Panamax
Panama Canal — original 1914 locks
LOA 289.56 m · beam 32.31 m · draft 12.04 m
The gauge that named a ship type. Air draft 57.91 m under the Bridge of the Americas.
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Does it fit?
The famous ship sizes — Panamax, Suezmax and the rest — are just the dimensions of the world's great chokepoints. Pick any ship on this site and run it against all six gauges. The failing dimension is highlighted in red, straight from the published limits.
Gauge dimensions verified 2026-07-15 from: Panama Canal Authority · Suez Canal Authority · Marine Department Malaysia · St Lawrence Seaway Management Corporation · Vale — shipping. Published limiting dimensions for each gauge. Suez has no length limit and its beam limit trades against draft — the figures here are the maximum-draft case. Malaccamax is a depth constraint, not a canal rule.
The gauges
What each limit actually is
Neopanamax
Panama Canal — 2016 expansion locks
LOA 366 m · beam 51.25 m · draft 15.2 m
The expanded locks that reshaped world trade routes in 2016. Same 57.91 m air draft.
Suezmax
Suez Canal — fully laden transit
LOA no limit · beam 50 m · draft 20.1 m
No length limit; beam trades against draft (up to 77.5 m at reduced draft — the megamax container ships transit this way). Figures shown are the maximum-draft case. Air draft 68 m.
Malaccamax
Strait of Malacca — depth of the Asia–Europe shortcut
LOA no limit · beam no limit · draft 25 m
A geographic depth limit of roughly 25 m, not a rulebook. The half-million-tonne ULCCs failed it and detoured via Lombok.
Seawaymax
St Lawrence Seaway locks
LOA 225.6 m · beam 23.77 m · draft 8.08 m
The small gauge that shapes every Great Lakes ship. Air draft 35.5 m.
Chinamax
Chinese ore-terminal standard
LOA 360 m · beam 65 m · draft 24 m
A port standard rather than a waterway — the envelope the 400,000 t Valemax fleet was designed to fill exactly.
Deeper reading: Panamax, Neopanamax and Suezmax, explained · LOA, beam and draft — what the three dimensions mean