The most traded currency pairs, all involving the US dollar: EUR/USD, USD/JPY, GBP/USD, USD/CHF, AUD/USD, USD/CAD, NZD/USD.
Majors have the deepest liquidity and the tightest spreads, often under one pip. They react to central-bank policy (fomc and its counterparts), rate differentials, and risk-on-risk-off flows.
EUR/USD alone accounts for roughly a fifth of global forex volume.
Example: a typical EUR/USD spread is 0.1 to 0.5 pips at a good broker during the london-session, versus 2 to 5 pips on an exotic pair (see exotic-pairs).
Original diagrams for the ideas on this page. Illustrative, not real market data.
The bid-ask spread. Buy orders sit below, sell orders above, and the gap between the best bid (50.01) and best ask (50.04) is the spread you pay to cross. Bar length shows the size resting at each price.
Educational only, not advice. Spotted an error? Post in Site Feedback.