Software-as-a-Service (SaaS) businesses are different from traditional companies. Instead of a one-time sale, they rely on subscriptions, which create predictable, recurring revenue. To measure the health and potential of this model, founders use a specific set of financial metrics. Think of them as the vital signs of your startup.

Mastering these core numbers helps you make smarter decisions, prove your business is healthy, and speak the same language as investors.

The heart of any SaaS business is its recurring revenue. This is tracked primarily through two key metrics: Monthly Recurring Revenue (MRR) and Annual Recurring Revenue (ARR).

MRR includes all recurring charges from subscriptions. It's the most direct way to measure your company's pulse. For example, if you have 50 customers each paying a $20 monthly subscription fee, your MRR is $1,000.

Calculating it is straightforward:

Annual Recurring Revenue (ARR) provides a longer-term view. It's simply your MRR projected over a full year.

Using our previous example, an MRR of $1,000 would translate to an ARR of $12,000. Investors often focus on ARR to gauge the company's scale and growth trajectory.

Revenue is only one part of the story. You also need to understand how profitable your service is and how much each customer is worth. This is where Gross Margin, Customer Acquisition Cost (CAC), and Customer Lifetime Value (LTV) come in.

A high gross margin means your business keeps a larger portion of each dollar of revenue, which can then be reinvested into growth. Healthy SaaS companies often have gross margins of 80% or higher.

To find your CAC, you divide your total sales and marketing spend over a period by the number of new customers you gained in that same period. If you spent $5,000 on marketing in a month and brought in 25 new customers, your CAC would be $200.

CAC is most useful when compared to Customer Lifetime Value (LTV), which is the total revenue you can expect to earn from a single customer over the entire duration of their subscription.

The ratio between LTV and CAC is critical. It tells you if your business model is sustainable. A healthy SaaS company should aim for an LTV that is at least three times its CAC. This 3:1 ratio indicates that for every dollar you spend acquiring a customer, you generate three dollars in return.

Acquiring customers is expensive, so keeping them is crucial. You also need to manage your cash carefully, especially in the early days when you might be spending more than you're making. This involves tracking Churn Rate, Burn Rate, and Cash Runway.

If you start a month with 200 customers and 10 of them cancel, your monthly churn rate is 5%. High churn can quickly sink a business, as it forces you to constantly replace lost customers just to stand still. Keeping churn low is a sign of a healthy, valuable product.

Finally, let's look at two of the most important metrics for survival: burn rate and runway.

If your company has $100,000 in revenue but $120,000 in expenses for the month, your net burn rate is $20,000. Knowing this number is critical for managing your finances.

Your Cash Runway is how many months your company can operate before it runs out of money, assuming your burn rate stays constant.

If you have $200,000 in the bank and a net burn of $20,000 per month, your runway is 10 months. Founders must monitor their runway closely to know when they need to raise more funding or cut costs.

Ready to test your knowledge? Let's see what you've learned about these core SaaS metrics.

By consistently tracking these metrics, you can understand your business's health, identify areas for improvement, and build a strong financial foundation for growth.