Inflation Calculator
See how inflation erodes your money over time — what today's dollars will buy in the future, and what past dollars are worth today.
Enter any amount, a number of years, and your own inflation-rate estimate. The calculator shows the future purchasing power of today's dollars and, in reverse, what an amount from the past would equal in today's money. Every result is labeled an estimate because inflation never moves at a constant rate.
How to use this calculator
- Step 1: Enter the dollar amount you want to analyze.
- Step 2: Enter the number of years (forward or backward).
- Step 3: Enter your own annual inflation-rate estimate — 3.0 is a common long-run starting point.
- Step 4: Click Calculate to see both the future purchasing power and the past value in today's dollars.
- Step 5: Re-run with higher and lower rates to see how much the answer depends on the assumption.
The formula
Future purchasing power = amount / (1 + rate)^years; Past value today = amount × (1 + rate)^years
Worked example
$50,000 at a constant 3% inflation for 20 years: the future purchasing power is $27,683.79, meaning today's $50,000 buys what about $90,305.56 will buy in 20 years (equivalently, past $50,000 equals $90,305.56 in today's dollars).
Frequently Asked Questions
How does the inflation calculator work?
It applies compound growth at your chosen annual rate. Future purchasing power divides your amount by (1 + rate)^years, showing what today's dollars will still buy. Past value in today's dollars multiplies by (1 + rate)^years, showing what an old amount equals now. For example, at 3% for 10 years, $100 today buys what $74.41 will buy, and a past $100 equals about $134.39 today.
What inflation rate should I enter?
That is up to you — the tool deliberately does not hardcode one. Many people use a long-run average such as 3%, or the recent rate published by the Bureau of Labor Statistics for their own country. Try a few rates (say 2%, 3%, and 5%) to see how sensitive long-horizon plans like retirement are to the assumption.
Why is the result only an estimate?
Inflation never moves at a constant rate year after year, and your personal inflation rate depends on what you actually buy — housing, healthcare, and education have all risen faster than the headline average. The calculator shows the pure math of a constant rate, which is useful for planning but not a prediction.
What is the difference between future purchasing power and past value?
They are two directions of the same math. Future purchasing power looks forward: it shrinks today's amount to show its buying power after years of inflation. Past value in today's dollars looks backward: it grows an old amount, which is useful for comparing a salary, house price, or savings balance from years ago against today's prices.