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Investment Return Calculator

Project deterministic investment growth from a starting value and monthly contributions, with explicit beginning- or end-of-month timing and dollar reconciliation.

Use this result well

Inputs that matter
Starting investment, month-end or month-beginning contribution, fixed nominal annual return scenario, and a whole-year horizon
Output to expect
Projected balance, dollar contributions, modeled growth, growth divided by contributions, annual reconciliation, charts, copy/share/print, and timing comparison
How it works
Deterministic monthly compounding at the nominal annual scenario divided by 12, with each recurring cash flow placed at the explicitly selected beginning or end of month
  • Growth divided by total contributions is a reconciliation ratio, not CAGR, IRR, or time-weighted return.
  • An entered return does not reveal risk tolerance or justify an asset allocation; fees, taxes, inflation, volatility, and losses are omitted unless reflected in the scenario rate.

Choose your path

Built around the job you need to finish

Project a hypothetical investment path from starting value, monthly contributions, constant nominal return, horizon, and beginning/end contribution timing without inferring risk or asset allocation from the entered return.

Recurring investor

See the contribution-versus-growth split for a constant-return scenario.

Enter starting value, monthly contribution, rate, horizon, and timing; inspect the annual table and final balance.

Can explain when deposits occur and treats growth as a scenario rather than an expected market outcome.

Timing comparer

Measure the exact difference between beginning- and end-of-month deposits.

Hold all values constant, switch timing, and compare balances and total contributions.

Gets equal deposits but a defensible one-period growth difference.

Risk-conscious mobile user

Avoid a fake allocation recommendation derived only from a typed return.

Review limitations and sensitivity on a phone, then copy the neutral scenario summary.

No output labels a return assumption conservative/aggressive or prescribes stocks/bonds without risk inputs.

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Reference & details

How it works

Deterministic monthly projection

The entered nominal annual return is divided by 12 and held constant for every month. It is a scenario input, not a forecast or historical performance measure.

Monthly rate = nominal annual return ÷ 12

Contribution timing

Beginning-of-month contributions receive that month's modeled growth; end-of-month contributions do not. Both paths deposit exactly the same dollars, making the timing difference auditable.

Beginning: add contribution, then growth; End: apply growth, then add contribution

Growth is not CAGR or risk-adjusted return

The displayed percentage is modeled growth divided by all contributed dollars. Because contributions occur throughout the period, it is not labeled CAGR, IRR, or time-weighted return. The tool does not infer risk tolerance or prescribe an allocation from the entered rate.

Growth ÷ contributions = modeled dollar growth ÷ total contributed dollars

Updated: August 2026

Example Scenarios

A principal-only deterministic projection using a 7% nominal annual scenario divided monthly.

Initial: $10,000Monthly: $0Rate: 7%Years: 20

Final balance: $40,387.39; contributions: $10,000; modeled growth: $30,387.39

A 20-year, 7% fixed scenario demonstrates how the total reconciles without presenting the input as a market forecast.

Initial: $10,000Monthly: $500Timing: End of monthRate: 7%Years: 20

Final balance: $300,850.72; contributions: $130,000; modeled growth: $170,850.72

With identical inputs, beginning-of-month deposits finish slightly higher because each recurring dollar receives one additional month of modeled growth; contributed dollars remain identical.

Common Mistakes to Avoid

Calling growth divided by contributions CAGR

Recurring cash flows arrive on different dates. This tool labels the ratio literally; use cash-flow IRR or time-weighted returns for genuine performance measurement.

Choosing an asset allocation from a desired return

A typed return does not measure capacity or willingness to take risk. The calculator intentionally removes conservative/aggressive labels and stock/bond prescriptions.

FAQ

No. The same rate is applied every month only to make scenario comparisons deterministic. Actual returns vary, investments can lose value, and fees, taxes, inflation, and withdrawals can materially change outcomes.

Beginning timing adds each contribution before monthly growth; end timing adds it afterward. Beginning deposits therefore receive one extra month of modeled growth.

It is simply modeled growth divided by total contributions. Contributions made throughout the horizon have different holding periods, so the ratio is not a timing-aware annual return.

No. Return input alone cannot establish risk tolerance or a suitable allocation, so the interface does not label scenarios conservative/aggressive or prescribe stocks and bonds.

Keep contribution timing and horizon consistent, then compare final balance, total contributed dollars, and modeled growth. Review fees and taxes separately before making a consequential decision.

About Investment Return Calculator

Explore how a fixed return scenario, time horizon, contribution amount, and cash-flow timing change a projected balance. The result separates contributed dollars from modeled growth and avoids unsupported risk or allocation claims.