Inflation calculator

The inflation calculator shows how much of today's amount remains under a flat yearly inflation rate. 10000 at 5% for 10 years has about 6139.13 of purchasing power, and erosion is about 3860.87. You divide the amount by (1 + inflation/100) to the power of years.

Purchasing power = amount ÷ (1 + inflation/100)^years. 10000, 5%, and 10 years leave about 6139. Fisher's real rate is on real rate of return.

Input data

Result

Amount today, Annual inflation (%) and Years. The result shows up here.

How results are calculated

Purchasing power on this page is today's amount divided by (1 + inflation/100)^years. Inflation is flat every year. Erosion is the amount minus that future power, and erosion % is erosion divided by the amount. The calculator does not load official CPI, the consumer price index. You type your own rate.

At 10000, 5%, and 10 years about 6139.13 of purchasing power remains. Erosion is about 3860.87, or 38.61%. 50000 at 3% for 20 years falls to about 27683.79. A short shock: 1000 at 8% for 5 years leaves about 680.58, so about one third is gone.

Type Amount today, Annual inflation (%), and Years. The 10000, 5, and 10 placeholders are the first example. Click Calculate and read purchasing power and erosion. Blank years do not insert a decade.

If you have a nominal rate and want a real one, open real rate of return. There 8% and 3% give about 4.85% by Fisher. Future value can show nominal FV and an optional real view. This calculator asks only for amount, inflation, and years.

Flat 5% for a decade is a scenario, not an official forecast. Different price baskets yield different CPI. Treat 6139 as a class exercise, not a verdict on a paycheck.

Type 10000, 5, and 10. Check about 6139. Then try 8% for 5 years on 1000 to see about 681.

How to use the calculator

  1. In Amount today, type today's sum, for example 10000.
  2. In Annual inflation (%), type a flat rate, for example 5. In Years, type the horizon, for example 10.
  3. Click Calculate. At 10000, 5, and 10, purchasing power should be about 6139.13, and erosion about 3860.87.
  4. Compare erosion % with the second example: 3% for 20 years on 50000 eats about 44.63%.
  5. A nominal rate after inflation lives on real rate of return. That page uses Fisher, not amount division alone.

Purchasing power and erosion at flat inflation

Amount ÷ (1 + inflation/100)^years. 10000 at 5% for 10 years keeps about 6139.13 of purchasing power, and erosion is about 3860.87.

Purchasing power
What remains after compounding inflation. 10000 / 1.05^10 ≈ 6139.13. This is not Fisher’s real rate.
Erosion
The loss of purchasing power. About 3860.87 (38.61%) on the 10000 / 5% / 10-year case. About 319.42 on 1000 at 8% for 5 years.
inflation
The Annual inflation (%) field. 5% for a decade leaves about 6139 of 10000. 3% for 20 years leaves about 27684 of 50000.

Usage examples

Example 1

  • Amount: 10,000
  • Inflation: 5%
  • Years: 10

Purchasing power ≈ 6,139.13
Erosion ≈ 3,860.87 (38.61%)

After a decade at 5% a year, a little over 60% of real value remains.

Example 2

  • Amount: 50,000
  • Inflation: 3%
  • Years: 20

Purchasing power ≈ 27,683.79
Erosion ≈ 22,316.21 (44.63%)

Even “moderate” inflation cuts purchasing power hard over long periods.

Example 3

  • Amount: 1,000
  • Inflation: 8%
  • Years: 5

Purchasing power ≈ 680.58
Erosion ≈ 319.42 (31.94%)

A short horizon at a high rate still removes about one third of value.

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FAQ

How much of 10000 remains after 10 years at 5% inflation?

Purchasing power about 6139.13. Erosion about 3860.87 (38.61%). That is 10000 ÷ 1.05^10.

What about 50000 at 3% for 20 years?

Purchasing power about 27683.79, erosion about 22316.21 (44.63%).

How much does 8% for 5 years take from 1000?

About 680.58 remains, erosion about 319.42 (31.94%).

Is this official CPI?

No. You type your own flat rate. An agency publishes a basket that is not loaded here.

How is this different from the real rate?

The calculator divides an amount by inflation. There you turn a nominal rate and inflation into a Fisher rate, for example 8% and 3% → 4.85%.

Can I type negative inflation?

If the field accepts it, the formula still divides by (1 + i)^n. Deflation would raise purchasing power. Check whether the field allows a minus.

How do I pair this with future value?

FV multiplies capital forward. The calculator divides today's amount to see what it buys at future prices.

Does 5% for 10 years always leave 60%?

In this formula 1 / 1.05^10 ≈ 0.6139, so about 61% remains. Another rate leaves another remainder.

Do blank years mean 10?

No. You must type the horizon. The 10 placeholder is a hint.

Does currency change 6139?

No. 6139 stays 6139. The symbol only labels the same purchasing power.

Knowledge sources

Purchasing power falls by the inflation you type. This is not an official index.

Page updated in 2026.