This tool uses the World Bank’s annual CPI series (Consumer price index, 2010=100) for Sri Lanka (1960 → latest available year) to adjust a price across years:
pricetoYear = pricefromYear × (CPItoYear / CPIfromYear)
It’s best for long-run comparisons. If you need monthly, local indices (CCPI/NCPI, 2021=100), you’ll need a different series and a re-base.
Inflation is a quantitative measure of the rate at which the average price level of a basket of selected goods and services in an economy increases over a period of time.
Read more — Investopedia: Inflation