Inflation Calculator

How it is calculated

The tool assumes one fixed inflation rate every year and compounds it. The growth factor is factor = (1 + rate ÷ 100)years. Then future cost = amount × factor (what goods worth the amount today will cost after those years), in today's money = amount ÷ factor (what the same amount would buy in today's terms after those years), and total price increase = (factor − 1) × 100. Amount cannot be negative, years must be between 0 and 200 and may be fractional, and the rate must be above −100. A negative rate is accepted and models falling prices, so the increase comes out negative. A rate of 0 or 0 years returns the amount unchanged. Real inflation changes from year to year, so the output is a projection built on your assumption, not a forecast. Money is shown with the site's default currency symbol.

Common mistakes

• Adding the rate each year instead of compounding. 5% for 10 years is a 62.89% increase, not 50%.
• Entering the rate as a decimal such as 0.05. The field is a percentage, so 5 means 5%, while 0.05 means five hundredths of a percent.
• Mixing up the two results. Future cost is what the same goods will cost then; in today's money is what the sum will be worth in current purchasing power.
• Using last year's rate as a certainty for decades. Inflation varies year to year, so a long projection at one fixed rate is only an illustration.
• Entering the years as months, or a total period like 120 for ten years. The field is years and is limited to 200.