GD&T Pro

Tolerance Stack-Up Calculator

Build your chain of tolerance links, then compare all five calculation methods simultaneously.

Stack-Up Chain (0 links)
mm

No links yet — add your first tolerance contribution below.
Influence Factor:Use >1 for lever-arm or angular amplification effects (e.g., a tolerance acting through a 2:1 lever = factor 2.0). Use sin/cos values for angular contributions not aligned with the measurement axis. Default is 1.0 for direct linear contributions.

Add links to see results.

Worst Case: Adds all tolerances arithmetically. Use for safety-critical parts where every unit must assemble (100% yield).

RSS: Root-sum-of-squares. Statistically realistic — assumes independent, normally distributed variations. ≈99.73% coverage.

Modified RSS: RSS × 1.5 correction for real-world Cpk. Industry standard for most commercial assemblies.

Six Sigma: System sigma level determines coverage. 6σ = 3.4 defects per million; 3σ = 66,807 DPMO.

Monte Carlo: 10,000 random samples per link. Most realistic for non-linear assemblies, mixed distributions, and dependent variables.