Reef
Great Barrier Reef
Natural Earth’s outline of the Great Barrier Reef measures about 348,000 km² (135,000 mi²), the 17th largest of the 42 seas on sizeversus, and about the same size as Germany.
200 km
- Germany
- Great Barrier Reef
The numbers
- 348,000km²Area, measured135,000 mi² · Natural Earth outline
- 348,000km²Area, publishedWikidata · agrees within 2%
The area is measured from the outline drawn above, on the WGS84 ellipsoid; the published figure is shown beside it, and a water body is kept only if the two are within 10%.
What the numbers say about the Great Barrier Reef
- The Arabian Sea, the largest of the 42 seas ranked on sizeversus, is 11.9× the size of the Great Barrier Reef; the Great Barrier Reef ranks 17th.
- The Great Barrier Reef sits between the Yellow Sea (377,000 km²) and the Bismarck Sea (331,000 km²) in the ranking.
- Counted as a country, the Great Barrier Reef would be larger than 148 of the 212 countries listed on sizeversus and would rank 65th by area, between Germany (358,000 km²) and the Republic of the Congo (345,000 km²).
- It is larger than 47 of the 51 US states and districts (the biggest of them is New Mexico, 315,000 km²) and smaller than 4.
- It is larger than 23 of the 31 provinces and regions of China (the biggest of them is Guangxi, 237,000 km²) and smaller than 8.
- The closest US state is Montana (379,000 km²): the Great Barrier Reef is 92% of the size of Montana.
- The Great Barrier Reef lies at 18°S, close to the equator, where a standard web map (Web Mercator) is nearly true to size: it inflates area by only about 1.1×.
- Laid out flat, the Great Barrier Reef stretches about 1,580 km north to south and 1,130 km east to west.
- Wikidata’s published figure of 348,000 km² agrees with our measured 348,000 km², to within 2%.
About the same size as
Countries
On the shore
Natural Earth’s outlines of Australia lie within 25 km of the outline of the Great Barrier Reef. That is what its geometry says, and it is not a statement about who owns the water or where any border runs in it.
Where the Great Barrier Reef ranks
The Great Barrier Reef is the 17th largest of the 42 seas on sizeversus, ranked by measured area.
Compare the Great Barrier Reef
Share this outline
Sources and method
- Outline
- Natural Earth, 1:10m Marine Areas (geography_marine_polys), public domain (Marine Areas (geography_marine_polys)). Natural Earth draws marine areas for labels and cuts them at named sub-areas; the outline is kept because its area matches the published one.
- Boundary
- A lake or a sea has no legal boundary of its own. The outline is a cartographic one, and the page says so by showing the measured area beside the published one.
- Area basis
- Measured outline: computed on the WGS84 ellipsoid from the full-detail outline and shown rounded. Published figure: Wikidata (CC0), fetched 2026-11-11. An outline is kept within 10% of the published figure and matched to other places automatically within 5%.
- Shore
- Countries whose Natural Earth outline contains or comes close to the water's outline; computed, not a statement of ownership.
- Drawing
- Each outline is projected with an equal-area projection centred on its own centroid, so areas stay true and two can be laid over each other.
- Data built
- 2026-11-11