at those midpoints and equal sigma coverage for all half-widths; it is not a process-capability claim. See Scholz’s review of tolerance-stack methods for assumptions and mean-shift limitations.

Before releasing a stack

Confirm each sign from a closed dimension loop
Trace every contributor to a controlled feature or interface
Separate measurement uncertainty from product variation
Check assembly shift, temperature, wear, and deformation
Tie the resulting clearance or interference to a functional requirement

Direct conversation

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