Who Must Pay Estimated Tax (Form 1040-ES) When You Have W-2 + 1099 Income
Not tax advice. This page restates, at a high level, what the IRS publishes about estimated tax. It is not a substitute for Form 1040-ES, Publication 505, or a CPA / enrolled agent. Shortell Designs is not a CPA. Dollar thresholds and safe-harbor percentages can change — confirm on IRS before you decide whether to pay.
Why W-2 + 1099 earners ask this question
W-2 withholding covers the wage job. Self-employment / gig income usually has no federal income-tax withholding and may also trigger self-employment tax (Social Security and Medicare) figured on Schedule SE. Estimated tax is how many people pay that gap during the year instead of waiting until they file.
The IRS overview: Estimated taxes. Form package: About Form 1040-ES.
Who generally must pay (high level)
Per the IRS estimated-tax page, individuals (including sole proprietors, partners, and S corporation shareholders) generally have to make estimated tax payments if they expect to owe tax of $1,000 or more when their return is filed. Exact “who must” tests, including the smaller-of withholding tests, live on the current Form 1040-ES worksheet — confirm on IRS; do not rely on this summary alone.
- Estimated tax covers income tax and can also cover other amounts such as self-employment tax (see the same IRS overview).
- If you receive salaries or wages, you may be able to increase W-2 withholding (Form W-4) instead of making separate estimated payments — again, confirm on IRS.
- Special rules exist for farmers, fishermen, and certain higher-income taxpayers (Publication 505).
Who may not have to pay (high level)
The IRS lists conditions under which you may not have to pay estimated tax for the current year (for example, no tax liability for the prior year, plus other residency / full-year conditions). Read the current wording on Estimated taxes and the Form 1040-ES instructions. This page does not invent an exception list.
Underpayment penalty (high level)
If you do not pay enough through withholding and estimated payments, you may owe an underpayment penalty — even if you are due a refund at filing. The IRS discusses common ways taxpayers avoid the penalty (for example, owing under a stated dollar amount after withholdings/credits, or paying a stated percentage of current-year or prior-year tax). Those percentages and exceptions are fact-specific and change for some taxpayers — confirm on IRS in Publication 505 and Form 2210 materials.
How to pay
Pay through official IRS channels such as Direct Pay, your IRS online account, or EFTPS — not through a sales page or spreadsheet. Calendar-year installment dates for tax year 2026 are summarized on our 2026 estimated-tax dates guide (sourced to Form 1040-ES).
Related guides
- Tax season 2027 hub Overview of TY2026 prep / 2027 filing for W-2 + 1099 + 1040-ES.
- 2026 Form 1040-ES due dates Apr 15, Jun 15, Sep 15 2026, and Jan 15 2027.
- OASDI wage base & SE tax How SE Social Security tax shares the wage base with W-2 Box 3.
Official sources to re-check
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Buy the $29 Excel kit on GumroadDisclaimer (not tax advice)
Not tax advice. Educational planning copy only. Shortell Designs is not a CPA, not a tax preparer, and does not offer a professional tax service. Confirm every threshold and exception on current IRS pages before you pay estimated tax or file a return.