Classification societies by classed tonnage
IACS membership requires meeting a defined technical and regulatory standard; the 11 societies between them class essentially the world commercial fleet. The largest four (DNV, ABS, Bureau Veritas, ClassNK) handle the bulk of tankers, container, gas, and large bulk; the regional members (Korean Register, Russian Maritime Register-style, Polish Register) handle their national flag plus an export book.
| # | Name | Classed GT | Notes |
|---|---|---|---|
| 1 | DNV | ~290 M GT | DNV |
| 2 | Nippon Kaiji Kyokai (ClassNK) | ~280 M GT | ClassNK |
| 3 | American Bureau of Shipping | ~270 M GT | ABS |
| 4 | China Classification Society | ~250 M GT | CCS |
| 5 | Bureau Veritas | ~145 M GT | BV |
| 6 | Lloyd's Register | ~130 M GT | LR |
| 7 | Korean Register | ~80 M GT | KR |
| 8 | Registro Italiano Navale | ~50 M GT | RINA |
| 9 | Indian Register of Shipping | ~14 M GT | IRS |
| 10 | Polish Register of Shipping | ~4 M GT | PRS |
| 11 | Croatian Register of Shipping | ~2.5 M GT | CRS |
Data sourced from the seafarerindex datasets — see /sources for methodology. Rankings update each time the underlying data is refreshed.