"Contract size

I note the position size calculator has changed.

What is the 'contract size' on the new iteration of the calculator, and how do I know what the contract size is? Does this vary with different brokers?

I don't know about the calculator but I the contract size is different at different brokers.

Generally when dealing with Forex, the contract size is the same everywhere, ie 1 lot = 100 000 units. With the advent of CFD's for commodities, Indexes, Crypto, and so on, they have had to get creative with what 1 lot is.

You can imagine 100 000 units of bitcoin is hardly a practical size as BTC costs close to $10 000(or whatever it's price is today). BTC will therefore , generally have a contract size of 1.

Because there is no real definition of what 1 lot is outside of forex, brokers are free to set the contract size for 1 lot to whatever suits their operation, so it differs from broker to broker. Take Oil for example, at IC Markets, 1 lots of oil = 100 barrels, whereas at FP Markets 1 lot = 1 000 barrels.

The contract size can be viewed within MT4 terminal by right-clicking on the instrument in the Market Watch window and selecting 'Specification'.