SUEZMAX is a naval architecture term for the largest ship measurements capable of transiting the Suez Canal, and is almost exclusively used in reference to tankers. Since the canal has no locks, the only serious limiting factors are draft (maximum depth below waterline), and height due to the Suez Canal Bridge. The current channel depth of the canal allows for a maximum of 20.1 m (66 ft) of draft, meaning a few fully laden supertankers are too deep to fit through, and either have to unload part of their cargo to other ships ("transhipment") or to a pipeline terminal before passing through, or alternatively avoid the Suez Canal and travel around Cape Agulhas instead. The canal has been deepened in 2009 from 18 to 20 m (60 to 66 ft).
The typical deadweight of a Suezmax ship is about 240,000 tons and typically has a beam (width) of 50 m (164.0 ft). Also of note is the maximum head room—"air draft"—limitation of 68 m (223.1 ft), resulting from the 70 m (230 ft) height above water of the Suez Canal Bridge. Suez Canal Authority produces tables of width and acceptable draft, which are subject to change. Currently the wetted surface cross sectional area of the ship is limited by 945 m2, which means 20.1 m (66 ft) of draught for ships with the beam no wider than 50.0 m (164.0 ft) or 12.2 m (40 ft) of draught for ships with maximum allowed beam of 77.5 m (254 ft 3 in).
Similar terms of Panamax, Malaccamax and Seawaymax are used for the largest ships capable of fitting through the Panama Canal, the Strait of Malacca and Saint Lawrence Seaway, respectively. Aframax tankers are those with a capacity of 80,000 metric tons deadweight (DWT) to 120,000 DWT. The term "capesize" refers to bulk carriers of size unable to traverse the Suez Canal and needing to go around the Cape of Good Hope but the recent deepening of the canal permits most ships of this class to traverse the canal. Future plans of deepening draft to 70 ft may lead to redefining of Suezmax specification as has happened in the case of Panamax specification consequent to plans to upgrade the Panama Canal.