The ratio between a position's notional value and the margin required to open it.
Leverage is forex's most powerful and most misunderstood feature. At 30:1, a trader can control a USD 30,000 position with only USD 1,000 of account equity posted as margin. The appeal is obvious: a 1% move in the pair produces a 30% return on margin. The danger is equally direct - that same 1% adverse move produces a 30% loss and can trigger a margin call if risk is not carefully managed.
Regulators have responded to retail leverage-related losses by imposing strict caps. The European Securities and Markets Authority (ESMA) and the FCA in the UK cap retail leverage at 30:1 on major currency pairs and 20:1 on minors; ASIC in Australia applies the same limits. The CFTC in the US caps retail forex leverage at 50:1 on majors and 20:1 on others. Offshore or unregulated brokers frequently advertise 500:1 or higher, which is a significant risk warning in itself. Professional clients who qualify can access higher leverage tiers under most regulatory regimes.
Practical position sizing rarely calls for maximum leverage. A trader risking 1% of a USD 10,000 account (USD 100) on a 20-pip EUR/USD stop is effectively using only 5:1 leverage regardless of the account's maximum. Thinking about leverage in terms of actual position risk - rather than headline ratio - is a more useful discipline and prevents the common mistake of over-sizing simply because leverage is available.
Worked Example
Account equity: $2,000. Leverage: 30:1. Maximum position: $60,000 (0.6 standard lots of EUR/USD). A 1% move in EUR/USD = $600 - a 30% swing on the $2,000. Using 1% risk discipline instead: risk $20, 20-pip stop, pip value $10/lot → position = 0.1 lots, actual leverage used = ~5:1, far below the 30:1 maximum.