504: 80 hp (60 kW) Gnome Lambda engine.

Original model
504A:
Modified with smaller ailerons and broader struts.
80 hp (60 kW) Gnome engine.

504B
Version for RNAS with larger fin.
80 hp (60 kW) Gnome or Le Rhône engine.

504C
Single-seat anti-zeppelin aircraft for the RNAS.
The 504C was fitted with an extra fuel tank, in place of the observer.

504D
Single-seat anti-zeppelin aircraft for the Royal Flying Corps.
Six built.

504E: 100 hp (75 kW) Gnome Monosoupape engine.
Ten built.

504F: 75 hp (56 kW) Rolls-Royce Hawk engine.
One built.

504G: 80 hp (60 kW) Gnome engine.

504H
Used for catapult trials.
80 hp (60 kW) Gnome engine.

504J
Used as a trainer.
100 hp (75 kW) Gnome or 80 hp (60 kW) Le Rhône engine.

504K
Two-seat training aircraft.
The 504K had a universal mount to take different engines.
Single-seat fighter (Comic) conversion used for anti-zeppelin work.
Several were assembled in Australia by Australian Aircraft & Engineering.
130 hp (97 kW) Clerget 9B, 100 hp (75 kW) Gnome Monosoupape or 110 hp (82 kW) Le Rhône 9J engines.

504K Mk.
II
Hybrid trainer based on 504K fuselage with 504N undercarriage and wings and powered by rotary engine.
Built under licence in Mexico as Avro Anahuac.

504L
Floatplane version.
150 hp (110 kW) Bentley BR1, 130 hp (97 kW) Clerget or 110 hp (82 kW) Le Rhône engines.

504M
Three-seat cabin biplane.
Only one was ever built.
100 hp (75 kW) Gnome engine.

504N
Two-seat training aircraft.
Redesigned postwar trainer for RAF with 160 hp (120 kW) Armstrong Siddeley Lynx engine.
598 built.

504O
Floatplane version of 504N. First aircraft to fly above the Arctic Circle in 1923 Oxford Expedition.

504P
Unbuilt version of the 504N with side-by-side seating.

504Q
Three-seat cabin biplane.
The 504Q was built for the Oxford University Arctic Expedition.
Only one was ever built, powered by an Armstrong Siddeley Lynx engine.

504R Gosport
Reworked trainer with revised, lightweight structure.
Five prototypes flown 1926 to 1927 with various engines (100 hp/75 kW Gnome Monosoupape, 100 hp/75 kW) Avro Alpha, (140 hp/104 kW) Armstrong Siddeley Genet Major and (150 hp/110 kW) Armstrong Siddeley Mongoose), with the Mongoose chosen for production aircraft.
Ten were sold to Argentina, with 100 more built by FMA under licence in Argentina.
Twelve were exported to Estonia, remaining in service until 1940, and an unknown number to Peru.

504S
Two-seat training aircraft.
Built under licence in Japan by Nakajima.

Yokosuka K2Y1
Japanese version of the Avro 504N, given the long designation Yokosuka Navy Type 3 Primary Trainer, powered by a 130 hp (97 kW) Mitsubishi-built Armstrong Siddeley Mongoose radial piston engine, 104 built.

Yokosuka K2Y2
Improved version of the K2Y1, powered by a 160 hp (120 kW) Gasuden Jimpu 2 radial piston engine.
360 built (K2Y1 and K2Y2).
Watanabe built aircraft were given the long designation Watanabe Navy Type 3-2 Land-based Primary Trainer.

U-1 (Uchebnyi - 1) Avrushka
Russian copy of the 504K. Over 700 built.

MU-1 (Morskoy Uchebnyi - 1)
Russian seaplane version.

Orlogsværftet Flyvemaskineværksted LB.I - Danish production at the Royal Naval Dockyard (Orlogsværftet)
504: 80 hp (60 kW) Gnome Lambda engine.
Original model
504A:
Modified with smaller ailerons and broader struts. 80 hp (60 kW) Gnome engine.
504B
Version for RNAS with larger fin. 80 hp (60 kW) Gnome or Le Rhône engine.
504C
Single-seat anti-zeppelin aircraft for the RNAS. The 504C was fitted with an extra fuel tank, in place of the observer.
504D
Single-seat anti-zeppelin aircraft for the Royal Flying Corps. Six built.
504E: 100 hp (75 kW) Gnome Monosoupape engine. Ten built.
504F: 75 hp (56 kW) Rolls-Royce Hawk engine. One built.
504G: 80 hp (60 kW) Gnome engine.
504H
Used for catapult trials. 80 hp (60 kW) Gnome engine.
504J
Used as a trainer. 100 hp (75 kW) Gnome or 80 hp (60 kW) Le Rhône engine.
504K
Two-seat training aircraft. The 504K had a universal mount to take different engines. Single-seat fighter (Comic) conversion used for anti-zeppelin work. Several were assembled in Australia by Australian Aircraft & Engineering. 130 hp (97 kW) Clerget 9B, 100 hp (75 kW) Gnome Monosoupape or 110 hp (82 kW) Le Rhône 9J engines.
504K Mk.II
Hybrid trainer based on 504K fuselage with 504N undercarriage and wings and powered by rotary engine. Built under licence in Mexico as Avro Anahuac.
504L
Floatplane version. 150 hp (110 kW) Bentley BR1, 130 hp (97 kW) Clerget or 110 hp (82 kW) Le Rhône engines.
504M
Three-seat cabin biplane. Only one was ever built. 100 hp (75 kW) Gnome engine.
504N
Two-seat training aircraft. Redesigned postwar trainer for RAF with 160 hp (120 kW) Armstrong Siddeley Lynx engine. 598 built.
504O
Floatplane version of 504N. First aircraft to fly above the Arctic Circle in 1923 Oxford Expedition.
504P
Unbuilt version of the 504N with side-by-side seating.
504Q
Three-seat cabin biplane. The 504Q was built for the Oxford University Arctic Expedition. Only one was ever built, powered by an Armstrong Siddeley Lynx engine.
504R Gosport
Reworked trainer with revised, lightweight structure. Five prototypes flown 1926 to 1927 with various engines (100 hp/75 kW Gnome Monosoupape, 100 hp/75 kW) Avro Alpha, (140 hp/104 kW) Armstrong Siddeley Genet Major and (150 hp/110 kW) Armstrong Siddeley Mongoose), with the Mongoose chosen for production aircraft. Ten were sold to Argentina, with 100 more built by FMA under licence in Argentina. Twelve were exported to Estonia, remaining in service until 1940, and an unknown number to Peru.
504S
Two-seat training aircraft. Built under licence in Japan by Nakajima.
Yokosuka K2Y1
Japanese version of the Avro 504N, given the long designation Yokosuka Navy Type 3 Primary Trainer, powered by a 130 hp (97 kW) Mitsubishi-built Armstrong Siddeley Mongoose radial piston engine, 104 built.
Yokosuka K2Y2
Improved version of the K2Y1, powered by a 160 hp (120 kW) Gasuden Jimpu 2 radial piston engine. 360 built (K2Y1 and K2Y2). Watanabe built aircraft were given the long designation Watanabe Navy Type 3-2 Land-based Primary Trainer.
U-1 (Uchebnyi - 1) Avrushka
Russian copy of the 504K. Over 700 built.
MU-1 (Morskoy Uchebnyi - 1)
Russian seaplane version.
Orlogsværftet Flyvemaskineværksted LB.I - Danish production at the Royal Naval Dockyard (Orlogsværftet)
Avro 504