Hi brooke27
The way I would do it and I would strongly recommend speaking to your accountant/the ATO would be:
- Determine what the gross amount for the total wages for the period would be
- Use the ATO calculator to determine what the overall total amount should be
- With that Total amount value minus what has been calculated to give the amount required for that pay
However, as there are some thresholds and other components that make up tax it is recommended that you do speak to your account/the ATO to ensure you have right tax amount for your employees.