7,100 is the example result. Read it using the units and relationship stated below.
App Development Cost uses number of key screens, design cost per screen, development cost per screen.
Separating growth, retention and subscription capacity
For app development cost, the relationship is Result = [Number of key screens] × ([Design cost per screen] + [Development cost per screen]) + [QA and launch cost]. The amount depends on the supplied number of key screens, design cost per screen, rather than a live market price or a value imported from another record. Recurring revenue should be compared across the same starting cohort. Expansion, contraction and churn change retention in different directions. Adding new customers to a retained-customer calculation can conceal losses in the original population.
What the model includes
Result = [Number of key screens] × ([Design cost per screen] + [Development cost per screen]) + [QA and launch cost] Match the unit of the plan: users, seats, subscriptions and revenue are not interchangeable. A purchased seat can remain unused even when the invoice is fully paid. Annual prepayment also changes cash timing without changing monthly recurring value. Read the result beside the renewal schedule and account concentration. A short measurement window may miss seasonal usage or contracts that have not yet reached their renewal date.
Example with the supplied inputs
Number of key screens: 20; Design cost per screen: 75; Development cost per screen: 180; QA and launch cost: 2000. Result: 7,100. The values are illustrative.
Compare one changed input
Number of key screens changes from 20 to 22. The result becomes 7,610. All other inputs remain fixed.
Calculation rule
Result = [Number of key screens] × ([Design cost per screen] + [Development cost per screen]) + [QA and launch cost]
Inputs and output
| Input | Example value | Entry convention |
|---|---|---|
| Number of key screens | 20 | Use the source quantity represented by number of key screens. Keep the counted population fixed and avoid mixing a unit value with a period total. |
| Design cost per screen | 75 | Use design cost per screen on the currency and period basis shown by the formula. Keep gross amounts, net amounts and unit amounts distinct; the page does not fetch a price or exchange rate. |
| Development cost per screen | 180 | Use development cost per screen on the currency and period basis shown by the formula. Keep gross amounts, net amounts and unit amounts distinct; the page does not fetch a price or exchange rate. |
| QA and launch cost | 2000 | Use qa and launch cost on the currency and period basis shown by the formula. Keep gross amounts, net amounts and unit amounts distinct; the page does not fetch a price or exchange rate. |
Output: 7,100 is the example result. Read it using the units and relationship stated below. Use the formula to distinguish a cash amount, count, percentage or ratio.
How to use the page
Collect the inputs
Gather Number of key screens, Design cost per screen, Development cost per screen. Use one period and the units shown in the form.
Run the calculation
Enter the values and select the action. The calculation rule above explains how the inputs produce the result.
Compare a scenario
Change Number of key screens on its own, keeping the other inputs fixed. Read both results before changing another assumption.
Worked example
With the example inputs listed above, the result is 7,100.
Change Number of key screens from 20 to 22 while keeping every other value fixed. The result becomes 7,610. This comparison isolates that input; it does not forecast how other variables will respond.
Check the stated formula, units and limits before using the result in a decision.
Keep the displayed formula, input units and model scope with the result. Corrections or questions can be sent through the request section on this page.
Content updated: October 11, 2026