Statistical tools
Sample size & power calculator
Plan a study with confidence. Closed-form designs compute instantly in your browser; the flexible parametric survival explorer is powered by merlin.
Power curve
What a standard analysis hides · hazard ratio over time
Sample-size table
Assumptions, formula & reference
Methods text — for a protocol or grant
Reproduce this in R / Stata
See also: Survival DGM explorer· Multi-state explorer· how we pre-specify an analysis →
For study planning. These results assume the stated model holds; they are not a substitute for a statistician. Methods and references are shown under each result.