Bland Altman Agreement Calculator
Calculate paired measurement bias and descriptive 95% limits of agreement with a difference-versus-mean plot.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Pair observations by position and plot their within-pair mean against A-minus-B difference.
Difference=A−B; bias=mean(difference); limits=bias±1.96 sample SD(difference)
Worked example
The default differences 1,−1,1,−1,1 have bias 0.2 and sample SD √1.2; the descriptive limits are about −1.94707243 and 2.34707243.
Assumptions and input details
Independent pairs, consistent units and roughly normal differences for the conventional descriptive limits. These are not confidence intervals or predetermined acceptable limits; proportional bias, repeated measurements and clinical interchangeability are not assessed.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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