Contract size, also known as lot size, in MetaTrader is essentially the number of units of a financial instrument that a trader is buying or selling in a particular trade. This measurement is very important because it directly affects the risk and profit of a trade.
In Forex trading on MetaTrader, the standard contract size is 100,000 units of the base currency. This is referred to as a 'standard lot'. However, there are also smaller lot sizes:
Remember to check your broker's specific contract sizes, as they can sometimes differ from these standard sizes.
Having the right contract size is important for the position size calculator to do it's thing correctly. Otherwise the lot size won't match. To check the contract size, you can simply click on the instrument and select details. The contact size will be there.