Tolerance Stack-Up Calculator
Add component nominal dimensions and signed lower and upper deviations to see the total range and RSS estimates.
Enter component dimensions and deviations.
Tolerance stack-up report
Nominal total:
Worst-case minimum:
Worst-case maximum:
RSS lower-side estimate:
RSS upper-side estimate:
A QUICK WALKTHROUGH
How to use this tool
- Choose one unit used by every dimension.
- Enter each nominal dimension with a lower deviation at or below zero and an upper deviation at or above zero.
- Review worst-case and RSS estimates, then copy or download the report.
Signed worst-case calculation
The minimum is the sum of nominal dimensions plus every lower deviation. The maximum is the sum of nominal dimensions plus every upper deviation.
RSS is an estimate
Each supplied lower and upper deviation is combined by root-sum-square on its own side. This assumes independent, centered variation. Limits are not standard deviations, so RSS is a planning estimate, not a guaranteed bound or confidence interval.
Local calculation
Inputs remain in this browser. The tool does not select fits, standards, datums, geometric tolerances, or engineering acceptance criteria.
GOOD TO KNOW
Common questions
Does it convert units?
No. Choose one unit and use it consistently for every nominal dimension and deviation.
Are deviations entered as magnitudes?
Enter signed offsets: lower deviations are zero or negative and upper deviations are zero or positive.
Is RSS a pass/fail result?
No. It is a statistical-style estimate under an independence and centered-variation assumption. Apply your own engineering method and acceptance limits.