Tolerance Stack-Up Calculator

Inputs

Dimension count

Number of dimensions in the stack.

Dim 1 direction

Dim 1 nominal (D1)

Nominal size of the first stack dimension.

Dim 1 +/- tolerance (t1)

Bilateral plus/minus tolerance for dimension 1.

Dim 2 direction

Dim 2 nominal (D2)

Dim 2 +/- tolerance (t2)

Dim 3 direction

Dim 3 nominal (D3)

Dim 3 +/- tolerance (t3)

Default result

Nominal stack(S)

55mm

Pass

3 dimensions included in the stack.

Also computed

Worst-case tolerance(T_wc)0.23mm

Sum of all plus/minus tolerances.

Worst-case minimum(S_min)54.77mm

Worst-case maximum(S_max)55.23mm

RSS tolerance(T_rss)0.13748mm

sqrt(sum(t_i^2)); use only when statistical assumptions are justified.

RSS minimum(RSS_min)54.863mm

RSS maximum(RSS_max)55.137mm

Method notes 2 notes

Worst-case stack adds the absolute tolerance of every dimension, assuming all parts hit their least favorable limit at once.
RSS stack uses sqrt(sum(t_i^2)) and assumes independent, centered variation. It is not a replacement for process capability or datum/geometric tolerance analysis.