# Ticks

### What are ticks

To enable concentrated liquidity, Reactor splits the continuous price curve into discrete intervals called ticks.\
One tick equals a 0.01% price move up or down, independent of the current price level.\
An LP position is defined by a lower tick and an upper tick. Liquidity is active only within that range.

### How swaps move through ticks

During a swap, the protocol consumes liquidity in the current tick range.\
When that range is exhausted, execution moves onto the next tick.\
If positions exist at the boundary, their liquidity turns active.

### Pool structure and tick spacing

All pools share the same underlying tick grid, but not every tick is usable. Availability is controlled by tick spacing, which depends on the selected fee tier:

* Lower fee tiers (for example 0.01%) allow tighter spacing and more granular liquidity placement.
* Higher fee tiers (for example 1%) increase spacing and limit where positions can be set.

Crossing a tick does not incur gas by itself.\
Swaps that cross active ticks can have slightly higher transaction cost because a new set of liquidity is activated.
