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SaaS growth calculator

Project customers and MRR from your sign-ups, activation and churn. Move the sliders to see what happens, pin a baseline to compare a what-if, and find the lever that moves growth most.

Your sign-ups, activation and churn

%

0% keeps sign-ups flat. Growing marketing or SEO fits here; viral growth works differently. How to model it

%

Share of sign-ups who become paying customers.

%

Share of customers lost each month.

$/ month
Currency
Project over
Customers in 24 months
1,637
718% vs today
MRR then
$80.2K
ARR $962.3K
Customers lost along the way
963
64 in the last month
Where it levels off
2,500
Customers, if nothing changes.
Show
Month 24Customers1,637
05001K1.5K2K03691215182124

What moves the needle: customers in 24 months if one lever gets 10% better

  • 10% more sign-ups+156
  • 10% better activation+156
  • 10% less churn+72

More sign-ups and better activation add the same, since both bring in the same new customers. Less churn pays off slowly but compounds: the longer the horizon, the more it is worth.

Month-by-month table
MonthGainedLostCustomersMRR
Today200$9,800
11008292$14,308
210012380$18,636
310015465$22,790
410019547$26,779
510022625$30,607
610025700$34,283
710028772$37,812
810031841$41,199
910034907$44,451
1010036971$47,573
11100391,032$50,570
12100411,091$53,448
13100441,147$56,210
14100461,201$58,861
15100481,253$61,407
16100501,303$63,851
17100521,351$66,197
18100541,397$68,449
19100561,441$70,611
20100581,483$72,686
21100591,524$74,679
22100611,563$76,592
23100631,601$78,428
24100641,637$80,191

How the projection is calculated

The calculator steps forward one month at a time:

  • Sign-ups start at your monthly number and grow by your sign-up growth rate each month.
  • New customers = sign-ups × activation rate.
  • Lost customers = customers at the start of the month × monthly churn.
  • Customers at the end of the month = start + new − lost, and MRR = customers × average revenue per customer.

The growth ceiling

Churn is a share of your base, so it grows as you grow, while flat sign-ups bring the same number of new customers each month. The customer count therefore approaches a ceiling of new customers per month ÷ monthly churn, where the month’s gains and losses cancel out. Spending more on acquisition lifts that ceiling in a straight line; halving churn doubles it.

Reading the levers

The lever panel reruns your projection three times, each with one input 10% better: 10% more sign-ups, a 10% higher activation rate, or 10% less churn. Sign-ups and activation come out equal, because either way you gain the same new customers (unless activation is above about 91%, where it can’t grow a full 10%). Whether that beats churn depends on your horizon and how big your base already is. That is the honest answer to “should we fix onboarding or retention first?”

Where viral growth fits

Sign-up growth per month makes your new sign-ups compound by a fixed percentage, whatever happens to your customer base. That fits growing marketing spend, SEO or a content engine.

Viral growth works differently: your customers bring in new ones, through referrals, invites or word of mouth. So viral sign-ups rise and fall with your customer count, and they stop if your customers leave. Because referrals grow with your base just as churn does, a strong enough loop (each customer bringing in more new customers than churn takes away) removes the growth ceiling altogether.

To approximate a referral loop here, add the sign-ups your current customers bring in today to New sign-ups per month (customers × referral sign-ups per customer per month), and set Sign-up growth per month to roughly how fast your customer base grows. Rerun it as your customer count changes.

What the model leaves out

It is a simple cohort-free model: every customer churns at the same rate, whatever their age, and revenue per customer stays flat. Real churn is usually higher in the first months and lower after, and expansion revenue can make net revenue churn negative. Use it to compare scenarios and find your biggest lever, not as a forecast to the dollar.

Line chart of customers over 60 months with 100 new customers a month: at 4% monthly churn growth flattens towards a ceiling of 2,500 customers, at 2% it keeps climbing towards a ceiling of 5,000.
With 100 new customers a month, customers level off at new customers ÷ churn: about 2,500 at 4% monthly churn, 5,000 at 2%.

Free in Outcomify

Track the funnel behind your activation rate

Activation is usually the cheapest lever to pull. Outcomify’s free key funnels show where new sign-ups drop off before they become customers, and whether what you shipped moved the step. No SDK, no cookies.

Track your activation funnel free

Frequently asked questions

Each month, new sign-ups arrive and your activation rate turns a share of them into customers. At the same time your monthly churn rate removes a share of the customers you had at the start of the month. Customers next month = customers this month − churned + newly activated. MRR is customers × average revenue per customer.

With a steady flow of sign-ups, churn grows with your customer base while new customers stay the same. Growth stops when the two meet: at new customers per month ÷ monthly churn. With 100 new customers a month and 5% churn, that ceiling is 2,000 customers. The only ways through it are more new customers or less churn.

Over a short horizon, acquisition and activation usually win: they add customers right away. Churn reductions compound, so they matter more the longer you look and the bigger your base is. The “What moves the needle” panel compares 10% better on each lever for your own numbers.

Enter your customers today, new sign-ups per month, activation rate and monthly churn, and set the horizon to 12 months. As a rule of thumb, with flat sign-ups you approach new customers per month ÷ monthly churn: the further below that ceiling you start, the faster you grow towards it.

Not directly. Sign-up growth compounds new sign-ups by a fixed percentage, which fits growing marketing or SEO. Viral sign-ups come from your customers, so they rise and fall with your customer count. To approximate a referral loop, add the sign-ups your current customers bring in to new sign-ups per month, set sign-up growth to roughly how fast your customer base grows, and rerun it as that changes.

It depends on who you sell to. Products for small businesses often see 3–7% monthly customer churn; mid-market products 1–2%; enterprise products well under 1%. A 5% monthly churn rate means losing nearly half your customers in a year.

Here it is the share of sign-ups who become paying (or retained, active) customers. In your product it is the moment a new user first gets real value, such as creating a first project or inviting a teammate. Defining it and tracking it as a funnel is often the fastest way to grow.

No. The calculator runs entirely in your browser. Your numbers live only in the page’s address, so “Copy link to this scenario” shares exactly what you see, and nothing is sent anywhere.

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