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Tolerance Stack-Up Calculator

Add components, set tolerances & directions β€” get gap/interference analysis for Worst Case and RSS instantly

1
Analysis Method & Units
Choose method
Both Methods WC + RSS side-by-side
Worst Case 100% interchangeable
RSS Method Statistical tolerance
2
Dimensional Loop Components
4 components
# Component Name Nominal (mm) +Tol (mm) βˆ’Tol (mm) Direction
Stack-Up Analysis Result
Worst Case + RSS Β· mm
LIVE
Nominal Gap
0.000
mm
WC Total Tol
Β±0.000
mm
RSS Total Tol
Β±0.000
mm
Status
β€”
Worst Case 100% Interchangeable
Min Gapβ€”
Max Gapβ€”
Total Toleranceβ€”
In-Spec?β€”
RSS (Statistical) 3Οƒ
Min Gapβ€”
Max Gapβ€”
Total Toleranceβ€”
In-Spec?β€”
β€”
Tolerance Contribution (% of WC Total)
Component Summary
# Name Nominal +Tol βˆ’Tol Dir Contribution (WC)
Worst Case: All tolerances at extreme simultaneously β€” guarantees 100% assemblability but conservative.
RSS Method: Statistical root-sum-square β€” realistic for production; assumes tolerances are independent and normally distributed.

Why I Built This Tolerance Stack-Up Calculator

Tolerance stack-up always looked straightforward on paper until I actually tried doing it for a real assembly. You start with four components, each with their own bilateral tolerances and loop directions, and suddenly you're in a spreadsheet trying to track worst case vs RSS while making sure you haven't mixed up a sign somewhere. One wrong cell and the whole thing is off.

The part that actually matters is which dimension is eating up most of your tolerance budget. That percent contribution calculation is what tells you where to tighten tolerances and where you're wasting money holding tight specs unnecessarily. Getting that out of a spreadsheet manually takes more work than the actual analysis.

I built this because I wanted something that handles the loop setup, does both Worst Case and RSS side by side, and immediately shows the contribution breakdown. No spreadsheet, no manual formula juggling.

Part of TaskJunction β€” free mechanical engineering calculators. No login, no signup, just tools that work.

β€” Vaibhav Dhokpande, Developer Β· TaskJunction