Tolerance loops
Define multiple independent 1D tolerance loops. Each loop has its own specification and contributor chain.
GD&T callouts
Add geometric dimensioning and tolerancing callouts. These are converted to equal bilateral tolerances and injected into the active loop.
Add GD&T feature
GD&T contributors in active loop
#Char.DescriptionTol zoneDatum ADatum BMMC±Equiv.
No GD&T callouts added yet. Use the form above.
GD&T to equal bilateral conversion
Position ⊕ Tolerance zone diameter t → equal bilateral ±t/2
Flatness / Profile ⌓ Bilateral zone t → equal bilateral ±t/2
Runout ↗ Full indicator movement t → equal bilateral ±t/2
Parallelism ∥ Zone t → equal bilateral ±t/2
MMC bonus tolerance is added to the base tolerance zone before conversion.
Flatness / Profile ⌓ Bilateral zone t → equal bilateral ±t/2
Runout ↗ Full indicator movement t → equal bilateral ±t/2
Parallelism ∥ Zone t → equal bilateral ±t/2
MMC bonus tolerance is added to the base tolerance zone before conversion.
Analysis results
Worst case and RSS stackup results across all active loops.
Sensitivity analysis
Drag sliders to explore the impact of tightening or loosening individual contributor tolerances on the RSS result.
Live results
Sensitivity ranking — RSS reduction if tolerance halved
Monte Carlo simulation
Simulate assembly gap distributions using random sampling across contributor tolerances.
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Yield (%)
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DPMO
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Simulated mean
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Simulated σ
Simulated gap distribution
Run the simulation above to see insights.
Tolerance converter
Convert unilateral or unequal bilateral tolerances to equal bilateral form for use in tolerance stackup analysis.
Input
Expression:
Converted equal bilateral
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Sigma / process capability reference
| Sigma (σ) | DPMO | Defect rate | Yield | Cp | Process description |
|---|---|---|---|---|---|
| 1σ | 691,462 | 69.15% | 30.85% | 0.33 | Very poor — no process control |
| 2σ | 308,538 | 30.85% | 69.15% | 0.67 | Poor |
| 3σ | 66,807 | 6.68% | 93.32% | 1.00 | Minimum acceptable (Cp = 1.0) |
| 4σ | 6,210 | 0.62% | 99.38% | 1.33 | Good — typical production target |
| 5σ | 233 | 0.023% | 99.977% | 1.67 | Very good |
| 6σ | 3.4 | 0.00034% | 99.99966% | 2.00 | World class |
Projects
Save, load, and manage your tolerance analysis projects. Projects are stored locally in your browser.
Saved projects
No saved projects yet. Create your analysis and save it above.
Export
Generate professional engineering reports and data exports from your current analysis.
CSV — all loops
Contributor data, results, and sigma reference. Opens in Excel or any spreadsheet app.
JSON project file
Full project data including all loops, GD&T callouts, and settings. Re-importable.
HTML report
Formatted engineering report with all results. Open in browser and print to PDF for distribution.
Report preview