# Commissions Commissions can be calculated by MotiveWave™ using the simulated account, in replay mode or as part of Strategy Back Testing. If you would like to include commissions, these can be configured from the Commissions dialog (Configure > Commissions from the Console menu bar). * **Base Cost** – This is the base cost of a trade. Some brokers offer flat rates for commissions. If this is the case, just enter the cost here. * **Unit Cost** – Some brokers charge based on the number of units (ie quantity) that are part of an order (ie shares, contracts etc). * **Unit Size** – If a unit cost has been specified this is the lot size.

The above dialog enables you to define a commission structure that applies to each type of instrument. Some instruments may have their own specific commission structure. If this is the case, you can override this from the **Instrument** dialog (right click on the chart and choose *Edit Instrument,* click on the **Commissions** tab).