🗓️ Quarterly Estimated Tax Calculator
Enter your numbers to see your required annual payment and per-quarter breakdown.
How Quarterly Estimated Taxes Actually Work
If you're self-employed, run an S Corp, or have significant 1099/business income, the IRS expects you to pay taxes as you earn — not all at once in April. Estimated tax payments cover both your regular federal income tax and self-employment tax (Social Security + Medicare) on income that doesn't have anything withheld automatically.
The Safe Harbor Rule
You can avoid an underpayment penalty entirely by paying the smaller of these two targets over the year:
- 90% of your current year's total tax — requires a reasonably accurate estimate
- 100% of last year's total tax (or 110% if last year's AGI was over $150,000) — guaranteed safe regardless of how this year turns out, even if your income jumps
Most self-employed people with a growing business prefer the prior-year method — it's simpler and fully protects against a penalty even in a big growth year.
2026 Quarterly Due Dates
| Payment | Due Date | Covers Income From |
|---|---|---|
| Q1 | April 15, 2026 | January – March 2026 |
| Q2 | June 15, 2026 | April – May 2026 |
| Q3 | September 15, 2026 | June – August 2026 |
| Q4 | January 15, 2027 | September – December 2026 |
Notice the periods aren't equal — the IRS's quarters are 3, 2, 3, and 4 months long, respectively. This calculator still splits your required payment into four equal installments, which is the standard method most filers use.
What This Calculator Includes
- Self-employment tax (15.3% on 92.35% of net profit, with the Social Security portion capped at the 2026 wage base of $184,500)
- The above-the-line deduction for half of your self-employment tax
- 2026 federal income tax brackets and standard deduction for both Single and Married Filing Jointly
- Child Tax Credit ($2,200/child under 17) and Credit for Other Dependents ($500 each), with the 2026 phase-out applied above $200,000 (single) / $400,000 (MFJ) AGI
- Safe harbor comparison against your prior year's actual tax liability
Your Numbers Are Completely Private
Every number you enter is processed entirely in your browser. Nothing is ever transmitted to a server, stored in a database, or shared with anyone.
- This calculator does not include state estimated taxes, which many states require separately and on their own schedule.
- It does not include the 0.9% Additional Medicare Tax that applies above certain income thresholds.
- It does not apply the Qualified Business Income (QBI) deduction, which can deduct up to 20% of eligible business income. If you qualify, your actual income tax may be lower than shown, so treat these results as a conservative (higher) estimate.
- It uses the standard equal-installment method, not the Annualized Income Installment Method for uneven income.
- This is for educational and planning purposes only, not tax advice. Consult a licensed CPA or tax professional for your specific situation.
Frequently Asked Questions
Already Behind With the IRS?
If you missed payments and now owe more than you can pay at once, don't ignore IRS notices. Penalties and interest keep growing. You can request a payment plan yourself at IRS.gov, often online in minutes. If your situation is more complicated (several years owed, liens or wage garnishment), a tax resolution firm can negotiate with the IRS on your behalf.
Want to see how your bracket affects these numbers? Read 2026 Tax Brackets Explained.