ARR and MRR

How do you calculate ARR without fooling yourself?#

1. Write the eligibility policy before the formula#

Decide, in writing, whether each of these sits inside or outside recurring value:

2. Normalise, then annualise#

MRR = eligible contract value ÷ contracted months, then ARR = MRR × 12. Use the contract's own term as the denominator — a 24-month contract normalises over 24 months, not 12.

3. Build the movement bridge#

closing MRR = opening MRR + new + expansion − contraction − churn

Keep reactivations, foreign exchange, acquisitions and policy changes as separate visible lines when material. A total that moved for four reasons should be presented with four lines.

4. Reconcile to the accounting#

Show a short bridge from ARR to trailing recognised revenue that names the differences: term timing, services, non-subscription revenue, contract modifications, and the fact that ARR is an exit run rate rather than a period average.

5. Segment before anyone asks#

Report recurring value by product, customer size, geography, contract length and cohort. A growing total routinely hides a deteriorating segment — see Cohort Analysis.

6. Version the definition#

If the policy changes, restate prior periods or show the change as an explicit bridge item. A metric that improves because the policy changed is a governance event, not a growth event.

Worked example#

A SaaS company opens September with $150,000 MRR. During the month: new customers add $10,000, existing customers expand $7,000, contractions remove $2,000, churn removes $3,000.

closing MRR = $150,000 + $10,000 + $7,000 − $2,000 − $3,000
            = $162,000

closing ARR = $162,000 × 12 = $1,944,000

The services line. The company also signs $50,000 of one-time implementation work. That becomes GAAP revenue as the work is performed. It is excluded from ARR under the eligibility policy — and it would also be excluded under the SaaS Metrics Standards Board standard even if the customer bought implementation every single year.

The prepaid contract. One new customer pays $120,000 upfront for a 12-month subscription starting 1 September:

contract MRR = $120,000 ÷ 12 = $10,000
contract ARR = $10,000 × 12 = $120,000
cash collected in September = $120,000

Under a simple ratable-service assumption, roughly $10,000 of that becomes revenue each month and the remaining balance sits in deferred revenue. One contract, three different September numbers — $120,000 of cash, $120,000 of ARR, about $10,000 of revenue — and none of them is an error. The actual recognition pattern depends on the contract and the applicable standard.

The usage trap. A consumption customer has a $2,000 monthly committed minimum and used $8,000 of variable capacity last month.

Contracted MRR            = $2,000    → contracted ARR = $24,000
Total run rate last month = $10,000   → annualised     = $120,000

Reporting $120,000 as ARR claims five times the contractual visibility the company actually holds. The honest presentation is $24,000 contracted ARR + $96,000 annualised variable run rate, with the variable component shown on a trailing-three-month average so a single spike cannot drive the headline.

The caveat that matters: the × 12 is an assumption that this month repeats twelve times. For a contracted subscription that assumption is nearly free. For consumption revenue it is the risk, and the multiplication hides it.

What are the common mistakes?#

• Calling ARR revenue. It is a point-in-time operating run rate produced under a company policy. Say so in the same sentence you first use it.
• Annualising a peak usage month. Separate committed minimums from variable consumption and label each.
• Folding one-time services into the recurring base. Implementation, migration and custom work inflate scale and depress the gross margin that ARR implicitly promises.
• Publishing ending ARR without the bridge. The same $1.9M can be built from healthy new business or from one expansion masking broad churn.
• Changing the eligibility policy quietly. If expired-contract or delinquency treatment changes, the growth is definitional. Restate or disclose.

When does ARR break as a metric?#

When revenue is not contractual. Transactional marketplaces, seasonal consumption, advertising and episodic services have no recurring base to annualise. Trailing revenue, gross bookings, committed minimums or remaining performance obligations describe those businesses better.

When churn is monthly and real. A cancellable month-to-month plan sitting inside a metric named "annual" implies twelve months of visibility the contract does not grant. Pair it with churn rate.

When the renewal is unresolved. Two companies with identical expired contracts can report different ARR purely on grace-period policy. That is a comparability failure rather than an accuracy failure — and it is why benchmarking a peer's ARR growth without reading their definition is close to meaningless.

When the question is actually about economics. ARR is silent on margin, collection risk, concentration and support burden. A dollar of recurring revenue from a high-touch, low-margin customer is not equivalent to a dollar from a self-serve one. Pair it with gross margin, NRR and GRR and cash collection.