The What If? Planner lets you forecast next year's tax bill. To access the planner, follow these steps:

1. Open your individual tax return (SA100).
2. ​Click on WhatIf Planner from the left hand menu. 

If you have purchased the What If? add on product and this option isn't available, check the following:

• Close and reopen TaxCalc to update your licence.
• Go to Help > Check for Updates.