FX & Commodity Almanac

ECB fixings to 16 Oct 2026 · World Bank prices to September 2026

Tool · runs in your browser

How do you calculate the percentage change between two prices?

Subtract the old value from the new one, divide by the old value and multiply by 100. Gold averaged $1,775 an ounce in Sept 2021 and $4,319 in Sept 2026: (4,319 − 1,775) ÷ 1,775 × 100 = +143.3%, or +19.5% a year over five years.

For the compound annual rate. Months ÷ 12.

Example (gold, Sept 2021 → Sept 2026, computed when the page was built):

+143.32%

Difference 2,544.00 · log return 88.92% · compound annual rate 19.46% over 5 years · to get back to 1,775 the price would have to move -58.90%.

Which number should you quote?

  1. Percentage change answers “how much bigger or smaller?” It is not symmetric: a 50% fall needs a 100% rise to recover, which is why the calculator shows the reverse move.
  2. Log return (natural logarithm of new ÷ old) adds up across periods and treats rises and falls symmetrically. Volatility figures on this site are built from log changes. See percent change vs log returns.
  3. Compound annual rate spreads a multi-year change evenly: (new ÷ old)1/years − 1. It describes the start and end points only, not the path in between.
  4. When the values are themselves percentages, such as interest rates, the plain difference is in percentage points; the calculator’s percentage change is a different quantity.

Data for real examples is on the commodity board and the currency board.