2026 Year-End Tax Checklist for W-2 + 1099 Side Hustles
November–December is the last window to fix 2026 before it’s locked. This checklist is for people with a W-2 job plus 1099 side income. Every rule below links to the IRS page it comes from.
1. Check your estimated-tax pace
- The fourth 2026 Form 1040-ES installment is due January 15, 2027. You can skip it if you file your 2026 return by February 1, 2027 and pay the full balance then. (IRS: Form 1040-ES) See 2026 estimated tax dates.
- Not sure you owe quarterly payments? Read who must pay estimated tax.
- W-2 earners can also raise withholding for the rest of the year with a new Form W-4. (IRS Tax Withholding Estimator)
2. Close out your 2026 side-hustle books
- Total gross 1099 income by payer and platform. You must report all income, whether or not you get a Form 1099. (IRS: Understanding your Form 1099-K)
- Match expenses to receipts. Keep the records that support each figure on your return. (IRS: How long should I keep records?)
- Finish your mileage log. 2026 has two business rates, one before July 1 and one after, so log dates as well as miles: 2026 mileage rates.
- Estimate self-employment tax on your net profit: OASDI / SE tax for W-2 + 1099.
3. Know which forms to expect
- Form 1099-K: Payment apps and online marketplaces (third-party settlement organizations) generally must send one only if you got more than $20,000 across more than 200 transactions. Personal payments, such as splitting a bill with friends, are not reportable on it. Platforms may still send one below the threshold. (IRS)
- Form 1099-NEC from clients who paid you as a nonemployee, and Form W-2 from your employer. (IRS: About Form 1099-NEC)
- Update your address and payout email with each platform now so forms reach you. The full list is on filing prep for 2027.
4. Decide how long to keep records
The IRS general rule is 3 years from filing. It is 6 years if you left out more than 25% of gross income, 7 years for a bad-debt or worthless-securities deduction, and at least 4 years for employment tax records. (IRS)
Back to the tax season 2027 hub.
Track it in one workbook
The W-2 + 1099 Tax Reserve Kit ($29, Excel, no VBA) logs side-hustle income, expenses, mileage and 1040-ES reserves in one place, so year-end and filing prep are a lookup instead of a hunt. It is a tracking tool, not tax advice.
Not tax advice. Shortell Designs is not a CPA. Rules and dates change; confirm on IRS.gov or with your tax professional.