Team selection for random battles is done according to several parameters. Each battle takes place in a so-called battle tier, and team balancing within this battle tier takes place according to vehicle specific weighting and additional restrictions. Player skill ratings are not taken into account for matchmaking, resulting in extreme skill mismatches between opposing teams, at times.
Battles can take place in eleven possible different battle tiers. Each vehicle, depending on its performance, is assigned a certain subset of these battle tiers that it is supposed to fight in.
The matchmaking chart shows which vehicle belongs to which battle tier. An English version can always be found here. It sometimes takes Wargaming a while to update it after patches, in this case you can refer to the Russian version, which is usually updated much faster.
The selection of the battle tier you fight in depends on the amount of players available for each battle tier and is otherwise random.
Players often confuse battle tiers and their vehicle's tier. The matchmaker does not try to match vehicles by vehicle tier. For example, a T-50 Light Tank is a tier 4 vehicle assigned to battle tiers 4-7, while the M3 Lee, which is also tier 4, is only assigned to battle tiers 4-6, this means that despite both vehicles being tier 4 tanks, the T-50 can potentially see tier 7 tanks in battle while the M3 Lee will only ever see vehicles as high as tier 6.
To see which battle tiers a vehicle can fight in, find it on the left side of the chart. If it is not listed as an exception on the Unique Matchmaking Chart, the default rules above apply. Take, for example, an MS-1. It doesn't have unique matchmaking. Thus we go find the row for Vehicle Tier 1, Light Tank, and see to the right that this vehicle can fight in battle tiers 1 and 2. Scrolling down, we see that nothing except tier 1 light tanks and medium tanks can fight in battle tier 1. For battle tier 2, we see that the MS-1 can meet tier 2 tank destroyers, SPGs (aka artillery), as well as light and medium tanks. The T2 Light Tank gets unique matchmaking, and we see that it's listed on the Unique Matchmaking Chart. While a typical tier 2 light tank will never encounter tier 4 tanks, the T2 Light Tank can, thanks to its unique matchmaking. The Pz.Kpfw. I, on the other hand, benefits from unique matchmaking, as it will never encounter tier 3 tanks. The applicable battle tiers for each vehicle are also shown on the right sidebar of each tank's page on this wiki.
Wargaming has announced that they are moving away from tanks with unique matchmaking. Many tanks that have unique matchmaking are being removed from sale, and it's unlikely any more tanks will be added to the chart in the future.
Once enough candidates for a certain battle tier are found, the matchmaker tries to form two teams from them. For this purpose each vehicle is assigned a certain weight, and the matchmaker tries to keep the weight of both teams as equal as possible. Weighting is performed by vehicle tier and vehicle type, some vehicles are individually weighted, and for some vehicles there are special restrictions.
Below are the rules for game version 0.8.0:
- Weight by Vehicle Tier is applied as follows:
- Tier 10: 100
- Tier 9: 60
- Tier 8: 40
- Tier 7: 27
- Tier 6: 18
- Tier 5: 12
- Tier 4: 8
- Tier 3: 5
- Tier 2: 3
- Tier 1: 2
- Weight by Vehicle Type is generally applied as follows:
- Individual Weights:
- M24 Chaffee is weighted like a tier 6 tank.
- The Pz.Kpfw. 38H 735 (f) "Hotchkiss" is a tier 2 tank with 233% extra weight, with 7 points it is weighted close to a tier 4 tank, but it is in the same battle tier as other tier 2 light tanks.
- The Comet is weighted like a heavy tank.
- The M4A3E2 Sherman Jumbo is weighted like a heavy tank.
- Special Restrictions
- The number of the same vehicle on opposing teams cannot differ by more than 1, except when the vehicles are in a platoon.
- Previously, the number of SPGs in opposing teams could never differ by more than 1. While this is still the goal for the match-maker, since update 0.7.4 it is not a strict restriction. Now, rarely, SPG numbers can differ by more, including one team having none while the other team has one or more.
- The total weight of the SPGs on opposing teams cannot differ by more than 25%.
- The total weight of the top tier vehicles on opposing teams cannot differ by more than 25%.
- It seems in general the weight of opposing teams does not differ by more than 10%, but it is unclear if there is a fixed limit.
- In the Version 8.5 update, a new Match Maker rule was planned for balancing Light Tanks. The rule was intended to balance out the number of Scout tanks on each team by balancing the weight of Scouts on both teams so they won’t differ by more than +/-20 vehicle weight points. The advantage to this rule is the matchmaker will no longer distribute a large number of scout tanks to one team and none to the other; the number of scouts should be roughly the same for each team. During tests, Scout balancing created other imbalances so it was not implemented. It is currently planned to be released with a later patch.
- The following vehicles are marked as Scouts:
- USSR: T-50, MT-25, LTTB, T54 ltwt.
- Germany: Pz.Kpfw. 38 (t) n.A., Pz.Kpfw. II Luchs, VK 16.02 Leopard, VK 28.01, Spähpanzer SP I C, Spähpanzer Ru 251
- United States: M5 Stuart, M24 Chaffee, T21, T37, T71, M41 Walker Bulldog, T49
- France: ELC AMX, AMX 12 t, AMX 13 75, AMX 13 90
- China: M5A1 Stuart, 59-16, WZ-131, WZ-132
Whether vehicles are stock or fully researched, how they are equipped, nor crew skill is taken into account by the match-maker.
Vehicle tier is not taken into consideration when balancing teams. This is a common misconception among players. For example, under the current rules a tier 8 medium can be matched against a tier 7 heavy tank. The only relevance of vehicle tier is to determine the battle tier.
However, the top tanks of each team have the same vehicle tier due to the current balancing rules.
IMPORTANT: If you are in a platoon, the entire platoon is placed into battles according to the platoon member in the vehicle with the highest battle tier. This can produce unwanted results in particular for new players at the lower tiers. For example, a tier 4 scout can enter battles up to tier 7, whereas a tier 4 medium tank on its own can only join battles up to tier 6. If these platoon together, the scout will pull the other tank up into its battle tier, where the other tank will usually be hopelessly outclassed. Please take this into account when forming platoons.
A special case of this is when you see a top tier tank platooned with one or two tier 1 tank. This is sometimes done on purpose. If you look above, a tier 10 heavy tank weighs 145 points, whereas a tier 1 tank weighs only 2. Thus the platoon's team a priori has a massive point deficit, which the match-maker will balance out by either dragging more lower tier tanks into the enemy team or by dragging more high tier tanks into the platoon's team. The tactic is frowned upon but permissible. It has become rare these days, likely because the success chances are mediocre. With two tier 1 tanks the team is missing 13.3% of its team that could play a useful role during the battle, whereas the only useful contribution the tier 1 tanks can make is sneak into the enemy cap.
The matchmaker does balance the number of tanks in platoons, but not the weight of the platooned tanks. This means one team can have 2 three-man-platoons with T8 tanks, whereas the other team has 3 two-man-platoons with T6 tanks. This rule may not apply, when the server is low populated.
- Map Restrictions by Battle Tier
Standard Battles in battle tiers 1 to 3 take place on a limited subset of the available maps only. This is done to allow new players to familiarize themselves with these smaller maps while they learn the basics of the game. Also except for Karelia, these are the smallest/most compact maps in the game, better suited for the very limited low tier tanks.
- Battle Tiers 1 and 2 fight on these maps:
- Province is limited to battle tiers 1 through 3.
- The map Widepark is limited to battle tiers 4 through 6.
All other battle tiers should get a random map distribution, but technical reasons relating to the allocation of server resources cause the three maps above to be the most commonly played maps for all tiers. For as yet unknown reasons also the distribution of other maps does not appear truly random. The frequency of newly introduced maps is slightly increased. See this forum thread for more details on actual map distribution in random battles.
Important note regarding camouflage skins: All (as of 9.2) of the maps listed for battle tiers 1-3 are summer maps. This means that tier 1 and 2 vehicles (see the Matchmaking Chart above for exceptions) will never see a desert map. So, for now at least, purchasing a desert camo skin for these vehicles is a complete waste, and a winter camo skin is minimal at best.
- Map Restrictions by Game Mode
- The following maps are not available in Random Battles:
- The game modes Assault and Encounter Battle take place on a limited subset of the available maps (follow the respective links for a list). In addition, Encounter battles are only available for players who have researched one or more tanks of Tier IV, and Assault battles are only available for players who have researched one or more tanks of Tier VI, unless in a platoon with a player who meets these requirements. However, you can have lower tier Encounter/Assault battles.