What is a lot, and how is lot size calculated?
Quick answer
A lot is a standard unit of trade size. In forex, one standard lot is 100,000 units of the base currency, a mini lot is 10,000 and a micro lot 1,000 (0.01 lots). Other instruments define a lot differently: one lot of gold is usually 100 ounces. Position value depends on the instrument's contract size.
Detailed answer
Traders size positions in lots, but what a lot means depends on the instrument.
Common contract sizes
- Forex: 1 lot = 100,000 units of the base currency. 0.01 lots = 1,000 units.
- Gold (XAU/USD): 1 lot = 100 troy ounces.
- Silver (XAG/USD): commonly 5,000 ounces per lot.
- Oil: often 100 barrels per lot.
- Indices: often 1 contract = 1 unit of the index, priced per point.
- Crypto: often 1 lot = 1 coin.
Sizing a trade from risk
Most traders size positions from how much they are willing to lose:
Lots = money at risk ÷ (stop distance in pips × pip value per lot).
Example: risking $500 on EUR/USD with a 25-pip stop, where one pip on one lot is worth $10, gives $500 ÷ (25 × $10) = 2 lots.
Why it matters for prop rules
Lot limits per order or in total are common prop rules. They only make sense if traders know each instrument's contract size, so publish it.
PropExecutor uses each instrument's real contract specification, read from the broker's own symbol definitions: 100,000 units per lot for forex, 100 ounces for gold, 5,000 for silver, one coin for Bitcoin and Ether, and per-contract sizing for indices, with minimum, maximum and step sizes enforced on every order.
PropExecutor team · Updated
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