Quarterly Estimated Tax Calculator 2026
Enter your expected 2026 income and deductions. Instantly see your quarterly payment amounts using both the 90% current-year method and the prior-year safe harbor — plus how much each retirement contribution or deduction reduces every quarterly check.
Calculate your 2026 quarterly estimated payments
Designed for sole proprietors and single-member LLCs filing Schedule C. S-corp owners: your W-2 withholding typically covers this — see the S-Corp Payroll Setup Guide.
Estimated 2026 federal tax breakdown
Safe harbor options — both avoid the underpayment penalty4
Pay at least one of these annually (spread evenly across four quarters):
—
2026 quarterly payment schedule
Based on the recommended method above. Pay via IRS Direct Pay or EFTPS — checks risk postmark delays.
| Quarter | Income period | Due date | Payment |
|---|---|---|---|
| Q1 | Jan 1 – Mar 31 | April 15, 2026 | — |
| Q2 | Apr 1 – May 31 | June 15, 2026 | — |
| Q3 | Jun 1 – Aug 31 | September 15, 2026 | — |
| Q4 | Sep 1 – Dec 31 | January 15, 2027 | — |
| Total annual payments | — | ||
Estimates use the standard deduction only — no itemized deductions, QBI, AMT, NIIT, or state tax. Sole prop / LLC Schedule C filers only. Your actual tax may differ; consult your CPA before finalizing payment amounts.
How quarterly estimated taxes work
The IRS operates on a pay-as-you-go system. W-2 employees satisfy it automatically through paycheck withholding. When you're self-employed, there's no employer to withhold — so the IRS requires four prepayments throughout the year instead.1
If you expect to owe $1,000 or more in federal tax at filing, estimated taxes are required. Miss a payment (or pay too little), and the IRS charges an underpayment penalty calculated at the current federal short-term interest rate plus 3 points — even if you pay in full by April 15.
The two safe harbors — how to eliminate the penalty
You avoid the underpayment penalty entirely if your estimated payments (plus any withholding) cover at least one of two thresholds:4
| Method | Annual target | Quarterly payment | Best situation |
|---|---|---|---|
| 90% current-year | 90% of your 2026 actual tax liability | ~22.5% of estimated annual tax | Income is falling from last year |
| Prior-year 100% | 100% of your 2025 total tax | Prior year tax ÷ 4 | Prior year AGI ≤ $150,000 |
| Prior-year 110% | 110% of your 2025 total tax | (Prior year tax × 1.10) ÷ 4 | Prior year AGI > $150,000 |
The prior-year safe harbor's key advantage: it's a known, fixed number. Pay $18,700/quarter based on last year's $68,000 tax bill and you are penalty-proof — even if your 2026 income doubles and your actual tax comes out to $180,000. You'll owe the balance in April 2027, but no penalty. This is why most CPAs recommend the prior-year method for self-employed clients with variable or growing income.
How retirement contributions reduce each quarterly payment
Retirement contributions are among the most impactful levers for reducing estimated taxes because they reduce both federal income tax and (indirectly, via reduced AGI) the effective marginal rate. However, they do not reduce the SE tax base — SE tax is calculated on net Schedule C profit before retirement contributions.
Without any deductions: estimated annual tax ≈ $83,700 → quarterly payment ≈ $18,833 (90% method)
With $60K solo 401(k) + $18K health insurance: estimated annual tax ≈ $63,900 → quarterly payment ≈ $14,378
Savings: ~$4,455 less per quarter — just from above-the-line deductions. Use the calculator above to see your own numbers.
The retirement contribution also reduces your AGI, which can pull you under the QBI phase-out threshold ($201,775 single / $403,550 MFJ), recover your § 199A deduction, and reduce IRMAA exposure in future years. All from the same contribution.
Why the quarterly amounts aren't always equal
The schedule above shows four equal payments — which is the standard approach and satisfies the IRS safe harbor test. In reality, your payments don't have to be equal as long as the total for the year meets the safe harbor threshold. Two situations where unequal payments make sense:
- Annualized income method (Form 2210, Schedule AI): If your income is seasonal — a large Q4 consulting contract, farm income, irregular freelance revenue — you can calculate each quarter's payment based on income actually earned through that period. This requires an extra schedule on your return but avoids overpaying in early quarters when income hasn't materialized yet.
- December retirement contribution strategy: If you make a large solo 401(k) or SEP IRA contribution in December, it reduces your annual estimated tax liability. Some CPAs will adjust the Q4 payment downward to reflect this, since the contribution is made before year-end.
S-corp owners: estimated taxes work differently
If you've elected S-corp status, you pay yourself a W-2 salary with normal withholding already deducted. That withholding may cover all or most of your estimated tax obligation automatically — which is one of the administrative advantages of the S-corp structure.
If you have a gap (common when distributions are large relative to salary), the cleanest fix is increasing supplemental federal withholding on your owner W-2 rather than making separate quarterly payments. Your payroll software can hold any flat additional withholding amount per paycheck.
See: S-Corp Payroll Setup Guide — includes how to set W-4 supplemental withholding to eliminate quarterly payment obligations.
State estimated taxes
This calculator covers federal tax only. Most states with income taxes require their own quarterly estimated payments on a similar calendar. California, New York, Illinois, Massachusetts, and most other high-tax states follow the same Q1/Q2/Q3/Q4 schedule. A few states differ — verify your state's due dates separately. States also have their own safe harbor rules, typically 100% of prior year state tax (not 110%).
Seven states have no income tax: WA, TX, FL, NV, WY, SD, AK — no estimated state payments required if you're in one of these.
Related calculators and guides
- Self-Employed Tax Calculator 2026 — full annual SE tax + FIT estimate with retirement contribution slider
- Quarterly Estimated Taxes Guide 2026 — detailed safe harbor rules, underpayment penalty math, and cash-flow strategies
- Solo 401(k) 2026 Rules and Limits — how contributions reduce your quarterly payments; $24,500 employee deferral + 20% employer contribution
- SEP IRA 2026 — October contribution deadline gives flexibility to wait until you know your annual income before contributing
- Full Self-Employed Tax Deduction Guide — every deduction that lowers your quarterly estimated payment
- S-Corp Payroll Setup — how W-4 withholding on your owner salary can replace quarterly estimated payments
Get your quarterly payment strategy reviewed by a specialist
Estimated tax is a cash-flow management problem as much as a tax calculation. A fee-only advisor specializing in self-employed clients can coordinate your quarterly payments with retirement contribution timing, health insurance strategy, and S-corp salary elections — so you're never paying the IRS more than necessary or risking an underpayment penalty.
- Estimated tax requirements — $1,000 threshold, pay-as-you-go system for self-employed: IRS: Estimated Taxes for Business Owners · IRS Form 1040-ES Instructions 2026 · IRS Pub. 505, Tax Withholding and Estimated Tax (2026).
- 2026 SE tax — 15.3% on net SE income × 92.35% up to $184,500 SS wage base; 2.9% Medicare only above that. SE deduction = 50% of SE tax (IRC § 164(f)): IRS Self-Employment Tax · SSA Contribution and Benefit Base 2026 ($184,500).
- 2026 standard deduction ($16,100 single, $32,200 MFJ) and federal income tax brackets per IRS Rev. Proc. 2025-32: IRS 2026 Inflation Adjustments (OBBBA) · Tax Foundation 2026 Brackets.
- Estimated tax safe harbors — 90% current-year / 100% or 110% prior-year (110% when prior AGI > $150,000, per IRC § 6654(d)(1)(B)): IRC § 6654 — Failure to Pay Estimated Income Tax (Cornell LII) · IRS Pub. 505, Chapter 2: Estimated Tax for 2026. The $150,000 AGI threshold is a statutory fixed amount, unadjusted for inflation since 1998.
Tax values verified as of May 2026. Calculator covers federal estimated tax only; state estimated tax requirements vary by jurisdiction. Designed for sole proprietors and single-member LLCs filing Schedule C.