Contract Size

What is contract size?

Contract size is the fixed quantity of an underlying instrument that one full lot represents. It’s the standardization that lets traders and brokers quote position sizes consistently, and it’s the key input — along with the exchange rate — for calculating how much money a single price move is worth on a given trade.

In spot forex, the contract size for one standard lot is conventionally 100,000 units of the base currency. A mini lot is 10,000 units (one-tenth of a standard lot), and a micro lot is 1,000 units. Other instruments have their own contract-size conventions — for example, a gold (XAU/USD) CFD contract is often standardized at 100 troy ounces per lot, and index or share CFDs each carry their own broker-defined contract size.

A worked example

Take EUR/USD with a contract size of 100,000 units per standard lot. If you open 0.5 lots, you are controlling 50,000 units of EUR — half a standard contract. Since pip value scales directly with contract size, a pip on that 0.5-lot position is worth roughly $5 (half of the ~$10 pip value of a full standard lot). This is exactly how brokers translate a chosen lot size into a real, calculable pip value for your trade ticket.

Why contract size matters

Contract size is the multiplier behind every pip-value and margin calculation a broker’s platform shows you. Two traders holding “1 lot” of different instruments — say EUR/USD versus a gold CFD — are controlling entirely different notional exposures, because each instrument’s contract size differs. Before trading any new instrument, it’s worth checking its contract size in the broker’s specification sheet, since this single number determines both the potential reward and the risk of every price tick, and feeds directly into required margin and appropriate position sizing.

Contract sizes vary by broker and instrument — always confirm the exact specification in your broker’s contract specifications before trading. This article is educational and not financial advice.