Skip to content
Log in

Free tools

Calculators for experiments, prioritisation, retention and market sizing. Free, no account, and everything is calculated in your browser.

Plan an experiment

  • A/B test sample size calculator

    How many participants each variant needs to detect the effect you care about, and how long recruiting them takes.

  • Minimum detectable effect calculator

    The smallest conversion increase your traffic and test duration can detect reliably, as a relative uplift and in percentage points.

Read test results

  • A/B test results calculator

    Compare two variants of a finished test: the difference in percentage points, its confidence interval and the p-value.

  • Statistical significance calculator

    Is the gap between two groups real or noise? A p-value with a one- or two-sided test, explained with a picture.

  • A/B/n test results calculator

    Compare three to six variants of a finished test: every pair, with a correction for multiple comparisons.

  • Confidence interval calculator

    How precise a conversion rate is, and how many visitors you need for a tighter range.

Prioritise

  • RICE score calculator

    Score and rank ideas by reach, impact, confidence and effort, then export the list as CSV.

  • ICE score calculator

    A quicker way to rank ideas: impact, confidence and ease on a 1 to 10 scale.

Understand users and market

  • Cohort retention calculator

    Paste a cohort table and see the heatmap, the average retention curve and where it flattens.

  • TAM, SAM and SOM worksheet

    Size your market bottom-up, with every assumption visible and a low, base and high range.

  • NPS calculator

    Your Net Promoter Score from counts or raw 0–10 answers, with its margin of error and the answers you need.

  • Survey sample size calculator

    How many answers a survey needs for your margin of error, how many people to invite, and how precise the answers you have are.

Revenue and unit economics

  • LTV calculator and LTV:CAC ratio

    What a customer is worth in gross profit, from ARPA, margin and churn, and whether it covers the cost of winning them.

  • CAC calculator

    Customer acquisition cost from ad spend, other sales and marketing costs and new customers, with LTV:CAC and payback.

  • CAC payback period calculator

    How many months until a new customer pays back its acquisition cost, with and without churn.

  • Churn rate and NRR calculator

    Customer churn, revenue churn, GRR and NRR from one period's numbers, with monthly and annual figures.

Work with engineers