How big is Madagascar really?
Madagascar covers 587,295 km² (227,000 sq mi). On the usual world map (the Mercator projection) it is drawn close to its true size: it lies near the equator, where the usual world map stretches little.
See Madagascar at its true size on the map →True size vs the map
Both drawn at the same scale. The map keeps shapes but swells everything away from the equator.
Madagascar in numbers
Why the map gets Madagascar wrong
Madagascar lies around 19°S. A Mercator map stretches distances there by about 1.06 times in every direction, so areas come out roughly 1.12 times too big near its middle. Most web maps use this projection because it keeps angles and shapes right for navigation, not because it shows sizes fairly.
In Globegami you can drag a copy of Madagascar anywhere on Earth: it keeps its true size and grows or shrinks on the map as it moves, and you can fold the map back into a globe.
Areas: official totals including inland water (UN Statistics Division via Wikidata). Outlines: Natural Earth. How Globegami works