Calculators · 18 free
Free calculators for product managers
18 numbers a PM has to defend, worked out in code. No account, no sign-up, and no model anywhere near them — every figure here is arithmetic you can read, computed the moment you change an input.
Product metrics
7 calculatorsWhether the thing works, and for whom.
- A/B test sample sizeHow many people you need, and how long that will take.n = 2 (z₍α/2₎ + z₍β₎)² p(1−p) ÷ δ² per variant
- Funnel conversionWhere people leave, and which step is worth fixing first.Each step ÷ the step before it
- Activation and stickinessHow many who arrive actually start, and how often they come back.Activated ÷ signed up, and daily ÷ monthly actives
- Churn and lifetimeWhat a monthly churn rate means over a year, and how long a customer lasts.Lifetime = 1 ÷ monthly churn; annual retention = (1 − churn)¹²
- Experiment readoutWhether the test actually showed anything, or just moved.Two-proportion z-test, with a confidence interval on the difference
- NPSPromoters minus detractors, and what it rests on.(Promoters − detractors) ÷ everyone who answered
- Product-market fit scoreThe share who would be very disappointed without you.Very disappointed ÷ everyone who answered, against the 40% line
Project metrics
6 calculatorsWhether it will be done when you said.
- RICE scoreRank a candidate against the others competing for the same quarter.Reach × Impact × Confidence ÷ Effort
- ICE scoreRICE without reach: three judgements, for a list too long to research each item.Impact × Confidence × Ease
- Sprint capacityWhat the team can actually take on, before anyone commits.People × days × focus, converted at your velocity
- WSJFWhat to do next when everything is urgent.Cost of delay ÷ job size
- Cycle time and work in progressHow long a ticket takes, given how much is open at once.Little's Law: cycle time = work in progress ÷ throughput
- Backlog forecastWhen the work runs out, as a range rather than a date.Items ÷ velocity, widened by how much velocity swings
Business metrics
5 calculatorsWhether it makes money, and for how long.
- RunwayHow long the money lasts, and what changes that.Cash ÷ (burn − revenue), month by month with growth
- Market sizingTAM, SAM and SOM, from numbers you can defend.Accounts × price, narrowed twice
- LTV and paybackWhat a customer is worth, what they cost, and when they pay you back.LTV = margin per month × lifetime; payback = CAC ÷ margin per month
- MRR movementWhere revenue actually went this month, and whether growth is hiding a leak.Start + new + expansion − contraction − churn
- Break-evenHow many you have to sell before the month stops costing money.Fixed costs ÷ (price − cost to serve)
Why these are free
A calculator is a formula, and a formula is not worth charging for. What PikoPM sells is the job around it: scoring a whole backlog from a Jira board rather than one item at a time, planning a real team with holidays in three countries, writing the document that carries the number to the people who have to agree with it.
So these run for anyone, with no account and no limit. Where a calculator has a tool behind it that does the whole job, the page says so at the foot — after the answer, not instead of it.