Sea · counted from 5 pieces
Baltic Sea
Natural Earth draws the Baltic Sea in 5 separate pieces, and this page counts them together. They measure about 381,000 km² (147,000 mi²), and about the same size as Norway. Counted as one, the Baltic Sea would be the 15th largest of the 40 seas on sizeversus.
Natural Earth draws the Baltic Sea as its main basin and cuts out the Gulf of Bothnia, the Gulf of Finland, the Gulf of Riga and the Bay of Mecklenburg. This page adds them back; the Kattegat and the Danish straits are not counted.
- Norway
- Baltic Sea
The numbers
- 381,000km²Area, measured147,000 mi² · Natural Earth outline
- 377,000km²Area, publishedWikidata · agrees within 2%
- 459mGreatest depthWikidata
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 Baltic Sea
- If it counted as one sea, the Baltic Sea would rank 15th of the 40 seas on sizeversus, behind the Black Sea (422,000 km²) and ahead of the Caspian Sea (379,000 km²).
- The largest piece, Main basin (Natural Earth’s Baltic polygon) (207,000 km²), is 54% of the whole; the smallest, Bay of Mecklenburg (5,550 km²), is 1.5%.
- Counted as a country, the Baltic Sea would be larger than 150 of the 212 countries listed on sizeversus and would rank 63rd by area, between Norway (382,000 km²) and Japan (374,000 km²).
- It is larger than 48 of the 51 US states and districts (the biggest of them is Montana, 379,000 km²) and smaller than 3.
- 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 Baltic Sea is about the same size as Montana.
- Wikidata records a greatest depth of 459 m.
- On a standard web map (Web Mercator), a place at 59°N is drawn about 3.7× too large in area, so the Baltic Sea looks bigger there than it is.
- Laid out flat, the Baltic Sea stretches about 1,320 km north to south and 1,160 km east to west.
- Counted as one, the 5 pieces measure 381,000 km². The published figure for the whole, 377,000 km² (Wikidata, for the whole), is 1.1% below it.
The 5 pieces of the Baltic Sea
Natural Earth draws each piece as its own outline; their areas add up to 381,000 km². Largest first.
- Main basin (Natural Earth’s Baltic polygon)207,000 km² · 54%
- Gulf of Bothnia120,000 km² · 32%
- Gulf of Finland30,400 km² · 8.0%
- Gulf of Riga18,200 km² · 4.8%
- Bay of Mecklenburg5,550 km² · 1.5%
About the same size as
Countries
On the shore
Natural Earth’s outlines of Sweden, Finland, Estonia, Russia, Germany, Latvia, Poland and Denmark lie within 25 km of the outline of the Baltic Sea. 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 Baltic Sea ranks
Counted as one, the Baltic Sea would rank 15th of the 40 seas on sizeversus (its own pieces left out).
Compare the Baltic Sea
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%.
- Depth, volume, height
- As recorded in Wikidata; a volume that cannot be right for the area and depth is left out.
- 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