Investment Calculator
Choose Investment growth to project a portfolio forward, or Historical dollar value to see what a real amount from a past year is worth in another year using actual CPI data - enter your numbers below.
Last updated: September 22, 2026
Frequently asked questions
Why does inflation matter for investment projections?
A dollar in 20 years buys less than a dollar today - showing only the nominal future value overstates how much better off you'll actually be, so adjusting for inflation gives a more honest picture.
What return rate should I use for an investment calculator?
7% is a commonly used long-term average for a diversified stock portfolio after inflation is roughly accounted for in nominal terms, but actual returns vary significantly year to year - use a conservative estimate for planning.
How does contribution frequency affect long-term growth?
More frequent contributions (monthly vs. annually) let your money start compounding sooner on average, which produces a modestly higher final balance for the same total amount contributed over the same period.
What's a realistic average annual return to assume for long-term projections?
Historically, diversified stock market index funds have averaged roughly 7-10% annual returns before inflation over multi-decade periods, though any single year can vary wildly. Using a more conservative estimate (6-7%) for planning purposes accounts for volatility and fees better than assuming a best-case average every year.
What's the difference between the nominal and inflation-adjusted future value shown?
The nominal value is the raw dollar total your investment grows to at the stated return rate. The inflation-adjusted (real) value discounts that nominal figure by the inflation rate over the same period, showing what that future amount is actually worth in today's purchasing power.
If I invest $10,000 with $300/month contributions at 7% for 20 years, roughly what's the nominal result?
Growing the $10,000 lump sum plus $300 monthly contributions at 7% annually compounded monthly for 20 years lands around $195,000 nominal - the exact figure depends on the compounding assumptions, but contributions dominate lump-sum growth over a horizon that long at typical contribution levels.
Is this the same as a compound interest calculator?
It builds on the same compounding math but adds two things a basic compound interest calculator doesn't: regular monthly contributions on top of the starting balance, and an inflation adjustment to show real (purchasing-power) value alongside the nominal total.
What's the difference between 'growth mode' and 'historical dollar value mode'?
Growth mode projects a hypothetical portfolio forward using an assumed return rate you choose. Historical dollar value mode instead uses real, published CPI-U inflation data to answer a different question: what a specific real amount of money from one actual year is worth in another year's dollars.
How accurate is the historical dollar value mode?
It's based on actual published CPI-U annual averages, not an assumed rate, but the underlying table only lists roughly every 5-10 years rather than every single year - values for years in between are linearly interpolated, so treat the result as a close estimate rather than the exact official figure for that year.
What is CPI-U?
The Consumer Price Index for All Urban Consumers, published by the US Bureau of Labor Statistics - it tracks the average change in prices paid by urban consumers for a broad basket of goods and services over time, and is the standard reference for measuring US inflation.
What was $100 in 1990 worth in 2025?
Using CPI-U data, about $245 in 2025 dollars - prices roughly two-and-a-half times over that 35-year span. Enter 100, 1990, and 2025 in Historical dollar value mode above to see the exact figure and the cumulative inflation percentage.