Black Sea is 1.04× the size of Gansu

The Black Sea (sea) covers about 422,000 km² (163,000 mi²) and Gansu (province) about 406,000 km² (157,000 mi²). Below, both outlines are drawn at one scale and centred on each other. The Black Sea outline is Natural Earth’s, checked against the published area.

422,000km²Black Sea
406,000km²Gansu

200 km

Black Sea
Gansu

What fits

Gansu is 96% of the size of Black Sea.
Black Sea is larger by 16,600 km² (6,420 mi²), which is 4.1% of the area of Gansu.
Measured in Belgiums: Black Sea is about 13.8, Gansu about 13.2.

How they differ

Their centres are about 5,540 km apart.
A standard web map misstates the comparison: Black Sea at 43°N is drawn about 1.9× too large and Gansu at 38°N about 1.6×, so the map shows Black Sea as 1.23× the size of Gansu instead of 1.04×.
Together Black Sea and Gansu cover 828,000 km², close to the size of Namibia (823,000 km², 0.6% smaller).
The gap between them, 16,600 km², is about the size of Eswatini (17,100 km²).
Black Sea's centre is 5.5° of latitude, about 610 km, farther north than Gansu's.
The Black Sea is a sea and ranks 14th of the 42 seas on sizeversus by area.
Gansu is a province of China; it is not drawn with its waters removed, and its measured area is the Natural Earth outline's.
Laid out flat, the Black Sea stretches about 693 km north to south and 1,170 km east to west; Gansu about 1,130 km by 1,390 km.
Poured over Gansu, the 547,000 km³ that Wikidata records for the Black Sea would stand 1,349 m deep.
Our measured 422,000 km² is 3.3% below Wikidata’s published figure of 436,000 km². Published areas of lakes and seas move with the water level and with what is counted, so a few percent is expected.

Who wins on what

Measure	Winner	By
Larger area	Black Sea	1.04×
Farther north	Black Sea	5.5° of latitude
Stretched more on a web map	Black Sea	1.9× against 1.6×

Both against the same yardsticks

Yardstick	Black Sea	Gansu
Belgium 30,700 km²	13.8×	13.2×
United Kingdom 244,000 km²	1.73×	1.66×
Germany 358,000 km²	1.18×	1.13×
Japan 374,000 km²	1.13×	1.09×
France 548,000 km²	0.77×	0.74×
India 3,151,000 km²	0.13×	0.13×
Brazil 8,473,000 km²	0.05×	0.05×
United States 9,447,000 km²	0.04×	0.04×
Russia 16,980,000 km²	0.02×	0.02×

Each figure is the place's area divided by the yardstick's.

Side by side

	Black Sea	Gansu
Is a	Seasea on sizeversus	ProvinceChina
Area, measured	422,000 km²163,000 mi²	406,000 km²157,000 mi²
Area, published	436,000 km²Wikidata	454,000 km²Wikidata
Rank by area	14th of 42seas	–
Greatest depth	2,206 mWikidata	–
Volume	547,000 km³	–
Latitude range	41°N to 47°N	33°N to 43°N
On the shore	6 on the shore	–

Published figures: Wikidata (CC0). A lake or a sea has no legal boundary: the measured area is that of Natural Earth’s outline, and it is shown beside the published one.

Natural Earth’s outlines of Russia, Ukraine, Turkey, Romania, Bulgaria and Georgia lie within 25 km of the outline of the Black 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.

Similar in size to Black Sea

Similar in size to Gansu

More comparisons

Sources and method

Outlines: Lakes and seas: Natural Earth 1:10m physical vectors (public domain), kept only where the measured area is within 10% of the published one. Countries and regions: Natural Earth, 1:10m Admin 0 and Admin 1, public domain.
Boundary: De facto, as drawn by Natural Earth. A lake or a sea has no legal boundary of its own; the outline is a cartographic one.
Area: Measured on the WGS84 ellipsoid from the full-detail outlines, shown rounded. The published figure comes from Wikidata (CC0), fetched 2026-11-11, and is shown beside the measured one.
Drawing: Each outline is projected with an equal-area projection centred on its own centroid, so areas stay true and the two can be laid over each other.
Data built: 2026-11-11

Full method