A surprisingly common calculator error is assuming that every “one lot” of gold represents the same amount of metal on every platform. Lot size is a contract specification, not a universal natural unit.
Ounces are the economic exposure
A gold position specified as 10 troy ounces gains or loses $10 for each $1/oz change in the quoted USD gold price, before costs. This statement does not depend on how a broker names its trading volume. A platform may define one lot using a particular number of ounces and expose smaller increments.
Futures provide a useful counterexample
CME describes the standard COMEX Gold futures contract as 100 troy ounces, with smaller related products also listed. That does not imply a retail XAU/USD CFD lot is always the same 100 ounces. Futures and OTC CFDs have different contract structures and margin frameworks.
How to check your platform
Open the instrument’s specification screen and record contract size, quote currency, tick size, tick value, minimum volume and volume step. MetaTrader documents symbol specifications; the current values come from the connected broker.
If the platform lists one lot as 100 ounces and you trade 0.10 lots, the implied exposure is 10 ounces. At a $25/oz price change that is about $250 gross P/L. But if that symbol has a different contract size, the result changes.
- Never infer contract size from a different broker’s website.
- Check min/max lots and step increments.
- Confirm whether account conversion is required.
- Calculate in ounces first, then convert to platform units.
Why our gold calculator uses ounces
Our tool takes troy ounces as the input to make the multiplication explicit. It does not pretend to know the lot configuration or contract multiplier of a broker that the user has not specified.
XAU/USD gold profit & loss calculator
Change assumptions yourself. This free calculator uses transparent arithmetic; it does not predict a strategy’s future results.
Open interactive calculator ↗