Net revenue retention calculator: How much MRR did your existing customers retain?

Version 1.0.0

Net revenue retention (NRR) tells you how the monthly recurring revenue (MRR) from customers active at the start of a month changed by its end. For one completed month, NRR is ending MRR from those same customers ÷ their opening MRR × 100.

Enter the opening amount and that group's expansion, reactivation, contraction, and churn. The calculator builds the ending amount and shows each movement behind the percentage. MRR from customers who first subscribed during the month stays out of both amounts.

Currency Required
Currency labels all amounts; it does not convert them.

MRR amounts

USD
From customers active when this month began.

Gains

For those same customers if they churned and returned.

Losses

Enter 0 if a movement did not occur. Exclude new customers.

How to use the calculator

  1. Choose a completed reporting month. From your billing records, find the MRR from customers with an active, billable subscription immediately before its first day.
  2. In one currency, enter that opening MRR and the month's four movements for those same customers. Use amounts already expressed as monthly recurring value. Enter 0 for a movement that did not occur; a blank means the amount is missing.
  3. Calculate NRR, then check the breakdown of gains and losses. Its first row shows the opening MRR, and its last row shows the ending MRR used for the percentage. If the form flags a combination, check the customer group and event categories in your source records.

Who belongs to the opening cohort?

The opening cohort contains customers with an active, billable subscription immediately before the chosen month's first day. Follow that same group through the end of the last day. A customer who first subscribes during the month is new business and does not enter this calculation. A former customer who was inactive when the month began is also outside the opening group, even if they return during the month.

Each reporting month has its own opening cohort. It differs from a signup cohort, which follows customers from the period when they first subscribed. ChartMogul's NRR report uses a period opening base and excludes new business; its cohort guide describes groups based on first subscription.

Use the same billing definition of active and the same currency throughout. Use monthly recurring amounts. If a plan bills yearly, use its monthly recurring value rather than the full annual charge. Leave out tax and one-time charges. These figures describe a recurring monthly run rate, not cash received or revenue recognized during the month.

How the movements make ending MRR

Expansion adds MRR when someone in the opening cohort pays more each month. Contraction is lost MRR when one of those customers pays less but stays subscribed. Churn is lost MRR when one cancels their final subscription. Count a loss as either contraction or churn, never both. ChartMogul's movement definitions make the same distinction.

This calculator includes reactivation only when someone in the opening group churns and returns within the same month. Enter the churned MRR and the later restored MRR separately. Do not also enter the restoration as expansion. A former customer who was still inactive when the month began is outside the opening cohort, so their return is excluded here. Reporting products use different reactivation rules: ChartMogul includes it in its NRR report by default, while Baremetrics omits it from its published NRR formula. Use the same rule when comparing months or reports.

April's opening group

Suppose the group starts with $10,000 in MRR. Its April movements are $1,200 in expansion, $300 in contraction, $500 in churn, and $100 in reactivation. The $500 churn includes the $100 restored when a customer returns later that month. Ending MRR is $10,000 + $1,200 + $100 - $300 - $500 = $10,500. NRR is $10,500 ÷ $10,000 × 100 = 105%.

The result table reconciles these amounts. Its row order shows the arithmetic, not the order in which customer events happened.

What the percentage tells you

At 100%, the opening group's ending MRR equals its starting MRR. Below 100%, its losses outweigh its gains. Above 100%, its gains outweigh its losses. A result above 100% can still include churn, as the April example does. NRR measures revenue from the starting customers, not the number of customers who stayed or your company's total MRR growth. Total growth also includes new customers.

Gross revenue retention (GRR) asks how much of the original MRR remained without using later gains to offset losses. This calculator does not report GRR. Its loss totals can include MRR that expanded earlier in the month. For example, a customer who starts at $100, expands to $150, then cancels creates $150 of churn, but only $100 was in opening MRR. Subtracting every loss from opening MRR could treat expanded revenue as original revenue lost. Customer-level billing events are needed to separate those amounts reliably.

When NRR is unavailable

If opening MRR and all four movements are 0, the calculator shows the $0 ending breakdown but marks NRR Unavailable. There is no opening amount to divide by, so this is not a 0% retention rate. If opening MRR is positive and ending MRR is zero, the valid result is 0%.

The calculator also rejects missing amounts, reactivation without a recorded churn movement, movements from a zero opening group, and losses that would make ending MRR negative. Check the original account records rather than changing a number just to obtain a result. The aggregate inputs cannot verify which accounts were active, when an event occurred, or how your billing system classified it. Compare later months only when the opening boundary, MRR definition, currency, and reactivation rule stay consistent.

To see how all-company MRR moved, including new customers, use the MRR waterfall calculator. For a wider monthly snapshot, use the SaaS metrics calculator, or browse SaaS tools for related calculators.