OnSumoTools

MRR & Churn Forecaster (2026)

Project subscription revenue month by month, gross churn, expansion, and net-new bookings on one interactive curve.

100% client-side. Your inputs stay in this browser.

Stress-test monthly churn, expansion, and net-new bookings, see where MRR lands and how much growth churn silently taxes.

MRR at horizon

$109,907

ARR at horizon

$1,318,883

Annualized factor

69.4%

(1 − churn + expansion)12

ARR gap vs no-churn path

$1,061,366

(No-churn MRR minus modeled MRR) × 12 at the horizon.

At 4% gross churn, you leave about $1,061,366 of annual revenue on the table vs. the same expansion and net-new with zero gross churn (terminal-month comparison).

MRR trajectory

Carry-forward vs net-new MRR

Each month's ending MRR stacked into surviving revenue (after churn + expansion) vs fresh bookings.

How does the MRR Churn Forecaster work step by step?

The forecast starts with your current MRR and applies four forces each month: existing MRR carries forward reduced by gross churn, expansion revenue adds from upsells and seat growth, net-new MRR arrives from new customers, and the result becomes the next month's starting balance. The formula per month: End MRR = Start MRR x (1 - gross churn) x (1 + expansion rate) + new MRR. Annualized NRR = (1 - gross churn + expansion rate) ^ 12. An NRR above 100% means existing customers generate more revenue each year without any new sales. The growth ceiling is the first month where churned MRR equals new MRR, at which point net growth stalls. A zero-churn overlay line shows the exact revenue you lose to compounding churn over the forecast horizon.

What does a typical MRR Churn Forecaster result look like?

Current MRR $50,000. New MRR per month $5,000. Gross churn 4%. Expansion 1%. Month 1: start $50,000, churned $2,000, after expansion $48,480, plus new MRR = $53,480. Month 12: MRR reaches approximately $94,000. Month 24: approximately $150,000. NRR = 0.97^12 = 69%, meaning the existing base shrinks 31% per year in revenue terms. Toggling the zero-churn overlay shows $170,000 by month 24. The $20,000 gap is the compounding cost of 4% monthly churn.

Frequently asked questions

  • What is a healthy monthly churn rate for SaaS?

    For SMB SaaS products, 3 to 5% monthly gross churn is common. For mid-market and enterprise products with annual contracts, 0.5 to 1.5% is more typical. If your monthly churn exceeds 5%, the forecast will show a flattening curve because churn outpaces growth quickly.

  • What is the difference between gross churn and net churn?

    Gross churn counts only lost revenue from cancellations and downgrades. Net churn subtracts expansion revenue from that number. This tool uses gross churn and expansion as separate inputs so you can see each force independently. Net churn = gross churn minus expansion rate. Use this metric consistently over time to track improvement rather than optimizing for a single period's snapshot.

  • What does NRR above 100% mean?

    An NRR above 100% means your existing customers are spending more each year than they spent the year before, even without counting new customers. This happens when expansion revenue from upsells and seat growth exceeds churn losses. Top SaaS companies often target NRR of 110 to 130%.

  • Why does my forecast plateau?

    The curve flattens when the dollars churned each month equal the new MRR added. At that point, you need to either reduce churn, increase new MRR, or grow expansion revenue to resume upward growth. The tool marks this month with a growth ceiling annotation.

  • Does the cohort toggle change the calculation?

    Yes. The simplified default applies churn to the entire MRR base. The cohort toggle applies churn only to MRR that existed at the start of each month, not to net-new MRR added that same month. The cohort approach is slightly more accurate for businesses where new customers have a grace period before churn risk kicks in.

  • How should I set the expansion rate?

    Look at your last 3 to 6 months of expansion MRR from upsells, add-ons, and seat increases, then divide by starting MRR for those months. If your product has no upsell path, set this to 0%. Including expansion when it does not exist will inflate your forecast.

Related tools

Why a forecast beats a guess

Most founders know this month's MRR. Fewer can say what it looks like in a year if nothing changes. This forecaster projects MRR and ARR from 3 to 36 months using three levers: new bookings, expansion and churn.

Churn does the quiet damage. Lose 5 percent of revenue a month and you've lost nearly half your base within a year, even if sales keep running. The chart makes that visible before it happens.

Setting the three inputs

New bookings are the MRR you add each month from fresh customers. Be realistic. Use your trailing three-month average, not your best month.

Expansion is extra revenue from existing customers: upgrades, seats, add-ons. Enter it as a monthly rate. If you aren't sure, start at zero and see what the plan looks like without it.

Churn is the share of recurring revenue lost each month. Gross churn counts cancellations and downgrades only. Net churn subtracts expansion, and it can go negative when upgrades outrun cancellations.

Why the line flattens

If you add a fixed amount each month while losing a percentage of a growing base, the two forces meet. At that point MRR stops climbing. It's a plateau, and it's the math talking, not a bug.

The plateau sits at new bookings divided by the churn rate. Add 10,000 dollars a month with 5 percent churn and you level off near 200,000. Cut churn to 3 percent and the ceiling moves to about 333,000. That's a bigger win than doubling your sales, and it costs less.

NRR and the cohort view

Net revenue retention above 100 percent means existing customers grow faster than they leave. When that happens, the base expands by itself and the plateau disappears.

The cohort toggle is a display option. It splits the chart so you can see how each month's customers decay. It doesn't change the totals.

Using it in planning

Run three cases: cautious, expected and strong. Share the cautious one with anyone who controls your budget. Revisit monthly, since actuals drift from any model.

A forecast is only as good as its inputs. Treat the output as a range of outcomes, not a promise. Your figures stay in your browser.