| Călmăţui River | |
| River | |
| Countries | Romania |
|---|---|
| Counties | Buzău County, Brăila County |
| Tributaries | |
| - left | Negreasca, Ruşavăţ, Batogu |
| - right | Strâmbeanu, Puturosu |
| Towns | Smeeni, Însurăţei |
| Source | |
| - location | South of Buzău |
| Mouth | Danube |
| - location | Berteştii de Jos |
| - coordinates | |
| Length | 145 km (90 mi) |
| Basin | 820 km2 (317 sq mi) |
The Călmăţui River is a tributary of the Danube in Romania. Its source is a few km southwest of Buzău. It flows generally eastwards and flows into the Danube at Berteştii de Jos.