MRR to ARR Calculator

Why MRR and ARR matter for subscription businesses

Monthly recurring revenue (MRR) and annual recurring revenue (ARR) are the two most widely-quoted metrics in SaaS and subscription businesses. They measure predictable revenue from active subscriptions, stripped of one-off fees, implementation costs, and professional services. ARR is simply MRR × 12 — a view of the same revenue on an annual basis rather than monthly. Which to report depends on audience. Board decks and investor updates usually quote ARR because the number is bigger and the year-on-year framing is cleaner. Internal operational dashboards usually quote MRR because monthly movements are easier to debug and faster to react to.

The four components of MRR movement

The headline number hides a lot of mechanics. Every month, MRR changes because of four distinct flows:

New MRR: revenue from customers who signed up this month. This is your acquisition engine — sales, marketing, product-led growth. A growing new-MRR line is the cleanest signal that demand is healthy.

Expansion MRR: revenue from existing customers who upgraded their plan, added seats, or moved to a higher tier. Expansion compounds — happy customers who grow within your product are often your most profitable source of new revenue.

Contraction MRR: revenue lost from existing customers who downgraded, removed seats, or moved to a cheaper tier. A recurring contraction line that does not reverse is often an early signal of product-fit erosion before it shows up as churn.

Churn MRR: revenue lost from customers who cancelled entirely. Churn is the most closely-watched number because it is the hardest to reverse — a cancelled customer usually does not come back without substantial effort.

Net new MRR = New + Expansion − Contraction − Churn. This is the bottom-line movement in any given month, and it determines whether ARR grew or shrank.

Gross MRR vs net MRR growth

Gross new MRR is the sum of New + Expansion — everything positive. Net new MRR is Gross minus Contraction and Churn. For fast-growing early-stage startups, gross and net can look similar because churn is small relative to new. For mature businesses, the gap between gross and net can be enormous — a business adding 500k gross new MRR but losing 400k to churn has only 100k of real growth, even though the sales and marketing teams are generating the same gross output.

The ARR conversion and why it sometimes overstates

ARR = MRR × 12 assumes every subscription renews at its current rate for a full year. That assumption is usually fine for healthy businesses with low monthly churn, because the annualised figure accurately represents the run-rate revenue if current state persists. But it overstates for businesses with high monthly churn — if 5% of MRR churns every month, simple MRR × 12 ignores that a meaningful chunk of that revenue will not actually land over the full year. Sophisticated SaaS companies report both: headline ARR as MRR × 12, plus a separate "churn-adjusted ARR" that projects expected revenue retention based on trailing cohort behaviour.

Patterns Commonly Observed in MRR

Three errors come up frequently in founder-built MRR dashboards. First, counting annual prepayments as MRR in the month they land — the revenue is real but it is not recurring monthly, so it inflates MRR and creates a fake drop the next month. Correct treatment: amortise annual payments over 12 months. Second, including one-off fees (setup, implementation, consulting) in MRR — these are legitimate revenue but not recurring, and mixing them dilutes the signal the metric is supposed to carry. Third, double-counting expansion when an upgrade mid-month is treated as both contraction of the old plan and new MRR on the new plan. Net the movement instead.

How investors read the numbers

When an investor asks for MRR growth, they typically want: gross new MRR last month, net new MRR last month, net new MRR trend over the last 6 months, and trailing twelve-month net revenue retention (NRR = 1 + (expansion − contraction − churn) / starting MRR). That combination shows whether growth is accelerating or decelerating, whether existing customers are a net source of revenue or a net drag, and whether the acquisition engine is gaining efficiency. A business with high gross and improving NRR is a compounding machine. A business with high gross but flat or declining NRR is running on a treadmill — adding revenue at the top while losing it at the bottom.