How do I calculate what something will cost in the future?

Multiply today's amount by (1 + inflation rate) raised to the number of years — the same compounding formula behind interest, just working against your money instead of for it. This calculator runs that formula at a rate you set, defaulted to the long-run historical U.S. average.

What inflation rate should I use?

Roughly 3.2% mirrors the long-run historical average U.S. CPI rate and is a reasonable planning default, but any given decade can run well above or below it. Try a range of rates rather than trusting a single number for a long horizon.

How much purchasing power does a dollar lose over time?

At the same 3.2% average, a dollar loses roughly half its purchasing power over about 22 years. This calculator reports that loss directly for whatever amount and horizon you enter, rather than leaving you to work the compounding out by hand.

Calculator

Inflation Calculator

Inflation is easy to know about and easy to forget to apply to your own numbers. Enter an amount, a number of years, and a rate — defaulted to the long-run historical average — and see both directions at once: what that amount will cost in the future, and what it's worth right now if it's a figure quoted from the past.

Results

In the future

Future cost

$0.00

Cumulative inflation

0.0%

In today's dollars

Remaining purchasing power

$0.00

Purchasing power lost

$0.00

Amount & horizon

Amount

Number of years

Annual inflation rate

Reading the two directions

In the future answers: if this amount is what something costs today, what will it cost after this many years of inflation?

In today's dollars answers the mirror question: if this amount is a figure from that many years ago, what is it actually worth in today's purchasing power?

Both readings come from the exact same formula — just applied in opposite directions.

How this is calculated

For educational purposes only. Results are estimates and do not constitute financial, tax, or legal advice. Consult a qualified professional before making any financial decisions.

How to use it

Enter a dollar amount, a number of years, and an annual inflation rate — prefilled at 3.2%, the long-run historical U.S. average.

The results show both directions at once: what that amount will cost in the future, and what it's actually worth today if it's a figure quoted from that many years ago.

Scroll down for a year-by-year table of the future-cost equivalent, and Show the math for the formula worked with your own numbers.

Assumptions

Assumes a single, constant inflation rate for the entire period — real-world inflation varies year to year, so this is a simplified projection, not a forecast.
"In the future" and "in today's dollars" are the same compounding formula applied in opposite directions, not two independent calculations.
A negative rate models deflation — purchasing power grows instead of shrinking — which is unusual but not disallowed.
The year-by-year schedule is capped at 100 rows.

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