ARR vs MRR

If you run a subscription business, understanding the difference between ARR and MRR is foundational. These two metrics are the primary ways investors and operators measure revenue health in recurring revenue businesses. Yet I see founders confuse them constantly—which leads to misreported numbers, confused investors, and sometimes serious problems in fundraising.

MRR, or Monthly Recurring Revenue, is your baseline. It represents the predictable revenue you expect to collect each month from your subscription customers. Calculate it simply: take your total number of paying customers and multiply by the average revenue per user. If you have 100 customers paying $100/month, your MRR is $10,000.

ARR is simply MRR multiplied by 12. That's it. There's no complex calculation, no adjustment factors. The only reason to use ARR is that it sounds bigger and is easier for non-subscribers to grasp. A $1.2 million ARR sounds more impressive than $100,000 MRR—even though they're identical.

For internal management, MRR is superior. It gives you monthly granularity to spot trends, identify problems early, and measure the impact of changes. If you change your pricing on March 1st, MRR shows you the effect in March. ARR would take months to show the full impact. Use MRR for operations, reserve ARR for investor decks.

Breaking Down MRR Components

Understanding what drives MRR changes is crucial. Net New MRR has three components:

New MRR comes from brand new customers. This is your acquisition engine. If new MRR is growing, your sales and marketing are working.

Expansion MRR comes from existing customers who upgrade, add seats, or increase usage. This is the clearest signal of product stickiness and product-market fit. Strong expansion MRR means customers love your product enough to spend more. SaaS companies with negative churn actually grow MRR from existing customers even after accounting for churned revenue.

Churned MRR is revenue lost to cancellations or downgrades. This is the silent killer. Even 5% monthly churn compounds to 46% annual churn—meaning you'd lose nearly half your revenue in a year if you didn't add any new customers.

The best founders track each component separately. They know not just that MRR grew, but WHY it grew. This visibility is what enables strategic decisions about where to invest.