Subscription Cost Calculator

How is the subscription projection calculated?

You enter one monthly subscription total and an assumed annual return. We show two numbers: what you would pay directly, and what those payments might grow to if invested monthly instead.

Formulas

• Direct spend = monthly amount × 12 × years
• Illustrative invested value = monthly amount × (((1 + monthly rate)^months − 1) / monthly rate)

Rate conversion and timing

• Your annual return is converted to a monthly rate by dividing by 12 — for example, 7% per year becomes about 0.583% per month.
• Each monthly amount is treated as invested at month-end — i.e. end-of-month contributions, the standard future value of an ordinary annuity.

Assumptions and limitations

• Monthly spending and the return rate stay constant; contributions happen at month-end.
• Growth figures are hypothetical illustrations, not guarantees — real investments vary and can lose value.
• Taxes, fees, and inflation are excluded to keep the comparison simple.
• Educational estimates only, not financial advice.

Sources and review

The compounding math follows the standard future value of an annuity, as explained by the U.S. Securities and Exchange Commission's compound interest calculator and the future value formula. Reviewed by the WYNA editorial and engineering team. Last reviewed September 2026. Compare with the net worth calculator.

WYNA identifies repeating cadence patterns, trial expirations, and unexpected price increases across all connected accounts without accessing your payment credentials or selling your transaction history to data brokers.