Team Fortress 2 leads as biggest player counts on Steam revealed

A study into the number of players that own the most popular games on Steam has revealed Team Fortress 2 has a userbase of more than 50 million players.

The figures were calculated by Ars Technica using a method laid out by The End Is Nigh developer Tyler Glaiel, although Valve has already blocked this system for calculating audience numbers.

Glaiel's method centres around Steam Achievements, using the percentage of players that have unlocked each one to calculate the number of copies a game has sold. In the example given, an achievement earned by 0.012782207690179348 per cent of players translates to eight players out of 62,587.

Ars Technica has used this theory to calculate the userbases for all titles with achievements, although note that this only covers 13,000 of the titles currently available on Steam. Titles that do not feature achievements - with a notable example being the hugely popular Dota 2 - are therefore missing from the ranking below.

It's also important to note this does not separate users who added a title to their Steam Library and never played it, nor does it differentiate between purchases and free or discounted downloads. Nevertheless, it's an interesting insight into some of the audiences developers are catering to on Steam.

You can check out a hefty list at their site, but we've included the Top Ten below. In terms of the titles that rank highly, there are few surprises; half of them are Valve games and almost all are multiplayer-centric.

What is interesting is the gaps between titles in terms of player count - often at least one million users apart, with CS:GO roughly 10 million sales ahead of PlayerUnknown's Battlegrounds (although that's still a remarkable accomplishment for PUBG, given that it's not only just coming up on 18 months old).

As mentioned, the method for calculating these figures is no longer available but as these are generated using Steam's own API, they are believed to be even more accurate than those previously gathered by SteamSpy. Valve has recently revealed it is working on its own solution for calculating sales figures, promising it will be "better" than previous developer-conceived methods.

You can check out the Top 10 below:

1. Team Fortress 2 (50,191,347)
2. Counter-Strike: Global Offensive (46,305,966)
3. PlayerUnknown's Battlegrounds (36,604,134)
4. Unturned (27,381,399)
5. Left For Dead 2 (23,143,723)
6. Payday 2 (18,643,807)
7. Garry's Mod (18,576,379)
8. Warframe (16,332,217)
9. Counter-Strike: Source (15,001,876)
10. Paladins (14,371,946)