acalculator

What is a dollar worth after inflation?

Enter an amount and two months to see how much buying power it has in the other month, with the total and average yearly inflation between them.

Your numbers

Worth in the end month
$198.45

$100.00 in January 2000 has the same buying power as $198.45 in August 2026.

Total inflation
98.45%
Average inflation a year
2.61%
CPI in the start month
168.8
CPI in the end month
334.98
Start month
January 2000
End month
August 2026

Worth in the end month: $198.45. $100.00 in January 2000 has the same buying power as $198.45 in August 2026.

The results are estimates for information only. They are not financial, tax, or legal advice. Check the numbers with your lender or a qualified professional before you decide. Terms of use

How to calculate

Converts dollars from one month to another since 1913 with the US CPI-U (BLS), with the total and yearly inflation.

Example with the default inputs (Amount $100.00, In (start month) January 1, 2000, Is worth in (end month) August 1, 2026): $100.00 in January 2000 has the same buying power as $198.45 in August 2026.

Method: Value = amount × end CPI ÷ start CPI; yearly rate = (CPI ratio)^(12 ÷ months) − 1.

  • CPI-U, all items, US city average, not seasonally adjusted (BLS series CUUR0000SA0).
  • Each date stands for its month; the day is ignored.
  • October 2025 has no CPI (BLS did not collect it).

Machine-readable copies: Markdown, JSON.

Worked examples

Each example is checked against the calculator on every build.

  1. Amount $100.00, In (start month) 2000-01-01, Is worth in (end month) 2026-01-01 gives Worth in the end month $192.68, Total inflation 92.684834%, Average inflation a year 2.554725%, CPI in the start month 168.8, CPI in the end month 325.252.Source: BLS CPI-U (Jan 2000 168.8, Jan 2026 325.252)
  2. Amount $1,000.00, In (start month) 2026-01-15, Is worth in (end month) 2000-01-31 gives Worth in the end month $518.98.Source: BLS CPI-U
  3. Amount $1.00, In (start month) 1913-01-01, Is worth in (end month) 2026-01-01 gives Worth in the end month $33.19, CPI in the start month 9.8.Source: BLS CPI-U (Jan 1913 9.8)

How it works

The data is the monthly CPI-U from BLS (series CUUR0000SA0, all items, US city average, not seasonally adjusted, 1982-84 = 100), from January 1913 to the latest published month. Each date you enter stands for its month; the day is ignored.

With amount A, start month CPI C₁ and end month CPI C₂:

  • Worth in the end month = A × C₂ ÷ C₁.
  • Total inflation = (C₂ ÷ C₁ − 1) × 100%.
  • Months apart: n = (end year − start year) × 12 + (end month − start month), negative when the end month is before the start month.
  • Average inflation a year = ((C₂ ÷ C₁)^(12 ÷ n) − 1) × 100%, shown when n is not 0.

The answer names the two months (for example June 1990). A month outside the data, or October 2025 (not published), gives no answer. Nothing is rounded before display.

Worked examples by hand

$100 from January 2000 to January 2026. C₁ = 168.8, C₂ = 325.252. Worth = 100 × 325.252 ÷ 168.8 = $192.68. Total inflation = 92.68%. n = 312 months; average = 1.926848^(12/312) − 1 = 2.55% a year.

Back in time. $1,000 in January 2026 had the buying power of 1,000 × 168.8 ÷ 325.252 = $518.98 in January 2000.

Since 1913. $1 in January 1913 (CPI 9.8) is worth 325.252 ÷ 9.8 = $33.19 in January 2026.

Across the missing month. $50 in September 2025 (324.8) is worth 50 × 324.122 ÷ 324.8 = $49.90 in November 2025: prices fell 0.21% in those two months.

Other questions people ask

How does an inflation calculator work?

It scales the amount by the ratio of two Consumer Price Index values. The CPI-U was 168.8 in January 2000 and 325.252 in January 2026, so $100 in January 2000 buys what $192.68 bought in January 2026: prices rose 92.68%, about 2.55% a year.

Which CPI does this use?

The Consumer Price Index for All Urban Consumers (CPI-U), all items, US city average, not seasonally adjusted, from the Bureau of Labor Statistics (series CUUR0000SA0). It is the index behind the BLS CPI inflation calculator and most published inflation rates.

Why is there no October 2025?

BLS did not collect October 2025 prices during the 2025 lapse in federal appropriations, and it did not publish a CPI for that month. Pick September or November 2025 instead.

How current is the data?

The page is built with the latest CPI month BLS had published; the result shows that month. BLS publishes each month’s CPI in the middle of the next month.

Is this the same as the Social Security COLA?

No. Social Security cost-of-living adjustments use the CPI-W (urban wage earners) and compare July to September averages. Use the COLA calculator for benefits.