SaaS Metrics: The 10 Numbers a Small SaaS Should Track
The SaaS metrics a small subscription product needs fit on one screen: MRR, ARR, active subscriptions, ARPU, customer churn, revenue churn, new MRR, expansion and contraction MRR, trial conversion, and the traffic that feeds the trials. Everything else (CAC payback, LTV to CAC, magic number) becomes useful once you spend real money on acquisition.
This guide defines each of the ten, gives the formula, and says what a change in it usually means.
Which SaaS metrics matter for a small app?
| Metric | Formula | What it tells you |
|---|---|---|
| MRR | Sum of each paying subscription’s price normalized to a month | Your recurring revenue right now |
| ARR | MRR × 12 | The same number on a yearly scale |
| Active subscriptions | Count of paying subscriptions | How many customers pay you |
| ARPU | MRR / active subscriptions | What an average customer is worth per month |
| Customer churn | Churned customers / customers at start of period | How many people leave |
| Revenue churn | Churned MRR / MRR at start of period | How much money leaves |
| New MRR | MRR from subscriptions that started paying | How fast you add revenue |
| Expansion and contraction MRR | MRR change from staying customers | Whether customers grow or shrink |
| Trial conversion | Trials that started paying / trials that ended | Whether the product sells itself |
| Visitors to trials | New trials / unique visitors | Whether your site turns traffic into tries |
How do you calculate MRR and ARR?
MRR is the monthly value of every paying subscription. Take each recurring item, normalize it to one month (a yearly price divided by 12, a weekly price times 52 / 12), multiply by quantity, subtract discounts, and add everything up. Trials count as zero until they pay. Metered usage is usually left out because it is not predictable.
ARR is MRR times 12. It is the same number, scaled for comparisons and for talking to investors. It is not what you will collect in the next 12 months.
The edge cases (yearly plans, coupons, past due invoices) are where most spreadsheets go wrong. Our guide on how to calculate MRR from Stripe covers each one.
What are ARPU and active subscriptions?
Active subscriptions are the customers paying you today. In Stripe terms that is active plus past_due, since a failed card is not a cancellation yet.
ARPU (average revenue per user, sometimes ARPA per account) is MRR divided by active subscriptions. It is closely tied to churn: ChartMogul found median monthly customer churn of 6.1% for accounts paying under $25 a month and 2.2% above $500 (ChartMogul). Raising ARPU, through a higher tier or a yearly plan, often lowers churn as a side effect.
How should you measure churn?
Use two rates, both over the same 30-day window:
- Customer churn = churned customers / active customers at the start.
- Revenue churn = churned MRR / MRR at the start.
They answer different questions. If revenue churn is below customer churn, your cheapest customers are the ones leaving. The churn rate formula guide covers the counting rules, the churn rate calculator has worked examples, and SaaS churn rate benchmarks show what is normal at your price.
What are MRR movements?
MRR changes for four reasons, and seeing them apart tells you what to work on:
- New MRR: subscriptions that started paying, including trials that converted.
- Expansion MRR: staying customers who upgraded or added seats.
- Contraction MRR: staying customers who downgraded.
- Churned MRR: subscriptions that stopped paying.
Next month’s MRR = this month’s MRR + new + expansion − contraction − churned. If your numbers do not reconcile with that, something in your MRR model is off. Expansion also drives net revenue retention, explained in churn rate vs retention rate.
Why track trials separately?
A trial is not revenue and an expired trial is not churn. Track three trial numbers:
- Trials running now.
- Converted: trials that ended in the window and are now paying.
- Expired: trials that ended without a payment.
Low conversion with high traffic points at the product or onboarding. High conversion with few trials points at the top of the funnel.
Why include traffic in SaaS metrics?
Revenue metrics tell you what happened. Traffic tells you what is about to happen. Unique visitors, top sources and the pages people read before signing up are the leading indicators for next month’s new MRR. You do not need a heavy setup for that: cookieless tracking gives visitors, sources and pages without a consent banner, and free website analytics covers the options.
Which metrics can wait?
- CAC and CAC payback: useful once you pay for ads or sales. Before that, your acquisition cost is mostly your own time.
- LTV: usually computed as ARPU divided by churn. With small samples it swings wildly, so treat it as a rough guide.
- Cohort retention curves: worth building once you have a few hundred customers per cohort.
FAQ
How often should I check SaaS metrics?
MRR and active subscriptions weekly at most. Churn and trial conversion monthly, on a rolling 30-day window.
Should I convert currencies into one total?
Only if you also pick a fixed rate and date. Keeping each currency separate avoids exchange-rate noise looking like growth or churn.
Do I need a separate tool for SaaS metrics?
Not if your billing is in Stripe and something reads it correctly. A spreadsheet works until you have upgrades, discounts and yearly plans.
What is a good ARPU?
There is no universal good number. What matters is that ARPU pays for the time each customer costs you in support.
The revenue metrics above, per project
Indiehacker Studio connects to Stripe with a read-only restricted key and shows MRR, ARR, active subscriptions, ARPU, trials (running, converted, expired), customer churn, revenue churn and new, expansion and contraction MRR for the last 30 days. It works per project and sums every app you run in USD, converting other currencies at the day’s exchange rate. The same script adds cookieless analytics (visitors, sources, pages), a support chat and bug reports, so traffic, conversations and revenue sit on one dashboard. Visitors-to-trials is not computed for you yet; you read it from the two pages.
Revenue is part of Pro, $12 a month or $120 a year, with a 14-day free trial. See pricing or create a free account.