The Essential SaaS Metrics Guide for Non-Finance Founders

I’ve been building software for SaaS companies for years, and I’ll let you in on something: most founders I’ve worked with don’t fully understand their own metrics. Not because they’re not smart (they absolutely are) but because nobody ever explained this stuff in plain terms.

So here’s my attempt at the SaaS metrics guide I wish someone had handed me years ago.

Why SaaS Metrics Are Different

If you’re coming from a traditional business background (or no business background at all), SaaS metrics can feel like learning a new language. That’s because they kind of are.

Traditional businesses think in terms of revenue and profit. SaaS businesses think in terms of recurring revenue and lifetime value. The subscription model changes everything about how you measure success.

The good news: once you understand the core concepts, everything else clicks into place.

The Metrics That Actually Matter

MRR (Monthly Recurring Revenue)

This is your heartbeat. MRR is the predictable revenue you can count on every month from active subscriptions.

How to calculate it:

MRR = Sum of all monthly subscription values

If you have annual plans, divide by 12 to normalize. A customer paying $1,200/year contributes $100 to your MRR.

The magic of MRR is predictability. Unlike one-time sales, you wake up on the first of the month already knowing most of your revenue. I find this genuinely calming, and I suspect investors do too.

ARR (Annual Recurring Revenue)

ARR is just MRR × 12. It’s the same information, annualized.

Why have both? Convention, mostly. Early-stage companies tend to talk MRR because the numbers feel more tangible. Once you’re doing $1M+ ARR, you switch to annual because “$83K MRR” sounds less impressive than “$1M ARR.”

Also, you’ll see both in investor conversations, so you need to be fluent in either.

Churn Rate

Churn is the percentage of customers (or revenue) you lose in a given period. It’s the silent killer of SaaS businesses.

Customer churn:

Customer Churn Rate = (Customers lost in period / Customers at start of period) × 100

Revenue churn (more useful):

Revenue Churn Rate = (MRR lost in period / MRR at start of period) × 100

Revenue churn is usually what you want to track because not all customers are equal. Losing a $500/month customer hurts more than losing a $50/month customer.

Here’s the thing about churn that took me a while to internalize: even “low” churn compounds brutally over time. 5% monthly churn means you’re replacing half your customer base every year. That’s a lot of treadmill running just to stay in place.

Net Revenue Retention (NRR)

This is my favorite metric because it tells you whether your existing customers are becoming more or less valuable over time.

NRR = (Starting MRR + Expansion - Contraction - Churn) / Starting MRR × 100

An NRR above 100% means your existing customers are spending more over time, even accounting for the ones who leave. The best SaaS companies have NRR of 120%+, meaning they’d still grow even if they stopped acquiring new customers entirely.

If your NRR is below 100%, you have a leaky bucket. New customer acquisition is just refilling what you’re losing.

CAC (Customer Acquisition Cost)

How much does it cost to acquire a new customer?

CAC = Total Sales & Marketing Spend / Number of New Customers Acquired

This sounds simple, but the denominator trips people up. Do you count only paid customers? What about trials that convert later? What’s your attribution model?

My advice: pick a reasonable methodology and be consistent. The trend matters more than the absolute number.

LTV (Lifetime Value)

How much revenue will a customer generate over their entire relationship with you?

Simple version:

LTV = Average Revenue Per Account / Monthly Churn Rate

If your average customer pays $100/month and your monthly churn is 5%, your LTV is $2,000.

The LTV:CAC Ratio

This is the metric that tells you whether your business model actually works.

LTV:CAC below 1:1. You’re losing money on every customer. This is fine for approximately zero months.
LTV:CAC of 3:1. Generally considered healthy for SaaS. You’re making $3 for every $1 spent acquiring customers.
LTV:CAC above 5:1. Either you’ve built something magical, or you’re underinvesting in growth.

Common Mistakes I’ve Seen

Obsessing Over Vanity Metrics

Total registered users, page views, social followers: these feel good but don’t pay the bills. I’ve seen founders spend hours polishing pitch decks full of impressive-looking numbers that completely obscured the fact that nobody was actually paying them money.

Ignoring Cohort Analysis

Your overall metrics blend together customers acquired at different times under different conditions. A founder once told me their churn was “about 4%.” When we dug into cohorts, it turned out recent cohorts were churning at 12% while the early customers (who they’d hand-held through onboarding) barely churned at all. Very different picture.

Calculating CAC Without Fully-Loaded Costs

Your marketing spend isn’t just ad dollars. It’s salaries, tools, agency fees, that conference sponsorship, the SDR team. If you’re not including everything, you’re lying to yourself about unit economics.

Getting Started

If you’re not tracking these metrics yet, start simple:

Get your MRR accurate first. Export your subscription data and make sure you can calculate this number reliably.
Add churn tracking. Know who’s leaving and when.
Build from there. Once you have clean MRR and churn data, most other metrics are derived calculations.

You don’t need fancy BI tools to start. A spreadsheet works fine. What matters is consistency and honesty about what the numbers actually say.

Profitual calculates these metrics automatically from your forecast, so you can see how changes to your assumptions affect your unit economics in real time. Try it free.