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-05Units: mm

Stack definition

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

Stack equation

Live signed nominal contribution by row.

35.00 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.

#LabelNominal (mm)Upper TolLower TolDirectionContributionDelete
1
+10.00
2
+20.00
3
+5.00

Monte Carlo

Distribution estimate

Ready
Normal sampling with σ ≈ tolerance / 3, clipped to each row tolerance bounds.

Mean

34.9991

Range

34.7266 to 35.2331

P05

34.8703

P95

35.1231

Histogram

2000 samples

34.7266
3
34.7688
9
34.8110
44
34.8532
128
34.8954
230
34.9376
365
34.9798
452
35.0221
375
35.0643
239
35.1065
116
35.1487
31
35.1909
8

Results

F-01 total nominal, F-02 worst-case, and F-03 RSS approximation.

Valid

Total nominal

35.0000

Worst-case min

34.6500

Worst-case max

35.3500

RSS tolerance

0.2291

RSS min

34.7709

RSS max

35.2291

RSS is shown as an approximation. Worst-case is deterministic and conservative.
Output is formatted for engineering review: nominal values are exact, worst-case is conservative, and RSS is a statistical estimate.

Formula reference

How the stack is calculated

F-01

Total nominal stack

Σ(direction_i × n_i)

Adds + rows, subtracts - rows.

F-02

Worst-case bounds

local_min = n_i - t_minus_i, local_max = n_i + t_plus_i

+ rows use local bounds directly.

F-03

RSS approximation

RSS_tol = sqrt(Σ(((t_plus_i + t_minus_i)/2)^2))

Approximation band, not worst-case.

Assumptions

Modeling notes

1D linear chain onlyRSS assumes independenceAsymmetric tolerances supportedMonte Carlo is an estimate

Validation cases

V-01 All positiveV-02 Mixed directionsV-03 Asymmetric tolerancesV-04 Zero toleranceV-05 Invalid input

Current stack expression

Live signed nominal terms

+10.00 + +20.00 + +5.00

Same signed nominal expression used by the calculator.