THE NUMBERS, EXPLAINED
How to use this calculator.
Observed whole-month payback, no interpolation or future forecast. Negative later contributions can reverse an earlier recovery.
Start with your inputs
Enter cohort acquisition cost (currency), net cohort contributions by month (currency). Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Cohort acquisition cost (currency) | 1000 |
| Net cohort contributions by month (currency) | 200,300,600 |
A worked example
With the example inputs above, cumulative cohort contributions (currency) is 200, 500, 1100. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Cumulative cohort contributions (currency) | 200, 500, 1100 |
| First end-month recovering acquisition cost | 3 |
| Final net return after acquisition (currency) | 100 |
How this is calculated
Cumulative cohort contributions (currency)
Accumulate observed net contribution month by month.
First end-month recovering acquisition cost
Find the first observed cumulative balance covering acquisition cost.
Final net return after acquisition (currency)
Deduct acquisition cost from all supplied monthly contribution.
Symbols and units
- a
- Cohort acquisition cost (currency)
- b
- Net cohort contributions by month (currency)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions and limits
Observed whole-month payback, no interpolation or future forecast. Negative later contributions can reverse an earlier recovery.
Calculations use the values you enter. Blank or invalid inputs show an error instead of silently substituting zero. Results are displayed to useful precision; calculations retain the underlying numeric precision.
Questions about this tool
What does the result tell me?
Cumulative cohort contributions (currency); First end-month recovering acquisition cost; Final net return after acquisition (currency). The result applies to the method and inputs described above. Check the units and assumptions before using it in a decision.
Why might another calculator differ?
Differences in units, rounding, timing or model definitions can produce different answers. Compare the input definitions and the method, rather than only the final number. For this tool: Observed whole-month payback, no interpolation or future forecast. Negative later contributions can reverse an earlier recovery.
Are my inputs stored or sent to AI?
Calculations on this page happen in your browser. The separate AI question finder sends its submitted conversation to OpenAI; these calculator fields are not sent. Favourites and recent tool names are stored locally. A shared link contains the inputs you choose to include.
Further reading
OpenStax: Calculate a Break-Even Point in Units and Dollars ↗
Background reading; this does not imply endorsement or independent review of SumFizz.
Review status
Software example and browser checks are recorded in our quality report. No external expert review is claimed. Created with coding assistance; calculations run as ordinary browser code.
Read the quality report →