Investment Calculator
Investment Terms
Calculation Results
| Ending Balance (Nominal) | — |
|---|---|
| Total Principal Invested | — |
| Total Return (Gain) | — |
How to Use This Investment Calculator
Retirement projections on a spreadsheet always break when someone asks "but what about inflation?" This calculator handles that in one pass—starting balance, expected return, recurring contributions, and an optional inflation haircut so you see nominal dollars and real purchasing power side by side.
- Enter starting amount and expected annual return. Use a long-run average aligned with your asset allocation, not last year's headline return.
- Set investment term in years. Match your horizon—college fund, house down payment, or retirement window.
- Choose compounding frequency. Monthly is typical for diversified portfolios; daily or continuous options are available for comparison.
- Add optional contributions. Enter deposit amount, frequency, and whether money moves at the beginning or end of each period.
- Enter inflation (optional). A non-zero rate shows real (inflation-adjusted) value alongside nominal ending balance.
- Press Calculate. Review ending balance, total invested, interest/growth earned, real value, and the yearly schedule.
Compare steady-rate math with actual cash flows using the IRR Calculator, or isolate compound growth with the Compound Interest Calculator.
Investment Formulas and Practical Applications
Portfolio growth here follows standard time-value-of-money logic: your starting capital and each contribution compound at the entered return rate. Inflation is applied separately to translate nominal ending wealth into today's dollars—like asking whether a future pile of cash still buys the same groceries.
Future value with contributions
FV = PV(1 + r/n)nt + PMT × [((1 + r/n)nt − 1) / (r/n)]
With $25,000 starting, 7% return compounded monthly, $500/month for 20 years, nominal ending balance lands near $318,000 before inflation.
Real (inflation-adjusted) value
Real Value = Nominal FV / (1 + inflation)t
At 3% annual inflation over the same 20 years, that $318,000 nominal figure equates to roughly $176,000 in today's purchasing power—a reminder that headline account balances overstate what you can actually spend later.
Frequently Asked Questions
How does the Investment Calculator handle inflation?
Enter an optional annual inflation rate. The calculator shows both nominal future value and inflation-adjusted real value so you can compare portfolio growth to purchasing power.
What return rate should I use?
Use a long-run average that matches your asset mix—conservative portfolios might use 4–5%, balanced 6–7%, aggressive 8%+. This is a planning assumption, not a guarantee.
How do periodic contributions affect growth?
Each deposit compounds along with your starting amount. Beginning-of-period timing earns slightly more than end-of-period because deposits sit in the account longer.
What compounding frequencies are supported?
Monthly, quarterly, semiannual, annual, daily, and continuous compounding are available. More frequent compounding raises the ending balance at the same nominal return.
Does this account for market volatility?
No. The calculator assumes a steady annual return. Real portfolios fluctuate year to year; use the Average Return Calculator or IRR Calculator to analyze actual performance.