Impero was 240.68 meters (789.6 ft) long overall and had a beam of 32.82 m (107.7 ft) and a draft of 9.6 m (31 ft).
She was designed with a standard displacement of 40,992 long tons (41,650 t), a violation of the 35,000-long-ton (36,000 t) restriction of the Washington Naval Treaty; at full combat loading, she displaced 45,485 long tons (46,215 t).
The ship was to be powered by four Belluzo geared steam turbines rated at 128,000 shaft horsepower (95,000 kW).
Steam was provided by eight oil-fired Yarrow boilers.
The engines provided a top speed of 30 knots (56 km/h; 35 mph) and a range of 3,920 mi (6,310 km; 3,410 nmi) at 20 kn (37 km/h; 23 mph).
Impero would have had a crew of 1,830 to 1,950 if she had been completed.

Impero's main armament would have consisted of nine 381-millimeter (15.0 in) 50-caliber Model 1934 guns in three triple turrets; two turrets were placed forward in a superfiring arrangement and the third was located aft.
Her secondary anti-surface armament would have consisted of twelve 152 mm (6.0 in) 55-caliber Model 1934/35 guns in four triple turrets amidships.
These were to be supplemented by four 120 mm (4.7 in) 40-caliber Model 1891/92 guns in single mounts; these guns were old weapons and were primarily intended to fire star shells.
Impero was intended to be equipped with an anti-aircraft battery that comprised twelve 90 mm (3.5 in) 50-caliber Model 1938 guns in single mounts, twenty 37 mm (1.5 in) 54-caliber guns in eight twin and four single mounts, and sixteen 20 mm (0.79 in) 65-caliber guns in eight twin mounts.

The ship was protected by a main armored belt that was 280 mm (11 in) with a second layer of steel that was 70 mm (2.8 in) thick.
The main deck was 162 mm (6.4 in) thick in the central area of the ship and reduced to 45 mm (1.8 in) in less critical areas.
The main battery turrets were 350 mm (14 in) thick and the lower turret structure was housed in barbettes that were also 350 mm thick.
The secondary turrets had 280 mm thick faces and the conning tower had 260 mm (10 in) thick sides.
Impero was to be fitted with a catapult on her stern and equipped with three IMAM Ro.43 reconnaissance float planes or Reggiane Re.2000 fighters.
Impero was 240.68 meters (789.6 ft) long overall and had a beam of 32.82 m (107.7 ft) and a draft of 9.6 m (31 ft). She was designed with a standard displacement of 40,992 long tons (41,650 t), a violation of the 35,000-long-ton (36,000 t) restriction of the Washington Naval Treaty; at full combat loading, she displaced 45,485 long tons (46,215 t). The ship was to be powered by four Belluzo geared steam turbines rated at 128,000 shaft horsepower (95,000 kW). Steam was provided by eight oil-fired Yarrow boilers. The engines provided a top speed of 30 knots (56 km/h; 35 mph) and a range of 3,920 mi (6,310 km; 3,410 nmi) at 20 kn (37 km/h; 23 mph). Impero would have had a crew of 1,830 to 1,950 if she had been completed.
Impero's main armament would have consisted of nine 381-millimeter (15.0 in) 50-caliber Model 1934 guns in three triple turrets; two turrets were placed forward in a superfiring arrangement and the third was located aft. Her secondary anti-surface armament would have consisted of twelve 152 mm (6.0 in) 55-caliber Model 1934/35 guns in four triple turrets amidships. These were to be supplemented by four 120 mm (4.7 in) 40-caliber Model 1891/92 guns in single mounts; these guns were old weapons and were primarily intended to fire star shells. Impero was intended to be equipped with an anti-aircraft battery that comprised twelve 90 mm (3.5 in) 50-caliber Model 1938 guns in single mounts, twenty 37 mm (1.5 in) 54-caliber guns in eight twin and four single mounts, and sixteen 20 mm (0.79 in) 65-caliber guns in eight twin mounts.
The ship was protected by a main armored belt that was 280 mm (11 in) with a second layer of steel that was 70 mm (2.8 in) thick. The main deck was 162 mm (6.4 in) thick in the central area of the ship and reduced to 45 mm (1.8 in) in less critical areas. The main battery turrets were 350 mm (14 in) thick and the lower turret structure was housed in barbettes that were also 350 mm thick. The secondary turrets had 280 mm thick faces and the conning tower had 260 mm (10 in) thick sides. Impero was to be fitted with a catapult on her stern and equipped with three IMAM Ro.43 reconnaissance float planes or Reggiane Re.2000 fighters.
Italian battleship Impero