What is the biggest nuclear bomb today?

What is the biggest nuclear bomb today?
With its retirement, the largest bomb currently in service in the U.S. nuclear arsenal is the B83, with a maximum yield of 1.2 megatons.B53 nuclear bomb.

B53

Mass
8,850 lb (4,010 kg)

Length
12 ft 4 in (3.76 m)

Diameter
50 in (4.2 ft; 1.3 m)

Filling
Fission: 100% oralloy Fusion: Lithium-6 deuteride

With its retirement, the largest bomb currently in service in the U.S. nuclear arsenal is the B83, with a maximum yield of 1.2 megatons.

B53 nuclear bomb.

B53
Mass 8,850 lb (4,010 kg)
Length 12 ft 4 in (3.76 m)
Diameter 50 in (4.2 ft; 1.3 m)
Filling Fission: 100% oralloy Fusion: Lithium-6 deuteride