Engineering calculator

Tolerance Stackup Analysis

Define a 1D stack, edit tolerances inline, and validate worst-case and RSS behavior against engineering reference cases.

F-01 / F-02 / F-03V-01 to V-05

Workspace toolbar

Show or hide Quick Start and advanced reference panels without affecting the main workflow below.

Stack definition

Edit rows inline. Calculation output will update from this state.

Stack equation

Live signed nominal contribution by row.

35.0000 mm

1+10.002+20.003+5.00

Contribution is the signed nominal term used in the equation. Tolerance propagation is shown separately in the results panel.

Reference presets

Load a known validation stack

V-01 to V-03

Load the documented validation cases before editing rows manually.

#	Label	Nominal (mm)	Upper Tol	Lower Tol	Direction	Contribution	Delete
1						+10.00
2						+20.00
3						+5.00

Input guide

Validation rules

Always active

Collapsed help covers labels, numeric input, direction, and zero-tolerance rows.

What-if preview

Scale tolerances globally or row-by-row without changing the base stack.

100% global

Scenario controls stay available for global scaling and row-level previews.

Monte Carlo

Sampled distribution

ReadyNo spec limits

Samples

Set optional lower and upper spec limits to estimate yield. Pass rate is the share of samples inside that band, not a deterministic acceptance proof.

Lower spec limit (mm)Upper spec limit (mm)

Monte Carlo uses a normal sample around each nominal, with sigma approximated as average tolerance / 3, then clips each draw to that row's tolerance bounds.

Mean (mm)

34.9991

Range (mm)

34.7266 to 35.2331

P05 (mm)

34.8703

P95 (mm)

35.1231

Yield

Set spec limits

In spec

Not configured

Histogram

2000 samples / mm

34.7266

34.7688

34.8110

34.8532

128

34.8954

230

34.9376

365

34.9798

452

35.0221

375

35.0643

239

35.1065

116

35.1487

35.1909

Results

Deterministic totals and RSS approximation.

Valid

Total nominal (mm)

35.0000

Worst-case min (mm)

34.6500

Worst-case max (mm)

35.3500

RSS tolerance (mm)

0.2291

RSS min (mm)

34.7709

RSS max (mm)

35.2291

Saved variants

Compare snapshots

0 saved

Variant AVariant B

Save at least two valid snapshots, then select Variant A and Variant B to compare nominal, worst-case, and RSS deltas.

Worst-case is deterministic and conservative. RSS is an estimate built from each row's average tolerance width and independent contributors.

Output is formatted for engineering review: nominal values are exact, worst-case is a stack boundary, and RSS is a statistical estimate rather than a pass/fail guarantee.

Spec Check

Go / No-Go

Unset

Spec limits are not configured.

Lower (mm)

Not set

Upper (mm)

Not set

Sensitivity

Dominant contributors

RSS share / mm

Spacer B+

76.2%0.2000

Bracket A+

19.0%0.1000

Shim C+

4.8%0.0500

Single-row dominance

Spacer B drives 76.2% of RSS contribution. Tightening this row should have the largest effect on stack variation.

Ranked by RSS contribution share. Rows with the largest share are the best candidates for tightening.