Future value and present value
Future value projects what today's money could become at an assumed rate. Present value discounts a future amount back to today. Both depend heavily on the selected rate and time period.
Nominal vs real return
Nominal return is the growth rate before inflation adjustment. Real return estimates growth in purchasing-power terms. Retirement planning often needs both views: nominal account balances and real spending power.
Contribution timing
Recurring deposits can be assumed at the beginning or end of each period. The difference is small over short periods but meaningful over long horizons. The calculator needs to state the assumption.
Risk and limitations
- Historical returns are not guaranteed future returns.
- Fees, taxes and inflation reduce spendable results.
- Average annual return does not show volatility.
- Retirement withdrawals are affected by return order, not just average return.
Nominal and real retirement examples
A 6% nominal return with 2% inflation is not a 4% real return exactly. The more precise formula is (1.06 / 1.02) - 1, which is about 3.92%. Over 30 years, the difference between nominal and real assumptions can materially change whether a plan appears on track.
Retirement estimates are clearer when they make contribution timing, inflation, fees, tax treatment and withdrawal assumptions visible. A 500 monthly contribution at 5% for 30 years is a different result if contributions occur at the beginning of each month instead of the end.
Useful calculators
- Interest Calculator
- Future Value Calculator
- Present Value Calculator
- Retirement Calculator
- Investment and Retirement Formulas
FAQ
Should I use nominal or real return?
Use nominal return for account balances and real return for purchasing-power comparisons.
Why do investment calculators produce different answers?
They may use different compounding frequency, contribution timing, inflation adjustment or fee assumptions.
Is a retirement projection financial advice?
No. It is a scenario estimate based on inputs and assumptions.
References
- Investor.gov: financial tools and calculators, accessed 2026-05-16.
Last reviewed: 2026-05-16.