Measurement Uncertainty Budget Builder

Quadrature combination assumes the five components are independent. They frequently are not — an operator who conditions specimens badly contributes to both the operator and conditioning terms, and double-counting inflates the budget while a shared systematic error escapes it entirely. Each input must already be a standard uncertainty: a rectangular tolerance of ±a contributes a/√3, a triangular one a/√6, and entering the half-width directly overstates it by around 70%. The confidence level shown assumes a normal distribution and a large effective degrees of freedom; with few repeats, use a Student-t coverage factor from the Welch-Satterthwaite equation instead of k = 2. Uncertainty is not tolerance — a result inside specification but with an interval straddling the limit has not demonstrated conformity, which is what ISO 14253-1 decision rules exist to settle.