Tiering FAQ

Q: What are the tiers?

The official tiers are Ubers, OverUsed (OU), UnderUsed (UU), RarelyUsed (RU), NeverUsed (NU), and PU. There are also several banlists, which are UnderUsed Borderline, RarelyUsed Borderline, NeverUsed Borderline, PU Borderline; these lists are often just referred to by their initials: UUBL, RUBL, NUBL, and PUBL. The banlists are meant to only serve as lists of Pokémon that are too powerful for their respective tiers.

Q: What is the purpose of tiers?

Tiers provide a snapshot of what the most important threats in the metagame are. While any Pokémon can be viable in a higher tier, tiers show you what Pokémon are most commonly used in the metagame that you are looking at. This is extremely helpful when teambuilding to make sure you account for the right threats. There is no use preparing for Musharna when you're playing OU, because you will rarely, if ever, see one!

Tiers also serve another important role: they allow for many metagames to exist in order to make all Pokémon viable. For example, that Musharna is probably never seen in OU because it is simply outclassed by too many Pokémon. There is, however, a place where it can excel: NU! Many interesting Pokémon that cannot make it in OU often excel in lower tiers; Pokémon such as Escavalier, Kabutops, and Musharna can all find useful niches there!

Q: Am I forced to use Smogon's tiers?

We only enforce our tiers in our official tournaments, on our ladders, and in Wi-Fi battles that are arranged on Smogon. You may follow whatever tiers you like anywhere else, which includes direct challenges on Pokémon Showdown. In that case, as long as both parties agree, you may use whatever rules you want.

Q: Who uses your tiers?

The primary audience for our tiers and rules are people who play Pokémon competitively and want to play in a 6v6 singles format under rules that both players know and understand. They are not intended to replace Nintendo's VGC format, nor is the ruleset meant to control how someone chooses to play the game's story. They are simply rules that have evolved over time based in a competitive mindset for competitive players.

Q: How are tiers and banlists determined?

Smogon uses usage as the main metric to determine tiers, which is evident by the full names of the tiers: OverUsed, UnderUsed, RarelyUsed, NeverUsed, and PU. The banlists UUBL, RUBL, NUBL, and PUBL serve to balance out the usage-based tiers. Ubers serves as the banlist for OU, but it is also considered an official Smogon tier.

Each successive tier is calculated off of the higher tier as follows:

Tiers are recalculated every three months using weighted usage statistics. The most recent month is given the greatest weight, with the two months prior being given increasingly lower importance. The aggregate usages of all Pokémon are listed, and any Pokémon that fall above the cutoff of 3.406% are counted in that tier. For example, when looking at OU's statistics, everything below the 3.406% cutoff is UU. From UU's, everything below is RU, and everything below RU's cutoff is listed as NU.

While that number looks like it was just pulled out of thin air, it is not quite that arbitrary. Any Pokémon whose usage is above the cutoff had more than a 50% chance to be seen at least once in 20 battles on the given ladder. For example, if you play 20 battles on the UU ladder on a simulator, while it is not guaranteed that you will see every Pokémon that is UU, these are generally the Pokémon that you will be fighting. For this reason, it is helpful to see tiers essentially as threatlists when you're building teams.

Q: Why is usage a good metric for tiering? Why not use something like winrate?

Generally, we assume that most people who play competitive Pokémon play to win, and when people play to win, they generally use what is best. That said, usage is the most objective form of tiering for Pokémon. For example, because Pokémon is not played one-on-one, winrate is not an accurate measure; while support Pokémon such as Ferrothorn and Blissey might lose to most Pokémon one-on-one, they are still an important part of a team's structure.

Other objective metrics might include BST or legendary status, both of which are often misleading because a Pokémon is more than just the sum of its stats or an arbritrary recognition as a legendary Pokémon. While some low-BST Pokémon such as Talonflame and Breloom excel thanks to well-placed stats, a good movepool, and a useful ability, others, such as Regigigas, Articuno, and Mesprit, fall short because of a bad distribution of stats, a poor typing, or a useless or detrimental ability.

Q: What is the process of banning a Pokémon?

Sometimes, when a Pokémon seems too strong for the tier, it is labelled as what we call a suspect. Once suspects are named, they can be tested in isolation in what is known as a suspect test. These tests, which last either two or three weeks depending on the suspect, allow voters to decide whether or not that Pokémon truly was overcentralizing or not.

People can obtain eligibility to vote by playing in the suspect test, making sure their rating in that test falls above a certain point and that they've played in enough games. This is to ensure that voters are informed so that they can make an educated vote. Once the test is over, voting takes place in a blind vote, so there is no risk of bandwagoning or one person's opinions shaping another's.

Q: Can Pokémon be unbanned?

Yes. Pokémon bans are not permanent. If there are significant shifts in the metagame due to new Pokémon being released, new moves for old Pokémon being added, or new hidden abilities becoming available, banned Pokémon can be re-introduced to the metagame via a second suspect test. Unbannings occur much in the same way as bannings, only the suspect ladder includes an extra Pokémon, the suspect, rather than the normal suspect test, which has all Pokémon except for the suspect.

A prominent example of this is in Generation V NeverUsed, where Jynx was banned early in the metagame but was unbanned after several Pokémon dropped from RU and BW2 changes had taken effect. A similar situation occured in BW when Latios, for the first time, dropped down from Ubers into OU, where it was seen that, without Soul Dew, it was not quite as powerful as people initally expected.

Q: Why did you ban X Pokémon?

More information about past bans can be found on the forums. As a general rule, however, Pokémon are banned when they become too overcentralizing. This is not to say that they don't have counters, but rather that everyone either runs that Pokémon or runs its counters, which, in the case of some suspects, are often obscure Pokémon that normally would not see the light of day.

For example, in XY, Mega Kangaskhan was considered so powerful that people used obscure, highly specialized counters that would otherwise be outclassed and more or less useless in battle, such as Sableye.

Q: X Pokémon is strong! Why isn't it Ubers?

Our tiering is based on aggregate usage over three-month spans. Every three months, our tiers are "refreshed", so to speak, and Pokémon rise and drop based on their usage for the past three months. With this in mind, there are many Pokémon that can and do work in tiers higher than the tier they are listed under. The reason it isn't OU, or any other tier for that matter, is simply because it didn't obtain enough usage. It says nothing about the power of the Pokémon in question, but realize that people generally tend to use Pokémon that work and are easy to use. Lower tier Pokémon can perform very well in higher tiers but often require specialized team support. In those cases, there will be analyses detailing the best strategy to use for the lower tier Pokémon.

Q: Can I use lower tier Pokémon in higher tiers?

As alluded to in the previous answer, yes, of course! You may not use a Pokémon in a tier lower than the one it is officially listed in, but you can certainly use a Pokémon in a tier higher than the one it is listed in. For reference, the order of tiers from highest to lowest is: Ubers, OverUsed (OU), UnderUsed (UU), RarelyUsed (RU), and NeverUsed (NU). Smogon Doubles and Little Cup are tiered independently of these metagames, and VGC is not tiered at all, instead using the current rules for that particular season.

Q: Are there tiers for the likes of LC and Doubles?

Tiers for Little Cup and Doubles are entirely separate from the main level 100 single battle tiers that include Ubers, OU, and the lower tiers. Pokémon that are banned in either Doubles or Little Cup are not automatically banned in Singles, nor vice versa. The reason for this is simple: Little Cup and Doubles are entirely different playstyles from the normal tiers. Little Cup is played at level 5, which means that stats don't have as much of a range as they would at level 100. Two Pokémon could have different base Speed stats but still Speed tie in Little Cup. Doubles is, well, two-on-two, which means a whole host of other strategies and moves become viable.

Q: Well, which tier should I play?

This is the beauty of the tiering system: you can play whichever tier you want to! Whether you enjoy the subtle strategy involved behind battling with NU Pokémon or the brutal action of Ubers, there is probably a tier for you! Even if none of the standard tiers gets you your kicks, Smogon also has an Other Metagames forum where people can play with even weirder rulesets.