metricuno
How it worksIntegrationsPricingFAQ
Guides
A/B testing
Run tests that give answers you can trust: setup, statistics, duration and reading results.
Conversion rate optimization
Find where your store loses buyers and fix it, from research to rollout.
Experimentation
Turn one-off tests into a program: strategy, prioritization, velocity and governance.
Funnel analytics
Measure every step from landing to purchase, and see exactly where visitors drop off.
Page optimization
What works on home, category, product, cart and checkout pages.
Shopify optimization
Platform-specific CRO for Shopify stores: themes, apps, checkout and speed.
All guides →
Free tools
A/B Test Calculator
Plan how long to run a test, then check if the result is real.
Sample Size Calculator
How many visitors your A/B test needs, and how many weeks that takes.
Statistical Significance Calculator
Is your A/B test result real? p-value, lift and chance to win.
A/B Test Business Impact Calculator
The real revenue and ROI of your winning tests, after every correction and cost.
All free tools →
Log inStart free trial
Free · no signup · nothing leaves your browser

Free A/B testing tools

Plan a test, then find out if the result is real. Built on one tested statistics engine, so every tool gives the same answer for the same numbers.

The full calculator

A/B Test Calculator

Plan how long to run a test, then check if the result is real.

  • Test length from your traffic, or traffic needed for a fixed length
  • Frequentist and Bayesian results side by side
  • Sample ratio mismatch and stopping-too-early checks
  • Revenue impact, Slack summary and a shareable results image

Open the A/B test calculator →

Sample Size Calculator

How many visitors your A/B test needs, and how many weeks that takes.

  • Visitors per variant at any confidence and power
  • Weeks to run at your traffic
  • Multiple variants handled correctly

Open the sample size calculator →

Statistical Significance Calculator

Is your A/B test result real? p-value, lift and chance to win.

  • p-value and lift with confidence interval
  • Bayesian chance to beat control
  • Up to four variants, Holm-corrected

Open the significance calculator →

A/B Test Business Impact Calculator

The real revenue and ROI of your winning tests, after every correction and cost.

  • Wins compound across steps and overlap on the same page
  • Winner's curse and false discovery corrections
  • Fading effects, ship delay and a simulated range
  • Testing and build costs, ROI and payback month

Open the A/B test business impact calculator →

New to testing? Start with A/B testing: the complete guide, or read up on statistical significance and sample size.