How are the Armor value multipliers / modifiers calculated

How are the armor multipliers calculated? Is there some complex way to get it or is it more of an educated guess?

Types of armour in-game

  • KE: Kinetic Energy
  • CE: Chemical Energy

Armour modifier applies to both types of penetrators, unless specified.

Material or Component Armour Modifier Examples
Ground vehicles Ground vehicles Ground vehicles
Rolled homogeneous armour (RHA) x1.00
Modern RHA x1.01 Leopard 1A5 · Chieftain Mk 3
Cast homogeneous armour (CHA) x0.94
Modern CHA x0.98 KPz-70 · T-64B
High hardness rolled armour (HHRA) x1.25 Pz.III L · Ikv 91
Modern HHRA x1.10 Strv 122A · BMP-2
Tracks x0.75
Structural steel x0.45 T26E1-1
Structural steel of chassis x0.60
Wheel x0.30
Rubber-fabric screens x0.20 OF-40 · M901
Composite screen x0.16 KE; x2.00 CE Leclerc S2 · Type 16
Air (Spaced armour) x0.05 KE; x0.30 CE AMX-32 · KPz-70
Aluminium x0.20 ST-A1 · BMP-2M
Aluminium alloy 5083 x0.32 CM25 · M3 Bradley
Aluminium alloy AA7017 x0.50 Striker · Stormer HVM
Aluminium alloy 7020 x0.50 Centauro I 120
Aluminium alloy 7039 x0.50 R3 T20 FA-HS · Type 75 SPH
Alloy ABT-101 x0.38 BMP-2 · Object 685
Alloy ABT-102 x0.42 BMP-3
Aluminium alloy AMS 4050A x0.50 AMX-10RC · Type 87
Alloy BT-6 x0.70 T-80U
External composite armour with NERA elements x0.10 KE; x1.70 CE Leopard 2A6 · Type 90 (B)
Wood x0.05 IS-3 · Object 120
MEXAS 2 x0.16 M1128
MEXAS 2C x0.16 M1128
Naval vessels Naval vessels Naval vessels
Rolled homogeneous armour x1.00
Rolled cemented armour x1.10 Heavy cruisers, battleships
Structural steel x0.45
Coal bunker x0.01
Concrete x0.35 AF D1 · AF D3
Wood x0.05 KE; x0.00 CE
Antifragmentation armour x0.90
Hardened armour x0.80