Uncertia: Measurement Budget

Uncertia builds measurement uncertainty budgets the way the GUM (JCGM 100:2008) describes them, on your iPhone or iPad, with every step visible. It is made for calibration technicians, metrologists, quality engineers, laboratories working to ISO/IEC 17025, and students learning uncertainty evaluation. BUILD THE BUDGET - Keep any number of budgets in a local library; duplicate one to start the next - Type A rows from raw readings: paste or type them and get the mean, experimental standard deviation s, s/√n, and ν = n − 1 - Type B rows from certificates and specifications: normal (k = 2 or the certificate's k), rectangular, triangular, U-shaped, or a standard uncertainty you already have - Sensitivity coefficients, input estimates, units, and evidence notes for every row - Degrees of freedom per row, typed directly or estimated from how reliable a bound is - Correlation coefficients between rows, with a check that the set is consistent SEE THE RESULT - Combined standard uncertainty, including correlation terms - Welch–Satterthwaite effective degrees of freedom - Coverage factor from the Student t distribution at 68.27, 90, 95, 95.45, 99, or 99.73 %, or a fixed k - Expanded uncertainty reported with two significant digits and the result rounded to match - Contribution chart showing which source dominates the variance CHECK IT - Monte Carlo propagation of the input distributions (JCGM 101) with up to one million trials, a histogram, and a comparison of the coverage interval with y ± U - Conformity decisions against tolerance limits with simple acceptance or a guard band of U (ILAC-G8), probability of conformity, and test uncertainty ratio REPORT IT - PDF report with the statement, budget table, evidence, coverage reasoning, Monte Carlo check, conformity decision, and your notes - CSV table for spreadsheets and quality systems - Backup and restore files for the whole library LEARN IT - A written method guide covering Type A and Type B evaluation, distributions, sensitivity coefficients, correlation, effective degrees of freedom, coverage factors, Monte Carlo, decision rules, and references - Worked examples that reproduce published results: EA-4/02 S2 (10 kg weight, U = 59 mg) and GUM Annex H.1 (gauge block, νeff = 16, k = 2.92) PRIVATE BY DESIGN Everything is calculated and stored on the device. No account, no subscription, no ads, no analytics, no tracking. Uncertia supports transparent GUM-style calculations and review. Confirm the measurement model, correlations, distributions, sensitivity coefficients, degrees of freedom, traceability, decision rules, and reporting requirements with your laboratory procedure.