Alright, on to the pressing question: How are levels calculated?

Halo 2's stats system is actually pretty simple. When you win a game in a ranked matchmaking playlist you earn experience points. When you lose a game in a ranked matchmaking playlist you lose experience points. Your total experience points determine your level. Simple.

Well, alright, there are few things that complicate this system. If you only ever played the Head to Head playlist against one other player this would make sense. But Halo 2 supports games with up to 16 players. And team games. And games with up to 16 players and 8 teams! How does that work, huh!?

Alright, alright, don't get antsy. It really is a simple system. Let me explain. For discussion purposes it's useful to think of a free-for-all game as a game where every player is his own team.

First off, the only thing that matters for experience and level calculations is your current experience points and your team's final standing, your place at the end of the game. It doesn't matter how you got there, and it doesn't matter whether you were the one that planted the flag or that got the most kills on your team. All that matters is the end result that your team achieved. Let's say JoeBoy, Sly, SueMe, and Ralf all play a game with the following results:

Halo 2 will calculate experience gained or lost first for Sly vs. JoeBoy, then for Sly vs. SueMe, then for Ralf, then total it all up and divide by 3. The result is Sly's change in experience points, in this case positive. In SueMe's case the game will calculate vs. the other three and divide by three. This means that SueMe gains points for beating Ralf but loses points for getting beat by Sly and JoeBoy. SueMe's final experience point change will be negative, but not as bad as Ralf's will be, as she earned something for beating him.

This same concept applies to teams. Experience change for a member of a team is calculated vs. every other member of every other team, then averaged.

Alright, on to Levels. Your level is nothing more than an abstraction of your experience. All new players start at level 1. There are 50 levels total. Which level your experience corresponds to is determined by the following chart.

Experience Calculations



We know, this is all just a bunch of mumbo jumbo. And that stuff about the player being like the team is just confusing. And without knowing how many experience points are up for grabs in a game none of this really has any meaning. Hang in there.

You may have heard the term "ELO" bantered about in reference to Halo 2. ELO is a statistical system for calculating skills developed by Arpad Elo to track chess rankings. Our system is similar to ELO in that experience changes are based solely on the game's final outcome. In addition, the resulting points gained or lost are not fixed. Instead point changes are determined by comparing the winner's skill to the loser's skill. You don't really need to know much more about the system to understand how Halo 2 experience works. Basically, when we calculate experience point change at the end of a game we consult the following chart.

Experience Exchange by Level Difference

Level Diff Higher Win Higher Loss Lower Win Lower Loss 0 100 100 100 100 1 92 108 108 92 2 85 115 115 85 3 79 121 121 79 4 74 126 126 74 5 70 130 130 70 6 66 134 134 66 7 63 137 137 63 8 60 140 140 60 9 58 142 142 58 10 56 144 144 56 11 54 146 146 54 12 53 147 147 53 13 52 148 148 52 14 51 149 149 51 15+ 50 150 150 50

Let's go back to our previous example for a minute and assign these players levels:

1st Place: Sly (Level 10)

2nd Place: JoeBoy (Level 7)

3rd Place: SueMe (Level 8)

4th Place: Ralf (Level 5)

First we'll calculate experience change for Sly. Sly (level 10) beat JoeBoy (level 7). They're 3 levels apart, so we consult the 4th row down in the above chart to learn that Sly, the higher level player, gains 79 points. Sly also beat SueMe (8), but this time because SueMe is closer in level earning 85 points. Finally Sly picked up just 70 points from Ralf (5) because Ralf is so much lower level. Adding these all up we see that Sly earned a total of 234 points (79 + 85 + 70). We divide this by 3 to get Sly's final experience point change, +78.

Now let's see how JoeBoy fared. He lost to Sly, who was higher level. Again consulting row 4 of the table we look at the Lower Loss column to learn that JoeBoy lost 79 points. However, he also won against SueMe, who also happened to be a level higher. Row 2 of the chart shows us that a lower win earns 108 points. Finally, JoeBoy also picked up 85 experience points for beating Ralf. (Remember, Sly only got 70 for beating Ralf because their levels were further apart.) So JoeBoy earned a total of +38 experience points ((-79 + 108 + 85)/3) for his 2nd place finish.

Performing a similar calculation we see that SueMe lost 38 experience points ((-85 - 108 + 79)/3) and Ralf lost 78 experience points ((-70 - 85 - 79)/3).

Simple, see? Well, sort of. The above calculations hold up when all players are level 15 and above, but an extra consideration is made at lower levels. We give all low-level players a helping hand by reducing their point loss. Please consult the chart below.

Level Loss Factor 1 0.00% 2 2.50% 3 5.00% 4 7.50% 5 10.00% 6 15.00% 7 20.00% 8 27.50% 9 35.00% 10 40.00% 11 45.00% 10 50.00% 11 55.00% 12 57.50% 13 60.00% 14 62.50% 15 65.00% 16 67.50% 17 70.00% 18 72.50% 19 75.00% 20 77.50% 21 80.00% 22 82.50% 23 85.00% 24 87.50% 25 90.00% 26 92.50% 27 95.00% 28 97.50% 29+ 100.00%

This chart indicates a factor that we scale down point loss by. Remember the example above? JoeBoy gained points overall, but lost 79 to Sly. JoeBoy is level 7, so we multiply the 79 points lost by 0.2, resulting in just 15 points lost, making his new total +59 experience gained ((-15 + 108 + 85)/3) instead of his original +38.

SueMe lost 38 experience points according to the above calculations. If we use the loss factor for a player at level 8, however (0.275), this value changes. SueMe's loss to Sly originally cost her 85 points, and her loss to JoeBoy cost her 108 points. We multiply 85 by 0.275 to get a new loss of 23 points vs. Sly, and 108 by 0.275 to get a new loss of 29 points vs. JoeBoy. SueMe's new total experience change is +9 ((-23 - 29 + 79)/3) instead of the original -38. Quite a difference!

Ralf lost to everyone, but he's just level 5 and much lower level than his opponents. 78 points lost is pretty severe. Instead when we apply a loss factor of 0.1 we see that Ralf lost just 7 experience points ((-7 - 8.5 - 7.9)/3) instead of -78, far less experience that he would have lost against a single opponent at his same level.

The final results of this game: Sly +78, JoeBoy +59, SueMe +9, and Ralf -7

If these players had all been 26 levels higher but retained the same level differentials the results would have been the original Sly +78, JoeBoy +38, SueMe -38, and Ralf -78, a net sum of zero. Between levels 30 and 40 the Halo 2 experience system is zero sum. Below level 31 it is obviously not zero sum (the above game resulted in a net +139 experience points added to the system) and therefore, in order to keep the system balanced, when you exceed level 40 your positive experience gain is scaled by the following factor to compensate:

Level Win Factor 1-41 100% 42 95% 43 90% 44 85% 45 80% 46 70% 47 65% 48 60% 49 55% 50 50%

Special Considerations

