You can use the What If? Planner to forecast next year’s tax liability by following these steps:

1. Open the SA100 tax return in question
2. Go to Check & Finish.
3. Click on What If? Planner
4. Enter the income figures:
   • Click on Use 2023/24 Values and use Add/Edit for each section to adjust the figures – if the information is the same or similar to the current tax year.
   • Click on Add/Edit for each section and enter the projected income in the boxes – if the information is different or you want to enter it manually.
5. Click on Close to build on next year's tax calculation.

When you’ve declared all of the income, you’ll see the estimated final tax liability due for next year.

Please Note: This information doesn’t get filed online so you’ll still need to complete the tax return as required for that tax year.