Free tool · no sign-up
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 numbers
0% keeps sign-ups flat.
Share of sign-ups who become paying customers.
Share of customers lost each month.
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
| Month | Gained | Lost | Customers | MRR |
|---|---|---|---|---|
| Today | 200 | 9,800 | ||
| 1 | 100 | 8 | 292 | 14,308 |
| 2 | 100 | 12 | 380 | 18,636 |
| 3 | 100 | 15 | 465 | 22,790 |
| 4 | 100 | 19 | 547 | 26,779 |
| 5 | 100 | 22 | 625 | 30,607 |
| 6 | 100 | 25 | 700 | 34,283 |
| 7 | 100 | 28 | 772 | 37,812 |
| 8 | 100 | 31 | 841 | 41,199 |
| 9 | 100 | 34 | 907 | 44,451 |
| 10 | 100 | 36 | 971 | 47,573 |
| 11 | 100 | 39 | 1,032 | 50,570 |
| 12 | 100 | 41 | 1,091 | 53,448 |
| 13 | 100 | 44 | 1,147 | 56,210 |
| 14 | 100 | 46 | 1,201 | 58,861 |
| 15 | 100 | 48 | 1,253 | 61,407 |
| 16 | 100 | 50 | 1,303 | 63,851 |
| 17 | 100 | 52 | 1,351 | 66,197 |
| 18 | 100 | 54 | 1,397 | 68,449 |
| 19 | 100 | 56 | 1,441 | 70,611 |
| 20 | 100 | 58 | 1,483 | 72,686 |
| 21 | 100 | 59 | 1,524 | 74,679 |
| 22 | 100 | 61 | 1,563 | 76,592 |
| 23 | 100 | 63 | 1,601 | 78,428 |
| 24 | 100 | 64 | 1,637 | 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?”
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.
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.