When you are an employee, your employer withholds income and payroll taxes from every paycheck and sends them to the IRS on your behalf. When you are self-employed, nobody does that for you. The tax system still expects the government to receive your money roughly as you earn it, which is why the IRS requires estimated tax payments four times a year. If you simply wait until April 15 to pay your entire bill, you will usually owe an underpayment penalty plus interest, even if you pay the full amount on time. This page helps you size each payment and check whether you are protected by a "safe harbor."
Who Is Required to Make Estimated Payments
You generally must make quarterly estimated payments if you expect to owe at least $1,000 in federal income tax for the year after subtracting any withholding and refundable credits. For the typical sole proprietor, that bar is easy to clear, because the self-employment tax alone is 15.3% of net earnings. A freelancer with just $7,000 of net profit already owes about $1,071 of SE tax, crossing the threshold. If you also had any W-2 withholding during the year, that withholding counts toward the $1,000 test and can reduce or eliminate what you must pay separately.
The 2026 Payment Calendar
Each payment covers a portion of the year, but the periods are not equal calendar quarters. The installments and their due dates for tax year 2026 are:
If a due date falls on a weekend or a legal holiday, the deadline shifts to the next business day. The fourth payment is due January 15, 2027, which technically covers part of the following year, but paying it keeps you square for all of 2026. You do not have to make the fourth payment if you file your full return and pay the balance in full by January 31.
Worked Example — Equal Installments
Scenario: A sole proprietor estimates total federal tax for 2026 (income tax plus self-employment tax) will be $12,000, with no W-2 withholding.
Divide by four: $12,000 ÷ 4 = $3,000 per quarter.
Payments: $3,000 by Apr 15, $3,000 by Jun 15, $3,000 by Sep 15, $3,000 by Jan 15.
As long as each payment is made on time and the estimate is accurate, no penalty applies. The calculator produces exactly this split when you enter your expected net tax.
The Safe Harbor Rules — Your Penalty Shield
You avoid the underpayment penalty if, by the end of the year, you have paid in enough through withholding plus estimated payments to meet either of two safe-harbor thresholds:
- 90% of the current year's actual tax, or
- 100% of the prior year's total tax (last year's Form 1040, line 24). If your prior-year AGI was more than $150,000 (or $75,000 if married filing separately), the threshold rises to 110% of the prior year's tax.
The safe harbor is powerful because it lets you ignore how much your income grew. If you paid in 100% (or 110%) of last year's tax through timely payments, you owe no penalty even if your actual bill doubled. Many freelancers deliberately base their payments on the prior-year figure for predictability, then settle any remainder when they file.
Safe-harbor example: Last year's total tax was $10,000 and prior-year AGI was below $150,000. This year income surged and the real bill will be $14,000.
Paying 100% of last year ($10,000) spread across four quarters satisfies the safe harbor, so no penalty applies even though the current-year bill is $4,000 higher. The extra $4,000 is simply paid with the return by April 15.
If prior-year AGI had exceeded $150,000, the required baseline would be 110% × $10,000 = $11,000.
The Annualized Income Installment Method (Form 2210, Schedule AI)
The equal-quarter method assumes income arrives evenly, which is rarely true for freelancers. If most of your income lands late in the year, paying one-fourth in April and June can trigger a penalty for those early quarters even though you are fully paid by year end under the annualized method. Form 2210, Schedule AI, lets you compute each payment based only on income actually earned through that quarter. This is especially valuable for consultants with a big fourth-quarter project, authors receiving an advance late in the year, or seasonal businesses.
Seasonal example: Net profit is $0 in Q1–Q3 and $100,000 in Q4. Under the equal method, you would "owe" $3,825 (one-fourth of ~$15,300 SE tax) by April 15 and June 15 on income you had not yet earned, inviting a penalty. Under the annualized method, Q1–Q3 payments can be near zero and the full tax is paid with the Q4 installment, eliminating the early-quarter penalty. The IRS permits this; you just attach Form 2210 to your return.
How the Underpayment Penalty Is Computed
The penalty is figured on Form 2210 using a day-by-day ("regular") method. For each quarter, the IRS compares what you paid to what you should have paid, and charges interest on the shortfall from the due date of that installment to the filing date. The rate is generally the federal short-term rate plus 3%, set quarterly (for recent years it has ranged from about 3% to 8%). The penalty is charged on the underpayment, not on your whole tax bill, so it is usually modest but annoying. Our calculator estimates whether you breach a safe harbor; for the exact dollar penalty, complete Form 2210.
How to Actually Send the Money
- IRS Direct Pay (from a bank account) at IRS.gov — free and immediate confirmation.
- EFTPS (Electronic Federal Tax Payment System) — the official Treasury system, good if you pay business taxes often.
- Form 1040-ES payment vouchers — mailed with a check; the vouchers help you track amounts.
- Debit or credit card through an IRS-approved processor (fees apply).
Always note the tax year and the installment period when paying so the IRS applies the money correctly. Keep confirmation numbers; they are your proof if a payment is ever misapplied.
State Estimated Payments
Most states with an income tax also require quarterly estimates, usually following the same four dates, with their own thresholds (often a smaller dollar amount like $500 or a percentage of prior tax). Nine states have no state income tax — Alaska, Florida, Nevada, New Hampshire (taxing only interest/dividends, being phased out), South Dakota, Tennessee (only interest/dividends), Texas, Washington (with a small business & occupation tax, not an income tax), and Wyoming — so residents there skip state estimates but still owe federal. See our State SE Tax calculator for how state brackets layer on top of federal.
Common Mistakes
- Forgetting the SE tax is part of the bill. New freelancers often estimate only income tax and underpay by the entire 15.3% SE tax.
- Paying equal quarters on lumpy income. Use the annualized method or you may be penalized for early quarters despite being fully paid by year end.
- Missing the 110% rule. High earners who used last year's lower tax as the baseline, but whose prior AGI exceeded $150,000, fall short of the 110% safe harbor.
- Relying on a refund to cover the bill. A prior-year refund is not a payment; you must actually remit each installment by its date.
- Skipping Q4 because you will file early. You may skip the January 15 payment only if you file and pay in full by January 31.
- Not counting W-2 withholding. If you also have a part-time W-2 job, that withholding reduces the estimated amount you must pay separately — but it is treated as paid evenly across quarters unless you use the annualized method.
How This Connects to Your Other Taxes
Your quarterly payments are simply the delivery mechanism for the totals computed by your other calculators. The base Self-Employment Tax calculator gives you the 15.3% SE component; the Retirement Deduction calculator shows how contributions lower your taxable income and thus your annual bill; the Medicare Surtax calculator adds the 0.9% surtax for high earners; and the State SE Tax calculator adds any state layer. Gig workers should first size net profit with the Uber or Upwork calculator, then feed that profit into this page to get the four payment amounts.