A cikin girmansa, tsawon Arewa-ta Kudu na tafkin ya kai kilomita 40 (25 mi) kuma fadin Gabas-Yamma yana da kusan kilomita 7<unk>8 (4.3<unk>5.0 mi). Yankin sa ya kai kilomita murabba'i 250 (97 sq mi), wanda ya sa ya zama tafkin tsaunuka na biyu mafi girma a China, bayan Tafkin Dianchi. Kewayonsa ya kai kilomita 116 (72 mi), matsakaicin zurfinsa ya kai mita 11 (36 ft) kuma jimlar damar adana mita biliyan 2.5 (2,000,000 acre⋅ft). Tambaya: Menene girman tafkin Erhai?
Tsayin Arewa zuwa Kudu na tafkin ya kai kilomita 40 (25 mi) kuma faɗin Gabas zuwa Yamma ya kai kilomita 7<unk>8 (4.3<unk>5.0 mi).