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Measurement System Analysis (Gage R&R) Calculator

Evaluate measurement system quality with Gage R&R analysis. Calculate repeatability, reproducibility, GRR percentage, number of distinct categories, and determine system acceptability.

Inputs

Results

GRR % of Total Variation

33.92%

Assessment

Unacceptable — needs improvement

Repeatability (EV)0.15
Reproducibility (AV)0.1
GRR (Gage R&R)0.18
Total Variation0.53
Distinct Categories (ndc)3
EV % of Total28.22%
AV % of Total18.81%
PV % of Total94.07%
Study Variation (5.15σ)0.93
How to Use This Calculator
  1. Enter Number of Parts, Number of Operators, and Number of Trials.
  2. Set Part Variation (PV), Operator Variation (AV), and Equipment Variation (EV).
  3. Review GRR % of Total Variation and Assessment.
  4. Use Repeatability (EV) and Reproducibility (AV) to inform your decision.
  5. Use the chart to visualize the results and explore different scenarios by adjusting inputs.

What each input means

Number of Parts
Number of distinct parts measured in the study. Standard is 10 parts.
Number of Operators
Number of different operators (appraisers) who measured the parts.
Number of Trials
Number of times each operator measured each part. Typically 2-3 trials.
Part Variation (PV)
The variation between parts — the actual process spread. Larger PV relative to GRR is better.
Operator Variation (AV)
Reproducibility — variation caused by different operators measuring the same part.
Equipment Variation (EV)
Repeatability — variation when the same operator measures the same part multiple times.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Number of Parts = 10, Number of Operators = 3, Number of Trials = 3, Part Variation (PV) = 0.5 = 6 input(s) provided
  2. Calculate GRR % of Total Variation
    GRR % of Total Variation
    33.92 = 33.92
  3. Calculate Assessment
    Unacceptable — needs improvement = Unacceptable — needs improvement
  4. Calculate Repeatability
    Repeatability
    0.15 = 0.15
  5. Calculate Reproducibility
    Reproducibility
    0.1 = 0.1

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