The Six SaaS Numbers That Actually Matter

Why These Six and Not Fifty

Most SaaS metrics content throws forty acronyms at a founder who just wants to know if the business is okay. It isn't necessary. A five-to-fifty person software company can run on six numbers, tracked consistently, reviewed monthly.

The logic matters more than the formula. Each metric below answers a specific operating question: how big is the business, is it leaking, is it efficient at growing, and how long do you have left to figure it out.

ARR and MRR: How Big Is the Business, Really

Monthly Recurring Revenue (MRR) is the predictable revenue you'd expect to collect next month if nothing changed — subscription fees, not one-off services or setup charges. Annual Recurring Revenue (ARR) is just MRR times twelve, used for reporting and comparison, not because the business is billed annually.

The reason to separate recurring revenue from total revenue is discipline: one-time consulting fees or implementation charges can flatter a topline number while telling you nothing about the durability of the business. If a chunk of revenue disappears when a project ends, it isn't recurring, and it shouldn't be counted in MRR.

Gross Churn vs. Net Churn: Is the Bucket Leaking

Gross churn is the revenue you lost from cancellations and downgrades in a period, as a percentage of starting revenue. Net churn nets that loss against expansion revenue (upgrades, seat growth, add-ons) from existing customers in the same period.

Both numbers matter because they answer different questions. Gross churn tells you how well you're retaining what you sell — if it's high, something is wrong with onboarding, product fit, or the customers you're selling to in the first place. Net churn tells you whether growth from existing customers can outrun the leaks. A business with high gross churn masked by strong expansion is still fragile: expansion tends to dry up faster than a churn problem gets fixed.

Watch for a sneaky trap: net churn can look flattering while gross churn quietly gets worse. Track both, not just the net figure.

CAC, LTV, and Payback: Is Growth Worth What It Costs

Customer Acquisition Cost (CAC) is the fully loaded cost — sales and marketing spend, including salaries — to acquire one new paying customer over a given period. Lifetime Value (LTV) is a rough estimate of the total gross margin a customer will generate before they churn.

CAC Payback Period is the number of months of gross margin it takes to recoup what was spent to acquire a customer. This is usually the most useful of the three for a small business, because LTV requires assumptions about churn and lifespan far into the future that are shaky with limited data, while payback period is concrete and near-term.

As illustrative reasoning rather than a hard rule: a payback period under roughly 12 months is typically comfortable for smaller SaaS deals, because it means cash spent on growth comes back within a year and can be reinvested. A payback period stretching well past a year, especially alongside high churn, is usually a signal to slow spending and fix retention before pouring more into acquisition.

Runway: How Long Do You Actually Have

Runway is the number of months the business can keep operating at its current net burn rate (cash spent minus cash collected, per month) before the bank balance hits zero. It is the most important number in the room whenever the other five look shaky, because it defines how much time is available to fix them.

Runway should be recalculated every month, not estimated once and forgotten — burn rate shifts as headcount, revenue, and collections change, and a founder who is surprised by runway is a founder who ran out of options for a graceful fix.

Putting It on One Page

None of these numbers is useful in isolation reviewed once a quarter in a board deck. They're useful sitting next to each other, updated monthly, so a founder can see the whole shape of the business at a glance: how big it is, whether it's leaking, whether growth is efficient, and how much time is left.

Use the Finance Dashboard Template to pull these into a single monthly view, with plain-language definitions of what "healthy" and "needs attention" look like for each metric so the review doesn't require a finance background to run.