Taxes · 2026
Quarterly Estimated Tax Calculator
Estimate what to send the IRS each quarter. The safe harbor figure matters more than the exact liability because it can generally protect you from an underpayment penalty.
Your own wages reduce the Social Security wage base remaining for Schedule SE.
Included in household income and Additional Medicare tax, but not in your Social Security wage base.
Interest and other ordinary income. Do not include capital gains in this simplified estimate.
Withholding counts as paid evenly across the year, no matter when it happened.
Line 24 of your 2025 Form 1040. This drives the safe harbor.
- Projected total federal tax
- $19,316
- Self-employment tax
- $12,717
- Additional Medicare tax on W-2 wages
- $0.00
- Federal income tax
- $6,599.34
- QBI deduction (199A)
- $13,508
- Taxable income
- $54,033
- Safe harbor amount
- $0.00
- Payment based on
- 90% of this year’s projected tax
- Effective rate on net profit
- 21.5%
- Marginal income tax rate
- 22.0%
- Note
- Enter last year’s tax to unlock the safe harbor
Transparent method
How this calculator works
- Estimate Schedule SE tax, Additional Medicare tax, federal taxable income, and regular income tax using 2026 rates.
- Compare 90% of projected current-year tax with the applicable 100% or 110% prior-year safe harbor.
- Subtract withholding and divide the remaining required annual payment into four installments.
What the result does not include
- Credits, itemized deductions, capital gains, AMT, net investment income tax, state tax, and several new 2026 deductions are excluded.
- Above the QBI threshold, only the statutory minimum QBI deduction is included because wage, property, and SSTB limits require more facts.
Common questions
What is the safe harbor and why does it matter more than the exact number?
If you pay at least 100% of last year’s total tax — generally 110% if prior-year AGI was over $150,000, or $75,000 when married filing separately — you generally avoid an underpayment penalty, no matter how much more you end up owing. For a growing business that is usually the cheaper target: you pay less during the year and settle the rest at filing without penalty.
When are the payments due?
Roughly April 15, June 15, September 15, and January 15 of the following year. The quarters are not equal lengths, which surprises people — the second "quarter" covers only two months.
What if my income is uneven?
Paying a flat quarter of the year’s total can overpay early if you earn most of your income late. The annualized income installment method on Form 2210 lets you match payments to when you actually earned, at the cost of more paperwork.
Does withholding from a job count?
Yes, and it is treated as paid evenly through the year regardless of when it was withheld. If you have a spouse with a W-2, increasing their withholding late in the year can retroactively cure an underpayment that quarterly checks cannot.