Why inflation matters
Investing $10,000 plus $300 a month for 20 years, with prices rising 2.5% a year, here's what each choice would buy in today's money:
- Invested at 7%: about $137,492.
- Savings at 3%: about $86,627 — only a little more than you put in.
- Cash at 0%: about $62,981 — less buying power than you started with.
You'd put in $82,000 in each case. Inflation quietly decides which of those is growth and which is a loss.
How this calculator works
The balance grows each month at the real return, and your monthly amount is held constant in today's money (so it rises with prices in reality). To see the figure your statement would show, multiply by the total price rise — the calculator shows both.
Planning with fixed contributions instead? The ETF Investment Calculator has a “today's money” switch, and the FIRE Calculator uses the same real-return approach.
Frequently asked questions
What is an inflation-adjusted (real) return?
Your return after removing the effect of rising prices. If investments grow 7% in a year and prices rise 2.5%, your buying power grows by about 4.4%. Precisely: (1.07 ÷ 1.025) − 1.
What does 'in today's money' mean?
It expresses a future amount by what it would buy at today's prices. $100,000 in 20 years, with 2.5% inflation, buys roughly what $61,000 buys today.
Is keeping money in a savings account safe from inflation?
Only if its interest rate beats inflation. When savings pay less than prices rise, the balance grows on paper but buys less each year. The table above shows where that line falls for your rate.
Why assume my monthly amount rises with inflation?
It keeps everything comparable. If your salary and savings rise roughly with prices, a constant amount in today's money is a realistic plan — and every figure stays in the same, understandable units.
What inflation rate should I use?
Many central banks target around 2% a year, but actual inflation varies by country and period. Try a higher rate too — the table shows how sensitive your plan is.