Sri Lanka: this page follows the national index, the Central Bank steers by the Colombo one
Sri Lanka publishes two consumer price indices and they are not interchangeable. The NCPI covers all nine provinces. The CCPI covers the urban areas of Colombo District alone. This calculator uses the national series; the Central Bank of Sri Lanka sets policy against the Colombo one, and every monthly inflation press release you will read is CCPI-based.
They differ most in what people eat. Under the 2021 base, food carries about 39% of the national index against roughly 26% of the Colombo one, because households outside the capital spend a larger share of income on it. When food prices move sharply, and in Sri Lanka they do, the two indices separate widely.
Before 2015 there is no national index at all
The NCPI has only ever existed in two forms, on 2013 and 2021 bases, and it was first released monthly in October 2015. Everything on this page before then is the Colombo index chained on behind it.
That is a real limitation rather than a technicality. A rupee amount from 1990 is being carried forward on a basket weighted for urban Colombo, with food at about a quarter of it. For a household up-country, whose spending looked nothing like that, the conversion understates the inflation actually experienced.
The series starting in 1960 is worth explaining too, because it implies a precision that is not there. 1960 is the World Bank's database convention, the year its development indicators begin for every country. It is not where Sri Lankan price data runs out: the Colombo index itself reaches back to a 1952 base.
2022 is unlike anything else in this calculator
The economic crisis produced the highest inflation in the country's recorded history. Colombo inflation ran at 14.2% in January 2022 and peaked at 69.8% in September; the national index peaked higher still, at 73.7%. Food inflation alone reached 94.9% that month.
Individual prices tell it better than an index does. Over the year, fuel rose about 185%, bread 166%, milk powder 151%, bus fares 140% and electricity 114%. Real wages fell by roughly a fifth across the public and formal private sectors.
A conversion spanning 2022 is therefore dominated by a single year, and the rupee figure it returns will look implausible until you remember what happened. Note also that the data reaches this site by two hops, from the Department of Census and Statistics through the IMF's International Financial Statistics to the World Bank, so the last decimal may differ from the statistics office's own published rate.