MRR & ARR Calculator
Free tool · by Daniel HaketThe heartbeat metric of any subscription business. Enter your paying customers and average price to get your MRR and ARR — plus where you'll be in 12 months at your current growth rate.
What this free tool is great for: a quick, one-off job with no signup — it runs entirely in your browser, so nothing leaves your device and there's nothing to manage.
Its honest limit: it works the number out once, by hand — it won't pull your live data, trend it over time, or flag when it shifts, so it's a snapshot rather than a dashboard.
MRR, ARR and why founders obsess over them
MRR is your predictable monthly recurring revenue — the subscription income you can count on next month. ARR is simply MRR × 12. Unlike a one-off sale, recurring revenue is an asset that keeps paying, which is why it's the number SaaS founders and investors watch above almost everything else: the closest thing a business has to a heartbeat.
Why growth compounds
The magic of recurring revenue is compounding. Steady monthly growth on a base that keeps paying snowballs — grow 8% a month and you're roughly 2.5x bigger in a year, without the base ever resetting to zero. That's the opposite of a project business, where every month you start again from nothing. Small, consistent MRR growth beats occasional big spikes precisely because it compounds.
Not all MRR is equal
The headline hides what's underneath. Break MRR into its moving parts: new (from new customers), expansion (upgrades from existing ones), contraction (downgrades) and churn (cancellations). Net new MRR is new plus expansion minus contraction and churn. A business adding lots of new MRR while quietly leaking churn can look healthy on the top line and be treading water underneath — which is why this simple calculator assumes no churn, and reality never does.
Retention is half the battle
You can't out-sell a leaky bucket forever. Once churn eats a big enough slice, every new sale just replaces a lost one and growth stalls no matter how hard the top of the funnel works. So track churn and net revenue retention alongside MRR: expansion revenue from happy customers is the cheapest MRR you'll ever add, and it compounds on a base you already own.
The four movements under one number
MRR is best understood as a balance of four flows: new MRR (first-time subscription revenue), expansion (existing customers upgrading or adding seats), contraction (downgrades), and churned MRR (cancellations). Two companies with identical headline growth can be in opposite health — one adding new customers into a leaky bucket, the other quietly expanding a loyal base. Reporting the four movements separately turns "MRR grew 6%" into an actual diagnosis: where did the growth come from, and what's working against it? Most SaaS dashboards worth their name show this waterfall, and it's the first view an experienced investor asks for.
Normalise everything monthly — and mind the annual-plan trap
The R in MRR means recurring, monthly, normalised. An annual plan of €1,200 contributes €100 to MRR — not €1,200 in its signup month, which would make growth look spectacular and January-heavy. The same discipline applies to quarterly plans, founding-member deals and discounted first months (count the price actually being paid now, not the list price). And one-off revenue — setup fees, consulting, lifetime deals — stays out entirely: it's real money but not recurring, and mixing it in poisons every trend line. The moment finance, founders and investors all compute MRR the same way, arguments about "which number is right" disappear.
Growth rate beats absolute MRR
€40k MRR means nothing without its derivative: is it growing 2% or 15% monthly? Compounding makes the difference brutal — 15% monthly is 5.3× in a year, 2% is 1.27×. For early-stage companies, the month-over-month percentage is the vital sign; as the base grows, sustaining percentages gets naturally harder and absolute additions become the fairer measure. Watch out for the small-base illusion in both directions: from €500 MRR, one customer is double-digit "growth"; percentage talk only becomes meaningful once the base can absorb single customer moves without spiking the chart.
MRR is not cash — and the gap can sink you
MRR is a smoothed, normalised abstraction; the bank account runs on actual cash timing. Annual prepayments put twelve months of cash in the bank against one month of MRR (great for runway, dangerous if you read it as monthly income); monthly billing means MRR and cash roughly track; failed payments create MRR that exists on the dashboard but never arrives. Involuntary churn from expired cards is the classic silent leak — dunning emails and card-updater services routinely recover several percent of revenue for near-zero effort. Track MRR for trajectory, cash for survival, and reconcile the two monthly so neither story fools you.
Committed MRR and the forecast you can defend
Plain MRR describes this month; decisions need next quarter. Two refinements help. Committed MRR (CMRR) adjusts today's number for what's already known: signed deals not yet live, and cancellations submitted but not yet effective — a truer base for planning than raw MRR that still counts a customer who gave notice. And a simple forecast — current MRR grown at your trailing three-month net growth rate — beats both optimism and paralysis; run it monthly and compare against what actually happened, and your projections calibrate themselves within a couple of quarters. Investors distinguish sharply between founders who quote raw MRR and those who can walk through committed MRR and its trajectory; the second conversation goes better.
From snapshot to system — where Databox does more
Calculating MRR by hand works until the second pricing tier, the first annual plan, and the customer who downgraded mid-month — then spreadsheet MRR quietly drifts from reality. That's where Databox does more: it pulls revenue data live from Stripe, your billing system and CRM, computes the MRR waterfall continuously, and puts the trend on a dashboard the whole team sees. The calculator on this page teaches the mechanics and answers quick what-ifs; a live dashboard makes the number un-fudgeable and always current — which is what turns MRR from a monthly ritual into an actual steering instrument. And when a board member or buyer eventually asks for your MRR waterfall, you'll export it in a click instead of reconstructing a year of spreadsheet edits under deadline. One last discipline: announce MRR internally the same day each month, from the same definition, in the same format — movements, waterfall, one sentence of interpretation. Ritualising the number keeps the whole team pointed at recurring revenue rather than vanity spikes, and after a few months the questions people ask in response become sharper than the report itself, which is exactly what a metric is supposed to cause.
Frequently asked questions
What is MRR?
Monthly recurring revenue — the predictable subscription income you earn each month. It's the core metric for any subscription or SaaS business.
What's the difference between MRR and ARR?
ARR (annual recurring revenue) is just MRR multiplied by 12. MRR is the monthly view; ARR the annual one.
Does this account for churn?
No — it's a simple projection assuming you keep customers. Real growth depends on retention too, so track churn alongside MRR in a tool like Databox.
More free growth & marketing metrics
Embed this tool on your site
Blogger, teacher or toolmaker? Put this calculator on your own page — free forever, no strings. Copy the snippet below (the credit link is appreciated and keeps the tool free):
This tool is free and runs entirely in your browser. The link above is an affiliate link: we may earn a commission if you sign up, at no extra cost to you, and it never changes our honest take.