You can now work out how much traffic a frequentist experiment needs, and how long it will take to get there, inside LaunchDarkly. Start from the experiment list for a quick gut-check before you commit to a design, or from the builder to attach the estimate to that iteration, so the experiment carries its own sample size target and anyone reviewing it can see when it's ready for a decision. You can view, edit, or remove that target from the results page while the experiment runs.

Settling on a sample size up front is what holds your false positive rate to the significance level you chose, and until now it meant a spreadsheet or a separate trip to our website. Estimates assume steady traffic, so an experiment may hit its sample size earlier or later. Available for fixed-horizon frequentist experiments.

Read Sample size calculations (https://launchdarkly.com/docs/home/experimentation/sample-size-calculator) and Sample size calculations for frequentist experiments (https://launchdarkly.com/docs/guides/experimentation/sample-size-calc) to get started.