Toolyard

Tolerance Stack-Up Calculator

How to do a tolerance stack-up

  1. List each dimension in the chain on its own line, such as 25 ± 0.1, or 25 +0.1 -0.05 for unequal tolerances.
  2. Start a line with - for a dimension that is subtracted, such as a gap measured the other way.
  3. Compare the worst-case range with the RSS (statistical) tolerance.

Frequently asked questions

Worst case or RSS?

Worst case assumes every part is at its limit at once, which is safe but strict. RSS assumes the variations are independent and random, which is more realistic for many parts in a chain.

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