Check A/B test significance — conversion lifts that are real vs noise. Stop shipping coin flips — free, local, no signup.
Compute conversion rate from visitors and conversions with presets, history, and CSV export. Turn 2% into 3% deliberately — free, local, no signup.
Compute trial-to-paid conversion across visitor, signup, and paid stages with MRR math — find funnel leaks. Lift 15% trials to 25% deliberately — free, local, no signup.
Compute cost per mille for ad campaigns — compare display, video, and social CPMs. Judge a $12 CPM against returns — free, local, no signup.
Translate text to Braille Unicode patterns and back for accessibility work. Check ⠓⠑⠇⠇⠕ renders correctly — local conversion, free, no signup.
Check any color pair's WCAG contrast ratio with AA/AAA verdicts for normal and large text. Prove 4.5:1 before shipping — free, local, no signup.
The tool runs a two-proportion z-test (pooled standard error) and calls significance at p < 0.05 with a 95% CI on the difference — no power analysis. Needs adequate volume: 100 conversions per variant minimum, more for small lifts. Peeking early inflates false positives. Three presets: Winner, Flat, Loser.
Full business cycles (1–2 weeks minimum) covering weekday/weekend variance. Stopping at significance courts regression to the mean.
Overall winners can lose in key segments — check mobile, new users, and top geos separately before full rollout.
No — math runs locally in your browser. Data never leaves your device.
Last updated October 2026