1099 Quarterly Tax Calculator
As a 1099 contractor, freelancer, or self-employed worker, the IRS expects four estimated tax payments per year — April, June, September, and January. This calculator figures out how much each one should be.
Estimated quarterly payment
Per quarter
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Annual tax owed
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Self-employment tax
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Federal income tax
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State income tax
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SE deduction (federal)
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Effective tax rate
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Why self-employment tax exists
If you're a W-2 employee, your employer pays half of Social Security and Medicare (7.65%) and you pay the other half. As a 1099 contractor, you ARE the employer — so you owe both halves, called self-employment tax at 15.3% (12.4% SS + 2.9% Medicare).
The good news: you get to deduct half of SE tax (the "employer half") from your federal taxable income. The calculator handles that automatically.
The quarterly deadlines (2026)
- Q1 (income Jan–Mar): due April 15, 2026
- Q2 (income Apr–May): due June 15, 2026
- Q3 (income Jun–Aug): due September 15, 2026
- Q4 (income Sep–Dec): due January 15, 2027
Note the uneven quarters — Q2 covers only April and May. The IRS calls them "estimated tax periods" for a reason; they're not even calendar quarters.
Safe harbor — when you can underpay without penalty
To avoid an underpayment penalty, your quarterly payments need to total either:
- 90% of your current year's tax liability, OR
- 100% of your prior year's tax liability (110% if AGI > $150k)
Most people use the prior-year safe harbor — pay the same total as last year and you're fine, even if this year's income is much higher.
What this calculator doesn't cover
- Local city / county income taxes (NYC, Philly, OH municipalities)
- Qualified Business Income (QBI) deduction — many 1099 workers qualify for a 20% reduction in federal taxable income; check Form 8995
- Above-the-line deductions: SEP-IRA, Solo 401(k), self-employed health insurance, half of SE tax (handled)
- State estimated tax deadlines (most match federal but some don't)
FAQ
What if I underpay quarterly?
The IRS charges an underpayment penalty (about 8% APR on the shortfall, 2026 rate). It's not a fine — it's interest. Hitting the prior-year safe harbor avoids it entirely.
What if my income is wildly uneven?
You can use the "annualized income installment method" (Form 2210, Schedule AI) which lets you compute each quarter based on income earned in that quarter only. More paperwork, but fair if you had a big Q4 windfall.
Do I still file an annual return?
Yes. Quarterly payments are just prepayments; the annual return (Form 1040 + Schedule SE + Schedule C) reconciles them against what you actually owe. If you overpaid, you get a refund; if you underpaid, you pay the balance.
Can I skip quarterly and pay it all in April?
Only if you owe less than $1,000 in tax for the year. Above that, the IRS expects pay-as-you-go and assesses underpayment penalties on each missed quarter.
What if I have both W-2 and 1099 income?
Enter the W-2 wages as "Other income." Your W-2 employer's withholding doesn't cover your 1099 income, so quarterly payments still apply to the 1099 piece (plus any underwithholding on the W-2).