Analytical Method Validation — ICH Q2

Accuracy (% Recovery) Calculator

Calculate percent recovery from spiked sample data across three concentration levels — the standard design for demonstrating accuracy per ICH Q2.

Why % Recovery Matters

Accuracy measures how close a test result is to the true (spiked or reference) value. For assay and impurity methods, ICH Q2 recommends demonstrating accuracy across a minimum of three concentration levels (typically 80%, 100%, and 120% of target), each with multiple replicate determinations.

% Recovery = (Measured Amount / Spiked Amount) × 100 Mean % Recovery (per level) = average of replicate % recovery values Overall Accuracy = mean % recovery across all levels combined

Typical Acceptance Ranges

Analyte Level	Common % Recovery Acceptance
Assay (major component, ~100%)	98% – 102%
Assay (broader, method-dependent)	95% – 105%
Impurities near reporting threshold	80% – 120%
Trace-level impurities	70% – 130% (method/level dependent)

Use your method's validated/compendial acceptance range — these are common industry benchmarks, not fixed requirements.

Interactive Calculator

Enter spiked and measured amounts for each replicate at three concentration levels (e.g., 80%, 100%, 120% of target).

Level 1 (e.g., 80% of target)

Level 2 (e.g., 100% of target)

Level 3 (e.g., 120% of target)

Acceptance Range (% Recovery)

Lower and upper bound, e.g., 98–102

Level	Mean % Recovery	Range

Overall Mean % Recovery

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This tool is for educational and preliminary assessment purposes. Final accuracy conclusions must follow your approved validation protocol's statistical methodology and pre-defined acceptance criteria, including the required number of replicates per ICH Q2 (typically 9 determinations across 3 levels, minimum).