Engineering calculator
Tolerance Stack Analysis Calculator
Build a one-dimensional tolerance stack-up online, compare worst-case and RSS tolerance results, and document each feature in the same worksheet for review, print, or PDF export.
Tolerance stack workspace
The table starts with one editable line. Add more features as needed, choose the plus or minus contribution direction, and use the shaded summary columns as your running stack output.
Disclaimer: Use calculations at your own risk. For critical applications, verify results against your governing standards/specifications.
Tolerance Stack Analysis
Enter each feature's dimension and tolerance to build your stack, then reorder rows and add clear descriptions to keep the calculation and your record-keeping aligned.
| Line # | Description | Direction | Dimension (mm) | Tolerance (+/- mm) |
Accumulated Displacement (mm) |
Worst-Case Tolerance (mm) |
RSS Tolerance (mm) | Actions |
|---|---|---|---|---|---|---|---|---|
| Total | 0.00 | +/-0.00 | +/-0.00 | |||||
Graphic Representation
What this tolerance stack calculator helps you check
Use this tolerance stack calculator for one-dimensional engineering stack-ups where each feature adds to or subtracts from a final position, gap, clearance, fit, or overall dimension. It is useful for fixture stacks, machined parts, formed assemblies, shim studies, and tolerance analysis work where you want to compare nominal stack behavior with both worst-case and RSS assumptions.
The worksheet is designed for quick iteration: enter dimensions, assign a plus or minus direction, reorder rows as your stack-up changes, and keep plain-language descriptions alongside the math so the result is easier to review with manufacturing, design, supplier, or quality teams.
Common tolerance stack-up use cases
- Gap and clearance analysis between assembled parts.
- Fixture and datum-chain studies for machined or fabricated parts.
- Fit checks where several dimensions add and subtract through an assembly.
- Quick worst-case tolerance analysis before releasing drawings or revisions.
- RSS tolerance estimates when you want a more statistical stack-up view.
How to use the tolerance stack-up calculator
- Each row adds or subtracts one nominal dimension from the running stack based on the selected direction.
- Worst-case tolerance accumulates as the sum of absolute line tolerances.
- RSS tolerance accumulates as the square root of the running sum of squared line tolerances.
- The graphic view plots each feature from its running start point to its running end point so reversals are easy to see.
FAQ
What do the terms in the sheet mean?
Direction tells the stack whether that feature adds to the running result or subtracts from it. Dimension is the nominal size being added or subtracted. Tolerance is the allowed variation on that feature. Accumulated Displacement is the running nominal result after each row is applied.
What does the colored band behind tolerance mean?
It is a visual weight indicator. Larger tolerances produce a longer band so the biggest contributors stand out immediately.
What is the difference between worst-case tolerance and RSS tolerance?
Worst-case tolerance assumes every feature lands at its limit in the same direction at the same time, so it is the most conservative stack result. RSS tolerance, short for root-sum-square, assumes the tolerances vary statistically instead of all stacking at their extremes together, so it usually produces a smaller and more realistic combined variation for many manufacturing processes.
When should I use worst-case instead of RSS?
Use worst-case tolerance analysis when every limit must be guaranteed, such as tight fit, minimum clearance, or safety-critical assemblies. Use RSS tolerance analysis when feature variation is more independent and you want a realistic estimate of typical combined variation.