How do I build a budget that includes my side income?

Step by step:

1. Base the budget on your regular paycheck. Cover essentials and minimum debt payments from income you can count on.
2. Track side income and expenses separately, ideally in a separate account, so you know the side business's real profit.
3. Set aside tax first from each side payment. The free self-employed tax calculator shows how much a share you choose sets aside, with the self-employment tax part on its own line.
4. Use your lowest typical side month if you put any side income in the monthly plan. Side income often swings.
5. Assign the rest on purpose the day it arrives: emergency fund, extra debt payments, sinking funds or a specific goal.
6. Review monthly and adjust if the side income grows or shrinks.

Tax points (2026 tax year, filed in 2027): self-employment tax is 12.4% Social Security plus 2.9% Medicare; estimated payments are generally required if you expect to owe $1,000 or more, unless you raise withholding at your job with a new Form W-4. Income is taxable even without a Form 1099.

General information, not tax advice.