Levels are a game mechanic in Diep.io. Players level up by gaining score, killing other players, destroying Polygons and Crashers, or through passive XP gain (in the case of the game mode, Survival). The player's total score and level are represented by two bars below their name, as shown on the right. The numbers on the top bar represent the player's total score whilst comparing the player's score as a percentage of the score of the Leader (the player at the top of the Scoreboard)  as such, when the player is the leader, this bar is full. Another difference between these two bars is that the score bar can fluctuate up and down, while the level bar can only increase. The bottom bar represents the player's current level and their current progress to the next level; once this bar is full, they gain a level. This system terminates at level 45, as no higher levels can be reached.
Mechanics
For every level gained, up to Level 28, a skill point is received (after which a skill point is received at Level 30, and then every 3 levels afterward up to level 45). Skill points are used to upgrade the player's Stats. In the skill tree, shown to the right, up to 7 total skillpoints may be invested into a stat, with there being eight stats. Four stats can be maxed out (or filled), with another receiving the last five points. An exception to this is the Smasher branch, which can use up to 10 points, but only 4 stats. The Auto Smasher, however, has all 8 stats with a maximum of 10 points. There is a maximum of 33 skill points, so use them wisely, or the player will end up with an ineffective build.
Even two of the same tanks can vary widely based on how its skill points are distributed; these different skill point distributions are known as Builds. They vary between strict melee builds and ranged builds.
For every 15 levels, up to 45, the player may go up to the next Tier, which drastically improves the characteristics of the player's tank and its Barrels, Spawners, Trap layers, or other attributes.
As the player levels up:
 The size of the player's tank and its ammunition size will increase by 1% per level above level 1.
 The tank’s Health will increase by 2 HP per level.^{[1]}
 The Field of View (FoV) will increase.
 The Movement Speed will decrease.
Should the player die, they will respawn at a lower level, which fully depends on their level before they died. It is usually half of the player's level, but below Level 12 they will go down only one level, when they are Level 15 they will get Level 12, and upwards to 30 it depends on score, then level.
Experience Gain
Different game modes have different Experience modifiers.
 FFA, 2 Teams, 4 Teams, Maze and Sandbox has an experience multiplier of x1.
 Domination has an experience multiplier of x2.
 Survival, Tag and Mothership has/had an experience multiplier of x3 (the Mothership game mode has been removed).
Level Table
Level  Tank size  Points Needed  Points to Next Level  Respawn Level 

1  2.000 grid squares  0  4  1 
2  2.020 grid squares  4  9  1 
3  2.040 grid squares  13  15  2 
4  2.061 grid squares  28  22  3 
5  2.081 grid squares  50  28  4 
6  2.102 grid squares  78  35  5 
7  2.123 grid squares  113  44  6 
8  2.144 grid squares  157  54  7 
9  2.166 grid squares  211  64  8 
10  2.187 grid squares  275  75  9 
11  2.209 grid squares  350  87  10 
12  2.231 grid squares  437  101  11 
13  2.254 grid squares  538  113  11 
14  2.276 grid squares  655  132  12 
15  2.299 grid squares  787  151  12 
16  2.322 grid squares  938  171  13 
17  2.345 grid squares  1109  192  13 
18  2.369 grid squares  1301  215  13 
19  2.392 grid squares  1516  241  14 
20  2.416 grid squares  1757  269  14 
21  2.440 grid squares  2026  299  15 
22  2.465 grid squares  2325  333  15 
23  2.489 grid squares  2658  368  15 
24  2.514 grid squares  3026  407  16 
25  2.539 grid squares  3433  450  16 
26  2.565 grid squares  3883  496  16 
27  2.591 grid squares  4379  546  17 
28  2.616 grid squares  4925  600  17 
29  2.643 grid squares  5525  659  17 
30  2.669 grid squares  6184  723  17 
31  2.696 grid squares  6907  791  18 
32  2.723 grid squares  7698  839  18 
33  2.750 grid squares  8537  889  18 
34  2.777 grid squares  9426  942  19 
35  2.805 grid squares  10368  999  19 
36  2.833 grid squares  11367  1059  19 
37  2.862 grid squares  12426  1123  19 
38  2.890 grid squares  13549  1190  20 
39  2.919 grid squares  14739  1261  20 
40  2.948 grid squares  16000  1337  20 
41  2.978 grid squares  17337  1417  20 
42  3.008 grid squares  18754  1502  21 
43  3.038 grid squares  20256  1593  21 
44  3.068 grid squares  21849  1687  21 
45  3.099 grid squares  23536    22 
Achievements


Trivia
 In old versions of Diep.io (April 15th17th 2016), the level cap was 60 instead of 45.
 This meant that Tier 5 did exist at one point.
 The only Tier 5 tank back then was Octo Tank, when Quad Tank upgraded from Triple Shot.
 This meant that Tier 5 did exist at one point.
 Should the player kill someone over 23,536 EXP, they will only receive 23,537 EXP. This may be so that a player cannot gain 1m points from an opponent immediately, which would be unfair.
 In FFA and Maze, if a player is 20 Levels higher than an opponent, and they then kill that opponent, there will be a nokill notification. This is intended to prevent the spawnkilling of lowlevel tanks by higherlevel ones.
 It is possible to become higher than Level 45. Players can do this by taking control of a Dominator in Domination, or being the Mothership (before the game mode was removed). This would make the player levels 75 and 140, respectively.
 The formula for tank size is 50 * 1.01^(level  1) units, where a grid square is 25 units.
 While Dominators appear to be level 75, their size corresponds to around level 118, for unknown reasons.
Bugs
This section contains bugs related to Levels. Before adding a bug to this list, consider the following:

Click to Show Bug List 

Unpatched Bugs
