Gage R&R
Upload Part, Operator, Measurement data for an initial MSA screening calculation.
PDF Study Report IncludedOpen ToolProfessional Statistical Engineering Tools
Stat-Forge Tools and Calculators
Professional statistical engineering calculators for quality engineering, manufacturing, process improvement, coursework, and applied process analysis. Most tools support CSV upload, example data, and direct manual entry.
SPC, MSA & Quality Analytics Toolkit
From basic statistics to advanced process monitoring
The calculator collection is organized as a practical workflow: measurement-system analysis, distribution and homogeneity checks, process stability, process capability, and supporting statistical or engineering calculations. The advanced Stat-Forge material extends this path into PCA monitoring, Tensor SPC, Tensor Q residual monitoring, and structured-data diagnostics.
Use the statistical diagnostics on this page to evaluate data quality, distribution assumptions, variance consistency, and measurement system performance before applying process monitoring, capability studies, or decision-making methods.
Measurement System Analysis
Start by confirming that the measurement system can produce useful data before drawing conclusions about the process.
Basic EMP Study
Evaluate repeated part/operator measurements with probable error, ICC, and EMP monitor classification.
PDF Study Report IncludedOpen ToolShort EMP Study
Evaluate measurement-system discrimination with Short EMP metrics.
PDF Study Report IncludedOpen ToolProbable Error
Estimate measurement-system probable error and evaluate whether the measurement increment is appropriate.
PDF Study Report IncludedOpen ToolAttribute Agreement Analysis
Evaluate categorical or pass/fail inspection agreement across appraisers and known standards.
PDF Study Report IncludedOpen ToolDistribution, Normality & Homogeneity
Use these tools to understand whether the data are approximately normal, whether groups are similarly distributed, and which distribution best describes the process.
Normality Test Calculator
Evaluate Anderson-Darling, Shapiro-Wilk, and Skewness-Kurtosis normality diagnostics.
PDF Study Report IncludedOpen ToolAnderson-Darling Test
Focused Anderson-Darling normality test page with example data, charts, and downloads.
Open ToolShapiro-Wilk Test
Focused Shapiro-Wilk normality test page with Q-Q plot and downloadable results.
Open ToolHomogeneity Test
Evaluate group-to-group variance and mean consistency before comparing or combining data.
PDF Study Report IncludedOpen ToolANOVA & Tukey HSD
Compare group means with one-way ANOVA and Tukey HSD post-hoc pairwise comparisons.
PDF Study Report IncludedOpen ToolTwo-Way ANOVA
Evaluate two factor effects and their interaction using balanced two-way ANOVA with replication.
PDF Study Report IncludedOpen ToolDistribution Fitting
Fit Normal, Lognormal, Weibull, Gamma, Exponential, and Uniform distributions with AIC ranking and histogram overlays.
PDF Study Report IncludedOpen ToolProcess Stability
After the data and measurement system are understood, use control charts to determine whether the process is stable before calculating capability.
Consistency / I-MR Chart
Build an I-MR chart for sequential measurement data.
PDF Study Report IncludedOpen ToolXbar-R Chart
Upload subgrouped data and calculate Xbar-R center lines and control limits.
PDF Study Report IncludedOpen ToolXbar-S Chart
Upload subgrouped data and calculate Xbar-S center lines and control limits.
PDF Study Report IncludedOpen ToolControl Chart Rules
Screen control chart data for common run, trend, and out-of-control signals.
Open ToolAttribute Control Charts
Build p, np, c, and u charts for attribute quality data.
PDF Study Report IncludedOpen ToolProcess Capability
Use capability tools after the measurement system is acceptable, distribution assumptions are understood, and the process is stable.
Process Capability Study Report
Create a capability study report with control charts, histogram, probability plot, Cp/Cpk, Pp/Ppk, PPM, and sigma estimates for individual or subgrouped data.
PDF Study Report IncludedOpen ToolCp / Cpk
Upload process measurements and select the within-sigma method used for capability.
Open ToolPp / Ppk
Upload process measurements and calculate performance capability using overall sample SD.
Open ToolCp/Cpk Confidence Intervals
Estimate Cp and Cpk with approximate confidence intervals for capability-study planning and reporting.
Open ToolRegression Analysis
Model relationships between process inputs and responses using ordinary least squares regression, diagnostic evidence, and standardized Study Reports.
Simple Linear Regression
Fit one response to one predictor with fitted-line plot, ANOVA, coefficient table, residual diagnostics, and prediction evidence.
PDF Study Report IncludedOpen ToolMultiple Linear Regression
Fit one response using multiple predictors with adjusted R², VIF, coefficient diagnostics, residual plots, and observed-versus-fitted evidence.
PDF Study Report IncludedOpen ToolOrthogonal Regression
Compare two measurement methods when both X and Y contain measurement error, with method agreement diagnostics and engineering interpretation.
PDF Study Report IncludedOpen ToolPolynomial Regression
Model curved engineering relationships with quadratic or cubic fits, residual diagnostics, and decision-focused interpretation.
PDF Study Report IncludedOpen ToolStatistical Analysis & Planning
Use these tools for supporting calculations, planning, uncertainty, and general statistical analysis.
Standard Deviation
Upload data or paste values to calculate mean, variance, standard deviation, range, and CV.
Open ToolConfidence Interval
Upload data or enter summary statistics for a two-sided confidence interval for a mean.
Open ToolZ-Score
Calculate z-scores and normal probabilities from entered values or uploaded data.
Open ToolSample Size Calculator
Estimate sample size for means, proportions, and capability-study planning.
Open ToolQuality Metrics
Continuous Improvement & Quality Analysis
Prioritize improvement work and evaluate multi-step process performance using practical quality-engineering tools.
Pareto Analysis
Identify the vital few contributors with ranked counts, cumulative percentage, 80% threshold, and Pareto Study Report.
PDF Study Report IncludedOpen ToolRolled Throughput Yield
Calculate RTY across sequential process steps with step yield, cumulative yield, expected output, and RTY Study Report.
PDF Study Report IncludedOpen ToolEngineering Tools
Tolerance Stack-Up Calculator
Analyze assembly tolerance using worst-case, RSS, and Monte Carlo simulation methods with contribution and distribution charts.
PDF Study Report IncludedOpen ToolGD&T Tolerance Analysis
Calculate bonus tolerance, virtual condition, allowable position tolerance, and pass/fail status for size features.
Open ToolFit & Clearance Calculator
Calculate minimum clearance, maximum clearance, allowance, and fit type for mating feature limits.
Open ToolGeometric Tolerance Calculator
Evaluate true position, profile zone width, orientation error, and runout-style geometric conditions.
Open Tool