Independent contractors pay federal taxes on a quarterly schedule, with estimated payments due April 15, June 15, September 15, and January 15 of the following year, and an annual return due April 15. The obligation kicks in once net self-employment earnings reach $400 in a tax year, at which point both income tax and self-employment tax apply.1Office of the Law Revision Counsel. 26 U.S.C. 1402 – Definitions
The Four Quarterly Deadlines
Federal tax runs on a pay-as-you-go basis. Employees have money withheld from every paycheck; contractors handle the equivalent by sending the IRS four estimated payments a year.2Office of the Law Revision Counsel. 26 U.S.C. 6654 – Failure by Individual to Pay Estimated Income Tax The windows the payments cover are not even quarters:
- April 15 covers income earned January 1 through March 31.
- June 15 covers April 1 through May 31, a two-month window.
- September 15 covers June 1 through August 31.
- January 15 of the following year covers September 1 through December 31.
If any of these dates falls on a weekend or federal holiday, the deadline moves to the next business day.3Internal Revenue Service. Individuals 2 The June payment tends to catch people out because it arrives only two months after the April one. A calendar reminder for each date is the bare minimum; setting aside a percentage of every client payment as it comes in is more reliable than scrambling four times a year.
When the Obligation Starts: The $400 Threshold
Self-employment tax kicks in the moment net earnings from self-employment reach $400 in a tax year.1Office of the Law Revision Counsel. 26 U.S.C. 1402 – Definitions Net earnings means gross income minus the ordinary business expenses spent to produce it. Whether you also hold a W-2 job is irrelevant to this calculation. If your freelance, consulting, or gig work produces $400 or more in net profit, that income triggers a separate obligation on top of any employer withholding.
The $400 figure has held steady for decades and is not indexed for inflation. It applies per person, not per client. Earning $250 from one client and $200 from another puts you over the line at $450 combined.4Internal Revenue Service. Self-employment tax (Social Security and Medicare taxes)
What Each Payment Has to Cover
Each quarterly payment covers both income tax and self-employment tax for the period. Self-employment tax is the contractor’s version of the Social Security and Medicare contributions employees split with an employer; contractors pay both halves. The combined rate is 15.3%, made up of 12.4% for Social Security and 2.9% for Medicare.5Office of the Law Revision Counsel. 26 U.S.C. 1401 – Rate of Tax The tax applies to 92.35% of net self-employment earnings rather than the full amount.6Internal Revenue Service. Topic no. 554, Self-employment tax
Form 1040-ES is the IRS worksheet for figuring the totals. It walks through projecting adjusted gross income, subtracting deductions and credits, adding self-employment tax, and arriving at an expected annual liability.7Internal Revenue Service. About Form 1040-ES, Estimated Tax for Individuals Divide that total by four, and each quarterly payment amount falls out.
If income is roughly predictable, last year’s return is the best starting point. First-year contractors, or anyone with a sharp change in income, have to estimate from scratch, and it is safer to err high: overpaying produces a refund at filing, while underpaying produces a penalty. When income swings hard between quarters, the annualized income installment method on Form 2210 allows smaller payments in slow periods and larger ones when work picks up.
How to Avoid the Underpayment Penalty
The IRS charges an underpayment penalty if too little is paid through estimated payments during the year, but three safe harbors protect against it. Meeting any one of them is enough:8Internal Revenue Service. Underpayment of estimated tax by individuals penalty
- The balance due when the annual return is filed, after withholding and credits, is under $1,000.
- Estimated payments and withholding cover at least 90% of the tax on the current-year return.
- Total payments equal or exceed the tax shown on the prior-year return.
That last figure rises to 110% of the prior-year tax if adjusted gross income exceeded $150,000 in the prior year, or $75,000 for married filing separately.9Internal Revenue Service. Publication 505 (2025), Tax Withholding and Estimated Tax A contractor whose prior-year tax was $30,000 and whose AGI cleared $150,000 needs to send in $33,000 across the four installments to sit inside the safe harbor.
The prior-year safe harbor is especially useful during a growing year. Even if the current-year liability comes in far higher, hitting the prior-year threshold blocks the penalty. The remaining balance still comes due at filing, but without the extra charge.
How to Send the Payment
Once the amount is set, there are several ways to get the money to the IRS.
IRS Direct Pay is the simplest option for most people. It is free, needs no registration, moves money directly from a checking or savings account, and issues a confirmation number immediately.10Internal Revenue Service. Direct Pay help It does not schedule recurring payments far in advance.
EFTPS, the Electronic Federal Tax Payment System, suits contractors who want to schedule payments ahead of time and keep payment history in one place. Enrollment requires a PIN mailed within five to seven business days after signup.11U.S. Department of the Treasury. Electronic Federal Tax Payment System (EFTPS)
Credit and debit card payments run through IRS-approved third-party processors. Personal credit card fees run between 1.75% and 1.85% of the payment amount, and commercial card fees can approach 3%.12Internal Revenue Service. Pay your taxes by debit or credit card or digital wallet Unless card rewards cover the fee, this is an expensive route.
Checks and money orders remain an option. Make the check payable to “United States Treasury,” write your Social Security number and “2026 Form 1040-ES” on it, and mail it with the correct voucher from Form 1040-ES to the address for your region.13Internal Revenue Service. 2026 Form 1040-ES Estimated Tax for Individuals Paper payments take weeks to process, so mail early.
The Annual Return Still Comes Due April 15
Quarterly payments do not replace an annual return. By April 15, Form 1040 is due along with two attachments: Schedule C, which reports business income and expenses, and Schedule SE, which calculates self-employment tax. The estimated payments already sent in are credited against the total liability on the return, and the difference is either owed or refunded.
Schedule C is where business deductions actually get claimed. Every dollar of legitimate expense recorded there reduces both the income tax and the self-employment tax base. Contractors who track expenses steadily through the year file straightforwardly at this stage; those who guess almost always overpay.
What Happens If You Miss a Deadline
Missing a quarterly payment does not trigger an immediate notice. The IRS calculates the underpayment penalty when the annual return is filed, based on how much was short, how long it was late, and the prevailing interest rate. For the first quarter of 2026, the IRS underpayment interest rate is 7%, and the rate is reset each quarter.14Internal Revenue Service. Quarterly interest rates
Filing the annual return late is more expensive. The late-filing penalty is 5% of the unpaid tax per month, capped at 25%. The late-payment penalty is a separate 0.5% per month, also capped at 25%.15Internal Revenue Service. Topic no. 653, IRS notices and bills, penalties and interest charges If the full balance cannot be paid, file the return on time anyway. The filing penalty is ten times steeper than the payment penalty, and the IRS offers installment agreements for balances that cannot be covered right away.
The IRS does waive underpayment penalties in limited cases. Retirement after age 62 or disability arising during the tax year or the year before, when the underpayment was for reasonable cause, supports a waiver request on Form 2210. So does a federally declared disaster, and in many disaster cases the IRS applies relief automatically without a form.16Internal Revenue Service. 2025 Instructions for Form 2210 – Underpayment of Estimated Tax by Individuals, Estates, and Trusts