Armor Steel
Areal Densities

References Consulted:
US Battleships: An Illustrated Design History by Norman Friedman
Japanese Cruisers of the Pacific War

Weight per Square Foot
(pounds per square ft)

Thickness of Plate

10 psf

0.25” (6.35mm)

15 psf

0.375” (9.52mm)

20 psf

0.5” (12.7mm)

25 psf

0.625” (15.88mm)

30 psf

0.75” (19.05mm)

35 psf

0.875” (22.23mm)

40 psf

1” (25.40mm)

50 psf

1.25” (31.75mm)

60 psf

1.5” (38.1mm)

70 psf

1.75” (44.45mm)

80 psf

2” (50.8mm)

90 psf

2.25” (57.15mm)

100 psf

2.5” (63.5mm)

120 psf

3” (76.2mm)

140 psf

3.5” (88.9mm)