Calculate portfolio projection

Project an investment balance from starting capital, end-of-month deposits, and a fixed nominal annual return.

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ToolPortfolio Projection Calculator
Input
Output
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How it works

The nominal annual return is divided by 12, then applied to the existing balance once for each rounded month before that month's contribution is deposited. Contributions therefore begin earning in the following month; the displayed growth removes both the starting balance and every deposit from the final projection.

Formula
next balance = current balance × (1 + annual return ÷ 12) + monthly contribution
  • No return is inferred, and the entered constant rate is a scenario rather than a market forecast.
  • Fees, tax, inflation, and changing monthly returns are excluded from the projected balance.

Worked example

Calculate portfolio projection
Input
											Starting balance: 10000
Monthly contribution: 500
Annual return percent: 6
Years: 10
Output
												Projected balance: 100133.64
Total contributed: 70000
Estimated growth: 30133.64
Assumption: Constant monthly compounding; taxes, fees, volatility and inflation are excluded.

When to use this

Brokerage contribution plans, pension reviews, and investment policy statements use a current balance, monthly deposit, and horizon to test a return scenario before adding fees, tax, and inflation.

Edge cases

  • A duration with part of a year is rounded to the nearest whole month before deposits and returns are applied.
  • Because deposits occur at month end, the first monthly contribution earns no return during its deposit month.
  • A smooth fixed return omits sequence-of-returns risk: two portfolios with the same average return can finish differently when gains and losses occur in a different order.

References