> For the complete documentation index, see [llms.txt](https://whitepaper.cryptotd.me/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://whitepaper.cryptotd.me/crypto-td/upgrades.md).

# Upgrades

Towers have the capacity to reach level 3, with the cost of each upgrade contingent upon their rarity. This is determined by the following formula:

$$
Price = Rarity \* 20 + 1000
$$

![Tower upgrade example](/files/6Pf6aCOeeD7YDxYF8WvF)

​Upgrading the tower will boost its stats to the next level. The new stats depends on the tower type and rarity. You will be able to preview the new stats and the price in the upgrade screen before confirming.