Free tools
Calculators for every subscription metric
Type your numbers in and read the answer. Each tool shows the formula it runs, what the result means, and where the definition is worth arguing about. Nothing you enter leaves the browser.
What are SaaS metric calculators?
SaaS metric calculators work out the standard subscription numbers — recurring revenue, churn, retention, unit economics and cash — from figures you already have, without a spreadsheet or an account. This set covers 12 of them. Every calculation runs in your browser as you type: no signup, no email wall, and no figure you enter is sent anywhere or stored. Each tool prints the formula it uses and links to the glossary entry behind it, because the arithmetic is rarely the part people disagree about — the definition is.
6 calculators
Revenue and retention
The size of the recurring base, normalised so mixed billing terms can be compared, and whether the revenue you won last month is still here this month.
MRR
Monthly Recurring Revenue is the monthly-normalised value of every active paid subscription: monthly plans at face value, quarterly plans divided by three, annual plans divided by twelve, less active discounts.MRR · ARR · Paying customers · Blended ARPUARR
Annual Recurring Revenue is Monthly Recurring Revenue multiplied by twelve — a run rate describing what the current subscription book would produce over a year if nothing changed.ARR · ARR in 12 months · Net new ARR added · Average net new MRR per monthARPU
Average Revenue Per User is Monthly Recurring Revenue divided by the number of active paying customers.ARPU · Annualised ARPU · New customer ASP · ASP minus ARPUChurn Rate
Customer churn rate is the number of customers who cancelled during a period divided by the number active at the start of that period, expressed as a percentage.Customer churn rate · Gross revenue churn · Net revenue churn · Annualised customer churn · Implied average lifetimeNet Revenue Retention
Net Revenue Retention measures what happened to the revenue of a fixed group of existing customers over a period: starting MRR plus expansion, less contraction and churn, divided by starting MRR.Net revenue retention · Gross revenue retention · Net revenue churn · Retained MRRSaaS Quick Ratio
The SaaS quick ratio divides the MRR you gained — new, expansion and reactivation — by the MRR you lost to contraction and churn.Quick ratio · MRR gained · MRR lost · Net new MRR
6 calculators
Efficiency and cash
What a customer is worth against what they cost to acquire, how long before they have paid that cost back, and how much time the balance leaves you to act on any of it.
LTV
Customer lifetime value is the gross margin a customer contributes before they churn — not the revenue they pay.Margin-adjusted LTV · Unadjusted revenue LTV · Implied customer lifetimeCAC
Customer acquisition cost is everything spent to win customers divided by the customers actually won.Blended CAC · Paid CAC · Total acquisition spendLTV:CAC Ratio
The LTV:CAC ratio divides margin-adjusted lifetime value by fully loaded acquisition cost to show how much contribution each acquisition dollar returns.LTV:CAC ratio · Net value per customer · CAC ceiling at 3:1CAC Payback Period
CAC payback period is the number of months a customer's gross margin must run before it repays what you spent acquiring them.CAC payback period · Monthly contribution per customer · Year-one net contributionBurn Rate
Burn rate is the cash a company consumes each month.Monthly net burn · Monthly gross burn · Implied runwayRunway
Runway is how many months of cash a company has left at its current net burn.Runway · Runway if burn stayed flat · Months lost to burn growth
The metric glossary
A calculator settles the arithmetic. The glossary covers the conventions, the edge cases and the choices that make two companies’ versions of the same number incomparable.
Frequently asked questions
Are these SaaS calculators free?
Yes — all twelve, with no signup, no email wall and no card. There is nothing to unlock and no limited version. Bastle itself is also free while in beta, so the calculators are not a sample of a paid product; they are a reference that happens to be interactive.
Do you store the numbers I type into the calculators?
No. Each calculator runs entirely in your browser: the formula is JavaScript that executes on the page as you type, and the values live in React state for as long as the tab is open. Nothing is sent to a server, nothing is written to storage or a cookie, and the inputs are not a form that submits anywhere. Close the tab and the numbers are gone. That means you can put real revenue figures in without treating it as a disclosure.
How accurate are these calculators?
The arithmetic runs at full floating-point precision and only the displayed figure is rounded, so the calculation is not where error enters. Accuracy is bounded by your inputs instead. Feeding in a customer count that includes trials, an MRR figure that counts annual contracts at their billed value, or a CAC that omits salaries will produce a precisely wrong answer. Every page writes the formula out and names the inputs it expects for exactly that reason.
Do these calculators match what Bastle computes internally?
They use the same formulas and the same default definitions the glossary documents, so a figure worked out here should reconcile with the product given identical inputs. The two are not doing the same job, though. A calculator takes aggregates you have already summarised; Bastle computes from subscription-level billing events, which is what lets it apply policy — delinquency window, trial handling, refund and coupon treatment, annual churn lookback — consistently across every customer and backfill history when you change one. Where the numbers diverge, it is almost always because the aggregate typed in here rests on a different definition than the one the workspace is set to.
Which calculator should I start with?
MRR, because most of the others take it as an input. Once you have a monthly-normalised revenue figure you trust, net revenue retention tells you whether the existing base grows on its own, churn tells you what is leaking, and runway tells you how long you have to act. LTV, CAC and payback are worth running after those, since they are only as sound as the churn and ARPU figures feeding them.
Can I get these metrics calculated from my own billing data?
Yes. Connect Stripe and Bastle backfills your billing history, then keeps every metric in the glossary current against the definitions you choose, segmentable and traceable back to the invoices behind each figure. It is free while in beta, with no card required.
Stop retyping the same numbers every month.
Connect Stripe and Bastle computes every metric on this page from your own billing history — backfilled, segmentable, and traceable to the invoices behind it. Free while in beta, no card required.