Tick

A tick is the smallest possible price change in a financial instrument. In forex, a tick typically equals one pipette — the fifth decimal place for most pairs (0.00001) or the third decimal for JPY pairs (0.001). Tick-by-tick data represents every single price change, providing the highest resolution view of market activity.

For most retail traders, tick data is more granular than necessary. Standard candlestick charts on 1-minute or 5-minute timeframes are sufficient. However, scalpers and algorithmic traders sometimes use tick charts (charts that form a new bar after a set number of ticks rather than a time period) to get a more detailed view of market microstructure.

Tick volume (the number of ticks per time period) is used as a proxy for actual volume in forex. Since the forex market is decentralized, there's no consolidated volume data like in stock markets. Tick volume isn't perfect, but research shows it correlates reasonably well with actual volume and can be useful for confirming breakouts or detecting weakness in a move.