Net Worth Attribution Calculator

How is my projected net worth calculated?

You enter a starting balance, monthly inflow and spending, and an assumed annual return. Monthly savings (inflow minus spending) compound with market growth to project a future balance.

Formula

Future value = starting balance × (1 + monthly rate)^months + monthly savings × (((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. An optional currency-drift input (default 0%) is added to the annual rate before conversion.
• Each month, growth is applied to the opening balance first, then that month's savings are added — i.e. end-of-month contributions, the standard future value of an ordinary annuity.

Assumptions and limitations

• Monthly inflow, spending, and the annual return stay constant over the whole horizon.
• Returns are hypothetical illustrations, not predictions — actual market returns vary and can be negative.
• Taxes, fees, and inflation are excluded to keep the model 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. Questions? Talk to the team.

While this educational calculator uses static monthly assumptions, WYNA automates this attribution bridge across all your connected bank, brokerage, and loan accounts. When your net worth changes from one month to the next, WYNA automatically quantifies the exact contribution of market fluctuations, paychecks, internal transfers, and foreign currency exchange rates with verified timestamps.