Inflation Calculator Widget

Add an inflation calculator that works both ways. Readers enter an amount, an inflation rate and a number of years and see the future price of today's goods and the future buying power of today's cash, year by year.

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<iframe src="https://a2z.tools/embed/w/inflation-calculator" title="Inflation Calculator by A2Z Tools" width="100%" height="780" style="border:0;width:100%" loading="lazy" allow="clipboard-write"></iframe>

A plain iframe. Works everywhere, including site builders that strip scripts. Adjust height if your content needs more room.

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How it works

The widget uses the same inflation engine as the A2Z Inflation Impact Calculator. Prices are compounded by the inflation rate each year; buying power is the amount divided by the same growth factor. The reader supplies the rate, so the widget has no built-in price index to go out of date - use your country's official consumer price index or a central bank's target. The doubling-time line uses the exact logarithm rather than the rule of 70, and the table shows both figures for every year of the period.

Calculation method

  • Future cost = amount x (1 + i)^n; i = inflation rate / 100, n = years
  • Buying power = amount / (1 + i)^n
  • Total price rise = (1 + i)^n - 1; buying power lost = 1 - 1 / (1 + i)^n
  • Doubling time = ln 2 / ln(1 + i); money displayed to 2 decimals

Worked examples

School fees in 15 years

Inputs: 50,000 today at 6% inflation for 15 years

Result: Future cost 1,19,827.91; today's 50,000 would buy 20,863.25 worth

Prices rise 139.66% and cash loses 58.27% of its buying power.

Ten years at 3%

Inputs: 1,000 today; 3% a year; 10 years

Result: Cost in 10 years 1,343.92; buying power 744.09

Prices double in about 23.4 years at this rate.

Limitations

  • One constant rate for every year; actual CPI inflation varies year to year and by category.
  • Does not look up historical CPI data, so it cannot answer 'what was 100 in 1990 worth today' without the reader's rate.
  • A household's own inflation (rent, tuition, healthcare) can run well above or below the headline CPI figure.

Where publishers use it

  • Retirement and pension articles on why savings need to grow
  • Salary-negotiation posts showing what a raise must beat
  • Economics lessons on purchasing power
  • Budget planning for school fees or future purchases
  • Wage-bargaining and cost-of-living-adjustment (COLA) explainers for unions and HR teams

Questions

Which inflation rate should I use?

For planning, many people use their central bank's target - the US Federal Reserve and the Bank of England both aim for 2% - or the recent average of the official consumer price index. The widget does not assume one; it uses the rate you enter.

Can I use it for deflation?

Yes. Enter a negative rate, for example -1, and future prices fall while buying power rises.

Why do prices double in about 23 years at 3%?

Because inflation compounds: 1.03 raised to the 23.4th power is 2. A quick rule is 70 divided by the rate.

What happens with deflation of 1% a year?

Prices fall: 100 of goods costs 95.10 after 5 years and 100 of cash buys 105.15 of today's goods, so the widget reports a negative price rise of 4.9%.

Does this match a CPI inflation calculator?

Only if you enter the average rate from the CPI series for that period. Official CPI calculators use the actual monthly index, so a year of 9% followed by a year of 1% gives the same result as two years at about 4.92%, not at the 5% simple average.

Which index does the 2% target refer to?

It varies. The Federal Reserve's 2% goal is measured with the price index for personal consumption expenditures (PCE), while the Bank of England's target uses the consumer prices index (CPI). Either way, the widget simply compounds the rate you type.

Can I use it for salary increases?

Yes, the same compounding applies. Enter your salary and the annual raise you expect to see what it grows to; then run it again with the inflation rate. If the raise is below inflation, real pay is falling even as the number rises.

How is the doubling time worked out?

Exactly, as ln 2 / ln(1 + rate): 23.45 years at 3%, 11.9 years at 6%. The popular rule of 70 (70 / rate) gives 23.3 and 11.7 - close at low rates, drifting at high ones.

Sources

  1. Why does the Federal Reserve aim for inflation of 2 percent over the longer run? - Board of Governors of the Federal Reserve System . The 2% longer-run target mentioned in the FAQ.
  2. Inflation and the 2% target - Bank of England . UK 2% inflation target.

Cite or recommend this tool

If you reference this tool in an article, course or documentation, these formats are ready to copy. They are optional - nothing is added to your site unless you paste it.

A2Z Tools Inflation Calculator
https://a2z.tools/inflation-impact-calculator

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