How is future purchasing power calculated?

Future value = Amount × (1 + rate/100)^years. For example, $1,000 at 3% inflation for 10 years becomes $1,000 × 1.03^10 ≈ $1,344 — meaning you would need $1,344 in the future to buy what $1,000 buys today.

How is past purchasing power calculated?

Past amount in today's dollars = Amount × (1 + rate/100)^years. This compounds a historical price or income forward using the assumed steady inflation rate.

What inflation rate should I use?

The US long-run average CPI inflation is roughly 3% per year. The 2010s averaged about 2%, while the early 2020s saw spikes above 8%. For conservative planning, 3–4% is a common assumption.

Does this use real CPI data?

No — this tool uses a fixed annual rate you provide, not live CPI data. For official historical CPI figures, use the US Bureau of Labor Statistics CPI calculator.

How do I reverse the inflation calculation?

Switch to "Past value" mode. Enter a historical amount, the assumed annual rate, and the number of years; the tool compounds it forward to show its equivalent in today's dollars.

How much is $100 from 20 years ago worth today?

It depends on the inflation that actually happened. At an average of 2.5% a year, $100 from 20 years ago equals $100 × 1.025^20 = $163.86 today. Switch to Past value mode, enter 100, 2.5 and 20 to see each year. For the actual US figure between two years, use the CPI Inflation Calculator, which works from Consumer Price Index data instead of an assumed rate.

How fast do prices double with inflation?

Use the rule of 72: divide 72 by the yearly inflation rate. At 3% prices double in about 24 years (the exact figure is 23.4 years), and at 6% in about 12 years.

Inflation Calculator

Enter an amount, an annual inflation rate, and a number of years to instantly see how purchasing power changes — forward or backward in time.

Inflation raises prices by a percentage each year, so the amount needed to buy the same things grows as amount × (1 + rate)^years.

Inflation Inputs

Mode

Amount

Annual Inflation Rate

Number of Years

Currency Symbol

Fill in the inputs on the left and click Calculate

Equivalent in N years

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Starting Amount

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Change

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Purchasing Power

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Year	Equivalent Value	Cumulative Change

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Quick answer

Inflation raises prices by a percentage each year, so the amount needed to buy the same things grows as amount × (1 + rate)^years. At 3% a year, $1,000 today has to become $1,343.92 in 10 years, and $1,000 left in cash buys only about $744 of today's goods after those 10 years.

Examples

Annual inflation	$1,000 in 10 years	$1,000 in 20 years
2%	$1,218.99	$1,485.95
3%	$1,343.92	$1,806.11
5%	$1,628.89	$2,653.30

Enter your amount, rate and years for the exact value and a year-by-year table.

Summary

An inflation calculator shows how the purchasing power of money changes over time. Forward mode projects what today's money will be worth after years of inflation; reverse mode converts a past dollar amount into today's equivalent. It applies a fixed annual rate you set and lists a year-by-year breakdown so you can see the erosion at each step.

How it works

Choose "Future value" to calculate the future amount needed to match today's purchasing power, or "Past value" to find what an old amount equals today.
Enter the starting amount in the Amount field.
Set the annual inflation rate (the historical US average is roughly 3%).
Enter the number of years.
Optionally choose a currency symbol for the display.
Click Calculate to see the result, purchasing-power change, and a year-by-year breakdown table.

Use cases

Calculate how much money you will need in 20 years to match $50,000 of purchasing power today at 3% inflation.
Understand what a 1990 salary of $40,000 is worth in today's dollars.
Plan a long-term budget by seeing how fixed costs erode under sustained inflation.
Compare the real cost of goods across different decades.

Frequently Asked Questions

Last updated: 2026-05-23 · Reviewed by Nham Vu