How many islands does Indonesia have?

How to get close to this number

Think about what the country is. This is an archipelago nation spanning a distance comparable to the width of a continent, made up entirely of islands rather than containing some. A territory of that extent, in a shallow tropical sea with volcanic and coral formation, produces islands in the thousands rather than the hundreds.

The inhabited figure is the more useful one, and the ratio tells you what most of these islands are: roughly a third are inhabited, which means the majority are small, uninhabited rocks and sandbars. Island counts are always dominated by the smallest category, exactly like the bridge and airport counts elsewhere on this site.

That is also why the number is not fixed. What counts as an island depends on a minimum size threshold and on whether a feature stays above water at high tide, and national surveys have revised the total repeatedly as mapping improved. A figure like this is the output of a survey methodology, which is why the agency and the year are both named.