Kalasin's 2026 population is now estimated at 558,690. In 1950, the population of Kalasin was 8,095. Kalasin has grown by 6,808 in the last year, which represents a 1.23% annual change. These population estimates and projections come from the latest revision of the UN World Urbanization Prospects. These estimates represent the Urban agglomeration of Kalasin, which typically includes Kalasin's population in addition to adjacent suburban areas.
| City | 2026 Pop. ↓ | Growth |
|---|---|---|
| Bangkok | 11,543,900 | 1.34% |
| Chon Buri | 1,509,580 | 1.23% |
| Samut Prakan | 1,410,600 | 1.23% |
| Chiang Mai | 1,259,540 | 1.23% |
| Songkhla | 1,043,260 | 1.23% |
| Pathum Thani | 986,213 | 1.23% |
| Nakhon Ratchasima | 831,016 | 1.2% |
| Samut Sakhon | 624,139 | 1.23% |
| Udon Thani | 611,342 | 1.19% |
| Chiang Rai | 593,585 | 1.23% |
| Rayong | 580,833 | 1.23% |
| Nakhon Pathom | 576,756 | 1.65% |
| Surat Thani | 535,306 | 1.23% |
| Lop Buri | 535,183 | 2.11% |
| Ubon Ratchathani | 534,017 | 1.23% |
| Buri Ram | 489,735 | 1.23% |
| Lampang | 485,131 | 1.23% |
| Phra Nakhon Si Ayutthaya | 476,244 | 1.23% |
| Roi Et | 475,554 | 1.23% |
| Phuket | 466,495 | 1.23% |
| Ratchaburi | 444,864 | 1.35% |
| Chanthaburi | 412,898 | 1.65% |
| Sakon Nakhon | 411,309 | 1.23% |
| Suphan Buri | 386,646 | 1.65% |
| Lamphun | 342,337 | 1.23% |
