How to Calculate ARR: Formula, Steps & Common Mistakes

Most founders get ARR wrong because they treat every subscription the same way. Monthly plans, annual plans, and multi-year deals each need different handling. Here’s the correct ARR calculation, step by step.

Annual Recurring Revenue (ARR) is the total yearly value of all active recurring subscriptions, normalized to a 12-month period.

ARR = (Monthly subscriptions × 12) + Annual subscriptions + (Multi-year contracts ÷ number of years)

Notice the key part: annual subscriptions are not multiplied by 12. They’re already annual. This is the single most common ARR calculation mistake, and it doubles your number when you make it.

Step 1: Identify All Active Subscriptions

Pull every subscription that is currently active and recurring. Include:

Monthly plans (billed every month)
Annual plans (billed once per year)
Multi-year contracts (billed upfront or annually)

Exclude everything that isn’t recurring: one-time setup fees, implementation charges, usage overages billed after the fact, and refunds. If it won’t repeat on a predictable schedule, it doesn’t belong in ARR.

For the foundational definition, see What Does ARR Mean? Builder-Friendly Definition. For the full definition and context on why ARR matters, read the ARR meaning and definition. For a quick MRR-to-ARR conversion with input-cleaning rules, see ARR Formula: Convert MRR to ARR Without Counting Junk.

Step 2: Normalize to Annual Value

This is where the math matters. Each subscription type converts differently:

Monthly plans: Multiply MRR by 12.

20 customers × €49/mo = €980 MRR → €980 × 12 = €11,760 ARR

Annual plans: Use the contract value directly. Do not multiply by 12.

5 customers × €468/year = €2,340 ARR

Multi-year contracts: Divide the total contract value by the number of years.

1 customer × €5,000 over 2 years = €2,500 ARR

The Annual Plan Edge Case

This is the mistake that inflates ARR the most. If a customer pays €468/year for an annual plan, their ARR contribution is €468 — not €468 × 12 (€5,616).

The confusion happens because founders think in MRR terms. They see €468/year, divide by 12 to get €39/mo MRR, then multiply back by 12 to get ARR. The result is correct (€468), but the roundabout calculation introduces errors when annual plan pricing doesn’t divide cleanly by 12.

The rule is simple: if the billing cycle is already annual, the subscription value is already ARR. Don’t touch it.

If you offer a discount for annual billing (say €49/mo normally, €39/mo on annual), the ARR is the discounted annual total (€468), not the hypothetical monthly price annualized. You report what the customer actually pays, not what they would pay on a different plan.

Multi-Year Contract Handling

A 2-year contract worth €10,000 contributes €5,000 to ARR. A 3-year contract worth €15,000 contributes €5,000 to ARR. Spread the value evenly across the contract term.

This applies regardless of payment schedule. Whether the customer pays €10,000 upfront or €5,000 per year, the ARR contribution is the same: total contract value divided by total years.

Most bootstrapped SaaS founders won’t encounter multi-year deals often. If your business is mostly monthly and annual plans, Steps 1 and 2 cover 99% of your ARR calculation.

What to Exclude from ARR

One-time fees. Setup charges, migration fees, consulting hours — none of these recur, so none count toward ARR.

Usage-based overages. If you charge €49/mo base plus usage, only the €49 base is ARR. The overage is variable and unpredictable. Some companies track a “run-rate” that includes average overages, but that’s not ARR in the strict sense.

Churned subscriptions. If a customer cancelled yesterday, their subscription is no longer active. Remove it from your ARR immediately. Don’t wait until the billing period ends — ARR should reflect your current reality, not your billing schedule.

Free plans and trials. €0/mo × 12 = €0 ARR. They contribute nothing. Don’t count them, not even as “potential ARR.”

Worked Example

You run a SaaS product with mixed billing:

Type	Customers	Price	ARR Contribution
Monthly plan	20	€49/mo	20 × €49 × 12 = €11,760
Annual plan	5	€468/year	5 × €468 = €2,340
Multi-year (2yr)	1	€4,000 total	€4,000 ÷ 2 = €2,000

Total ARR = €11,760 + €2,340 + €2,000 = €16,100

If you’d mistakenly multiplied the annual plans by 12, your ARR would be €39,960 — more than double the real number. That’s the kind of error that wrecks your forecasts and misleads anyone looking at your metrics.

For all the edge cases beyond what’s covered here, see all ARR formula edge cases.

ARR vs MRR

ARR = MRR × 12 works only when all your subscriptions are monthly. The moment you add annual plans, that shortcut breaks.

The safe approach: calculate ARR from individual subscriptions as shown above. If you want to go the other direction — deriving MRR from ARR — divide each subscription’s annual value by 12. Just don’t multiply annual plan prices by 12 when going from MRR to ARR. Use the MRR to ARR converter to check your numbers.

FAQ

How do you calculate ARR?

Add up the annualized value of every active recurring subscription. Monthly subscriptions get multiplied by 12, annual subscriptions stay as-is, and multi-year contracts get divided by the number of years. Exclude one-time fees, usage overages, and churned accounts. The formula is ARR = (Monthly subs x 12) + Annual subs + (Multi-year contracts / years).

Is ARR just MRR times 12?

Only if 100% of your customers are on monthly billing. When you have annual or multi-year plans, MRR x 12 will overcount those subscriptions because they’re already at annual value. The correct approach is to normalize each subscription type individually and then sum them.

Should I include annual discounts in ARR?

Yes. ARR reflects what customers actually pay, not the list price. If a customer pays €468/year on a discounted annual plan instead of €588/year at the monthly rate, their ARR contribution is €468. Report real revenue, not hypothetical revenue.

What is the difference between ARR and revenue?

ARR counts only recurring subscription revenue, normalized to a 12-month basis. Total revenue includes one-time fees, overages, professional services, and other non-recurring income. ARR is a forward-looking metric that predicts your revenue run rate, while total revenue is a backward-looking accounting figure. For a deeper comparison, read about what ARR means in context.

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