Micro lot

A micro lot shows as 0.01 on MetaTrader or cTrader. It equals 1,000 units: on EUR/USD, one pip is then worth about $0.10. It is the ideal size to start trading live with a small account, or to test a strategy without putting much money on the line.

Above all, it lets you fine-tune your position size. If your calculation gives 0.37 lot to risk 1% of the account, you can enter exactly that instead of rounding to 0.4 or 0.3.

Some brokers also offer nano lots (0.001 lot, 100 units), useful on accounts of a few hundred.