How do I track expenses for a side business next to my job?

Updated October 29, 2026By ProfitDrawer

Short answer

Use a separate account or card for the side business, record each expense with its date, amount, category and receipt, and keep it apart from household spending and your paycheck. For the 2026 tax year, filed in 2027, you generally owe self-employment tax and file Schedule SE if net earnings from self-employment are $400 or more. A ProfitDrawer side hustle tracker keeps side income, expenses and mileage in one file with a Tax Summary tab.

Practical setup:

Separate the money. A second checking account or a card used only for the side business makes the records almost automatic.
Pick a few categories, such as supplies, platform fees, advertising, software, phone (business share) and postage.
Save receipts the same day, as a photo or file.
Log business miles with date, purpose and miles.
Update weekly and review totals monthly.

Things specific to a side business:

Your job's withholding does not cover side profit. If you expect to owe $1,000 or more, you may need quarterly estimated payments, or you can raise withholding at your job.
Only the business part of mixed costs counts, such as a phone or home internet.
Payment app forms are not the whole picture. Record all income, whether or not you get a 1099.
Losses and hobby questions depend on your facts; ask a tax professional if the business rarely makes a profit.

General information, not tax advice.

Source: IRS: Self-employment tax (Social Security and Medicare taxes) · Updated October 29, 2026