Expansion MRR Calculator

Expansion MRR is the extra monthly recurring revenue your existing customers generate when they upgrade plans, add more seats or buy add-on products, and it is one of the most valuable forms of growth a subscription business can have. This calculator brings the common sources of expansion together so you can see the full picture. You enter upgrade MRR from customers moving to higher tiers, seat MRR from teams adding more users, and add-on MRR from extra modules or products, then the tool totals them into your expansion MRR. It also expresses that total as a percentage of your starting base MRR, so you can judge how much extra revenue your current customers are contributing relative to the size of the book you already hold. Founders, customer success teams and revenue leaders watch expansion MRR closely because growth from existing accounts is usually far cheaper to win than new logos and tends to be stickier, which is why strong expansion underpins healthy net revenue retention. A few good practice tips help here. First, only include revenue from existing customers, since brand new accounts belong in new MRR. Second, measure expansion over the same period as your other MRR movements so everything reconciles. Third, watch which source drives the most expansion, because seat growth, tier upgrades and add-ons each point to different product and pricing opportunities. Tracking expansion MRR every month tells you whether your product is becoming more valuable to customers over time and whether your pricing captures that value. Used alongside contraction and churn, it gives you a clear, honest view of how your installed base is really performing.

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$8,000
Total expansion MRR
As % of base MRR4.0%

Expansion MRR = upgrade + seat + add-on. Percent = expansion / base x 100. Estimate only, not financial or tax advice.

How it works

The tool adds upgrade MRR, seat MRR and add-on MRR to give total expansion MRR. It then divides that total by your starting base MRR and multiplies by one hundred to show the percentage. All inputs are monthly figures from existing customers.

Worked example

With $4,000 upgrade, $2,500 seat and $1,500 add-on MRR, total expansion is $8,000. Against a base of $200,000, that is 8,000 divided by 200,000 times 100, which is 4.0 percent.

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Frequently asked questions

What is expansion MRR?

Expansion MRR is the additional monthly recurring revenue from existing customers who upgrade, add seats or buy add-ons. It excludes brand new customers, which count as new MRR. It is a key driver of net revenue retention.

Why show it as a percent of base?

Expressing expansion MRR as a percentage of your starting base MRR shows how much extra revenue your current customers add relative to the book you hold. It makes the figure comparable across periods of different size. A higher percentage signals strong account growth.

What counts as expansion?

Upgrades to higher plans, extra user seats and purchases of add-on modules all count, as long as they come from existing customers. Reactivated or brand new customers are tracked separately. Keep the categories consistent each period.