Range is a game mechanic in the BTD series. It is the limit of where a tower can detect bloons to attack. It is signified by a dark circle around towers. Contrary to popular belief, the range is not the limit of where it can attack but the area where it can detect bloons to attack.
A very important tip is to make the dark circle touch the track's path. If this wasn't made, the tower won't be able to attack Bloons. The exceptions are towers with infinite range. For these towers, you will not have to worry about them not attacking Bloons, so feel free to place them where ever you like. There is an exception though, in BTD6.
In Bloons Tower Defense 6, a tower's range can be restricted by sight-blocking objects in the track, by a feature called "Line of Sight". This applies to both limited range towers and infinite range towers. For example, if a bloon is in a Super Monkey's range circle, but the bloon is behind a rock and the tower can't "see" it, the Super Monkey won't attack the bloon. Areas where sight is blocked in BTD6 are colored red.
The range circle for towers can be turned off in Bloons Tower Defense 6 by the "Line of Sight" option, for performance purposes. This is the only BTD game that has this option. This option has however since been removed.
- Monkey Villages don't attack using range until upgraded to High Energy Beacon. Instead, they help support all towers within its range.
- The Pontoon Pro does not grant a range boost to the Meerkat Spy.
- The Super Monkey can attack bloons slightly out of it's range.
- If a bloon is off the map, but there is a tower with enough range to see the bloon if it is on the map, then said tower will attack the bloon. This doesn't happen with towers that have unlimited range, except for the Ray of Doom. However, Sniper Monkeys may attack bloons that are "off" the screen but haven't leaked yet.
- In Bloons Tower Defense 5, the range circle will go above towers when you place a tower near another tower. However, in Bloons Tower Defense 5 Deluxe, the circle will go below the tower, making Temple of the Monkey Gods harder to fit together.
- The highest finite range possible in BTD5 is the Temple of the Monkey God upgrade with Epic Range with a 1/x Monkey village, Tier 2 Super Monkey Lair activated, and on a Pontoon Pro. In BTD5 Mobile, it would be the same, except the Temple of the Monkey God would be replaced with a Temple of the Vengeful Monkey.
- In relation to the Advanced Intel upgrade for the Monkey Sub, infinitely ranged towers have their circle as their range.
- All towers can attack MOAB-class bloons slightly outside their range. This is because MOABs are bigger than standard bloons.