Experience Points

, or XP, are a value to describe a player's progress in the Bloons Tower Defense games. This feature was first introduced in Bloons TD 4. Popping an individual bloon earns XP, and contributes to leveling up Ranks ("Levels" in BTD6).

In Bloons TD 4 and Bloons TD 5 it is awarded for popping Bloons. The player gets 1 XP point per 1 Bloon popped but the XP gained for popping bloons is not equal to RBE. For example, reducing M.O.A.B. to Ceramic Bloons takes 200 hits so 200 points to RBE but since it only registers as one pop, the player will only receive a single XP point. The player gets a new Rank when they reach certain amounts of XP.

In BTD4, the bar showing how much XP you had also showed how many more bloons you had to pop before you go up a rank. In BTD5, the information is shown as pop up message when the player hovers the mouse over the XP bar. Bloons also give less XP starting at round 71.

XP works similarly in Bloons TD 6 compared to BTD5.

Towers
Refer to Tower XP (BTDB2).

BTD6 Heroes XP
Heroes gain a fixed amount of experience each round according to the formula for Tower XP. It does not matter how many Bloons they pop. The base heroes (Quincy, Gwendolin, Striker Jones, Obyn Greenfoot) and Etienne all require the same amounts of experience to level up. Other heroes require a certain multiple more XP compared to the base heroes.


 * Ezili, Pat Fusty, Admiral Brickell and Sauda all require 1.425x more XP compared to the base heroes.
 * Benjamin and Psi require 1.5x more XP compared to the base heroes.
 * Churchill requires 1.71x more XP compared to the base heroes.
 * Adora also requires 1.71x more XP compared to the base heroes. However, using her "Blood Sacrifice" ability allows her to sacrifice a tower and gain 4x the money spent on the tower as XP.

Bold lines represent levels where it requires LESS experience than the level before it. 

BTD5
This is how much XP the bloons give in certain rounds:
 * Rounds 1-70: Bloons give 100% XP
 * Rounds 71+: Bloons give 30% XP

The player also gets Tower XP in BTD5 (with the same multiplier applied to bloons after round 70). The more money that is spent on a type of tower, the more Tower XP for the type of tower is gained. Certain amounts unlock new tower upgrades for each tower. Final upgrades must be unlocked also by reaching a certain Rank, such as the Ray of Doom. The path 1 upgrades usually require less XP than the path 2 ones (An exception is Arctic Wind).

XP for tower = (RBE for round) * (sell value for tower) / (sell value for all towers)

BTD6
In BTD6, the XP-gaining structure is different. Instead of automatically unlocking upgrades, the player gets to choose which upgrades can be unlocked for a tower. Each tower has a different set of XP collections, and more XP can be generated by using a certain tower more often.

Unlocking a tower with XP requires the previous upgrade tier to be unlocked, so for example, Very Quick Shots cannot be unlocked unless Quick Shots is also unlocked.

To see how much XP is required for each towers' upgrades, please see each respective towers' pages.

XP for towers in BTD6 is calculated in the following way. Each round has a set amount of XP that it gives, regardless of bloons popped. At the end of the round, this XP is added to your account and is split between the towers you have placed relative to the amount of money spent on each tower. for example, a defense of $100 ninja, $100 druid, and $200 alchemist on a round that gives 100 XP will give 25 XP to the ninja, 25 to the druid, and 50 to the alchemist. Heroes do not count as towers in this scenario.

Round 1 starts off with 40 XP, and up until round 20 this amount increases by 20 each round (40 XP, 60 XP, 80 XP...). Then on rounds 21-50 the amount experience gained each round increases by 40 each round (460 XP, 500 XP...). And last, from round 51 and further, this amount increases by 90 each round (1710 XP, 1800 XP...). Adding this up, you get a total of 231,150 XP in a game from round 6 to round 100 on Impoppable or C.H.I.M.P.S.. Each map difficulty above beginner gives a 10% xp bonus, e.g. playing on expert gives you a 30% XP boost. Upon reaching freeplay mode, you gain 30% of the normal XP, and after round 100 (if on freeplay mode), 10% of the normal XP, although heroes will not be affected by the cut at this point.

BTD6 Tower XP Requirements
Table is up to date as of Version 25.0.

XP in BTD4
The max rank is 94 by getting 10 quadrillion XP.

XP in BTD5
The max rank is 200 by getting 150 billion XP.

XP in BTD6
Maximum level is Level 155, after which you begin to earn Veteran Levels.

Refer to Career Rank for information about rewards for leveling up.

XP in BMC

 * See also: City Level

In this game, players gain various amounts of XP by doing any of the following Some upgrades and buildings require a certain City Level (similar to rank in other BTD games) before being bought. Once the player gains enough XP, their city levels up.
 * Capturing new tiles
 * Building facilities/buildings in their town
 * Buying upgrades for the towers in the upgrade buildings
 * Completing quests

Demolishing building leads to you being "in debt" to experience points. This cannot cause you to lose levels, and shows how much more you need to earn to start gaining experience again.

BATTD
XP is earned by completing Adventures, regardless of difficulty and map. They can also be earned by replaying an already completed map or playing on Bloon Beacon. Leveling up rewards +$5 starting cash per new level, up to Level 100 for +$495 starting cash.

Tips

 * In BTD5, the player can replay the Daily Challenges Third Time's A Charm (July 2nd, 2012), The Daring Dozen (January 27th 2014) or 20 Ceramics on the Wall (July 30th, 2012) to earn millions of Experience Points.
 * In Freeplay Mode of BTD5, the amount of experience gained per popped bloon slowly goes down per round, gradually making it an ineffective way to gain experience.
 * More information about gaining Experience Points quickly can be found in the Experience Point Farming article.
 * In BATTD,some people got over level 100 back when xp per level was lower and it was uncapped.That is a bug and you may see someone like lv103. There is no extra xp in the festival loot. There is no extra xp in the beacon loot. You can get double exp using the "double reward". In fifth difficulty maps like "black heart" ,imp, 75r,you will get the most xp -300xp. But hard mode in this map has 45r 150xp, It is very efficient.

Trivia

 * In BTD5, the maximum amount of XP is 179,995,343,055,540,813,000, while the player is still at Rank 200 with that amount. The amount needed to go to the next Rank (with the maximum amount) is -179,995,343,055,539,813,000.
 * This is due to an integer overflow.
 * On the Daily Challenge 20 Ceramics on the Wall, the player can earn about 5000 XP by playing Rounds 1-70, then keep repeating to reach higher Ranks.