To calculate your estimated tax liability, project your total income for the year, subtract deductions and any withholding, apply the current federal tax brackets plus self-employment tax if it applies, subtract credits, and divide the remainder into four quarterly payments. That is the whole calculation. The rest is knowing which numbers to plug in and when the IRS expects the money.
If you expect to owe $1,000 or more after withholdings and credits, the IRS wants those payments spread across the year rather than settled in one lump at filing time.1Internal Revenue Service. Estimated Taxes
Do You Actually Owe Estimated Tax?
The $1,000 threshold catches most freelancers, independent contractors, sole proprietors, partners, and S corporation shareholders, because no employer is pulling tax out of their pay before it lands.1Internal Revenue Service. Estimated Taxes It also picks up anyone with meaningful investment income from dividends, interest, or capital gains. If you have a W-2 job on the side, the tax withheld from that paycheck counts against the threshold, and if it covers your total bill you may not owe estimated tax at all.
Step by Step: Calculating What You Owe
The IRS provides Form 1040-ES with a worksheet that walks through the math. Pull last year’s Form 1040 as a baseline and gather current-year income records: 1099-NEC forms for contract work, 1099-DIV and 1099-INT for investment income, and a profit-and-loss statement if you run a business.1Internal Revenue Service. Estimated Taxes
Project Your Adjusted Gross Income
Add up your expected earnings for the year. From that total, subtract the adjustments the worksheet asks about: the deductible portion of self-employment tax, student loan interest, and contributions to qualifying retirement accounts.2Internal Revenue Service. Form 1040-ES, Estimated Tax for Individuals What’s left is your projected AGI.
Subtract Your Deduction
Take either the standard deduction or your expected itemized deductions, whichever is larger. For 2026, the standard deduction is $16,100 for single filers, $32,200 for married couples filing jointly, and $24,150 for heads of household.3Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 The result is your taxable income.
Apply the 2026 Tax Brackets
Federal income tax is progressive. Each slice of income is taxed at its own rate, so a single filer earning $80,000 does not pay 22% on the whole amount. They pay 10% on the first $12,400, 12% on the next slice up to $50,400, and 22% only on the portion above that.
For 2026, the brackets for single filers are:3Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
- 10% on income up to $12,400
- 12% on $12,401 to $50,400
- 22% on $50,401 to $105,700
- 24% on $105,701 to $201,775
- 32% on $201,776 to $256,225
- 35% on $256,226 to $640,600
- 37% on income over $640,600
For married couples filing jointly, the brackets are roughly doubled. The 10% band covers income up to $24,800, the 12% band runs to $100,800, and the top 37% rate begins above $768,700.3Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
Subtract Credits
Take off any tax credits you expect to claim, such as the Child Tax Credit. The result is your projected income tax for the year.
Add Self-Employment Tax If It Applies
If you work for yourself, income tax is only half the picture. You also owe self-employment tax at a combined rate of 15.3%: 12.4% for Social Security and 2.9% for Medicare.4Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes) Employees split those costs with their employer, but self-employed workers pay both halves.
The Social Security portion applies to net self-employment earnings up to $184,500 for 2026.5Social Security Administration. Contribution and Benefit Base The Medicare portion has no cap. If your net self-employment income exceeds $200,000 (or $250,000 for married couples filing jointly), an Additional Medicare Tax of 0.9% applies on the amount above the threshold.6Internal Revenue Service. Topic No. 560, Additional Medicare Tax
Form 1040-ES has a dedicated section for this calculation. One offset softens the bite: you can deduct the employer-equivalent half of your self-employment tax (7.65%) when figuring your AGI, which lowers your income tax slightly.2Internal Revenue Service. Form 1040-ES, Estimated Tax for Individuals
Subtract Withholding and Divide by Four
Add income tax and self-employment tax together, then subtract any federal tax withholding you expect from a W-2 job or other source. What remains is your estimated tax bill for the year. Divide it by four. That’s each quarterly payment.
If income shifts mid-year because of a new client, a capital gain, or a slowdown, recalculate and adjust the remaining installments. Waiting until the fourth quarter to true things up is possible but leaves you exposed to penalties on the earlier quarters you underpaid.
Safe Harbors That Protect You From Penalties
Your projection doesn’t have to be perfect. You avoid the underpayment penalty if you hit any of these targets: you owe less than $1,000 after withholdings, you paid at least 90% of the current year’s tax, or you paid at least 100% of last year’s tax bill through your installments and withholding.7Internal Revenue Service. Underpayment of Estimated Tax by Individuals Penalty
The prior-year safe harbor is the easiest to plan around because you already know the number. Just pay in what you owed last year, split over four quarters, and you’re covered no matter what the current year looks like.
The 110% Rule for Higher Earners
If your adjusted gross income last year exceeded $150,000 ($75,000 if married filing separately), the prior-year safe harbor rises from 100% to 110%.8Office of the Law Revision Counsel. 26 U.S. Code 6654 – Failure by Individual to Pay Estimated Income Tax This is the most common trap for higher earners. Someone whose income jumped relies on “100% of last year” without realizing their AGI pushed them into the 110% band.
Uneven Income? Use the Annualized Method
Splitting your bill into four equal payments assumes income arrives steadily. Seasonal businesses and anyone who lands a big project in one quarter and nothing the next know that isn’t real life. The annualized income installment method lets you base each payment on what you actually earned in that period.9Internal Revenue Service. Instructions for Form 2210
You complete Schedule AI of Form 2210, which breaks the year into four overlapping periods: January through March, January through May, January through August, and the full year. Each period’s income is annualized (scaled to a full-year equivalent) to determine what your required installment should be. If you use Schedule AI for any period, you must use it for all four.9Internal Revenue Service. Instructions for Form 2210 It’s most useful when your early-year income is much lower than your annual total.
2026 Quarterly Deadlines
Payments are due four times a year, but the schedule isn’t evenly spaced by calendar quarter:2Internal Revenue Service. Form 1040-ES, Estimated Tax for Individuals
- 1st payment: April 15, 2026
- 2nd payment: June 15, 2026
- 3rd payment: September 15, 2026
- 4th payment: January 15, 2027
The gap between the June and September payments is nearly three months, while April to June is only two. A strict “every three months” reminder misses the June deadline. You can skip the January 15, 2027 payment if you file your 2026 return by February 1, 2027 and pay the full remaining balance with it.2Internal Revenue Service. Form 1040-ES, Estimated Tax for Individuals If a due date falls on a weekend or federal holiday, it moves to the next business day.
How to Send the Payment
IRS Direct Pay is the simplest route. It transfers funds from a checking or savings account with no fees and no registration, and you get a confirmation number immediately.10Internal Revenue Service. Direct Pay with Bank Account For business accounts, larger payments, or if you want to schedule installments in advance, the Electronic Federal Tax Payment System (EFTPS) is the better tool, though it requires enrollment ahead of time.11Internal Revenue Service. Tax Time Guide: Use IRS Electronic Payment Options Both are also available through the IRS2Go mobile app.12Internal Revenue Service. IRS2Go Mobile App
Credit and debit card payments go through IRS-approved processors and carry fees. Debit runs about $2.10 to $2.15 per payment. Credit costs 1.75% to 1.85% of the payment, with a $2.50 minimum.13Internal Revenue Service. Pay Your Taxes by Debit or Credit Card or Digital Wallet On a $5,000 quarterly payment, the credit card fee is $87 to $93. If you prefer paper, mail a check or money order with the voucher from the Form 1040-ES package to the address listed for your state, and keep your bank record as proof since the IRS does not send a receipt.
What Underpayment Costs
The underpayment penalty works like interest on the shortfall for each day it remains unpaid. The IRS sets the rate quarterly at the federal short-term rate plus three percentage points. For the first quarter of 2026, the rate is 7%, compounding daily.14Internal Revenue Service. Revenue Ruling 25-22, Determination of Rate of Interest It resets each quarter, so a full-year underpayment can span several different rates.
Most states with an income tax also require quarterly estimated payments on their own schedule and thresholds, so check your state tax agency’s rules alongside the federal ones.