Free & private

Online Inflation Calculator

Estimate how inflation erodes buying power over time, or compare what an amount of money would be worth between two different years, using your own average annual inflation rate.

CPIYour result will appear hereEnter an amount, a rate and a time period, then select calculate to see buying power change.

Equivalent amount

Real value after adjustment$0

Purchasing power lost0%

Average rate used0%/yr

This calculator uses a single flat average inflation rate that you choose, not actual year-by-year Consumer Price Index data. Real-world inflation varies year to year, so treat this as an estimate rather than a historical record.

How to use the inflation calculator

This free inflation calculator runs entirely in your browser, so nothing you enter is uploaded or stored. Choose whether you want a future projection or a comparison between two calendar years, add your numbers, and select calculate.

1. Pick a mode

Project a future value, or compare buying power between two specific years.

2. Enter your rate

Use a historical average like 3%, or model a higher or lower inflation scenario.

3. Read the breakdown

See the equivalent amount, the real value, and the purchasing power lost.

Understanding inflation and buying power

Inflation is the rate at which prices rise, which means the same amount of money buys a little less each year. This tool compounds a flat average rate you choose over the years you specify, so you can see roughly how much more money you would need later to keep the same buying power, and how much a fixed sum today would really be worth after inflation.

The compounding formula

Future value = amount × (1 + rate)^years. The same formula, applied in reverse, converts a future or past amount back into today's terms.

Worked example

At 3% average inflation, $1,000 today would need to grow to roughly $1,344 in 10 years to have the same buying power.

A simplified model

Real inflation is uneven year to year and varies by category of spending. A flat average rate is useful for planning, not for precise historical accuracy.

How does this inflation calculator work?

It compounds your chosen average annual inflation rate over the number of years you enter, using the formula future value = amount × (1 + rate)^years, then shows the equivalent buying power and how much purchasing power was lost.

What inflation rate should I use?

A commonly used long-run average for the US is around 3% per year, but you can enter any rate to model higher or lower inflation scenarios.

Is this based on real historical CPI data?

No. This calculator applies a single flat average rate that you choose. Actual inflation, measured by the Consumer Price Index, varies from year to year, so this is an estimate, not historical data.

Is this inflation calculator free and private?

Yes. It is free to use, and all calculations run locally in your browser rather than being uploaded or stored by the tool.