Self-employed workers pay Social Security through quarterly estimated taxes

If you work for yourself, you pay Social Security tax directly to the IRS instead of having an employer withhold it from your paycheck. You do this by sending estimated tax payments four times a year — roughly every three months — rather than waiting until tax day. The IRS expects these payments by specific dates, and paying late can result in penalties even if you end up owing nothing when you file your full return.

The amount you owe depends on your net self-employment income (what you earn minus legitimate business expenses). You calculate this yourself using IRS Form 1040-ES, which walks you through the math and tells you how much to send with each quarterly payment. The form is free and available on the IRS website.

Key Takeaways

  • Self-employed workers send estimated tax payments to the IRS four times per year on April 15, June 15, September 15, and January 15.
  • You calculate what you owe using IRS Form 1040-ES, which accounts for your net business income and estimates your total tax liability for the year.
  • You can pay online through IRS Direct Pay, by phone, by mail, or through an accountant or tax software — the IRS accepts multiple methods.
  • Underpaying estimated taxes can result in penalties and interest, even if you have enough withheld overall to cover your final bill.
  • If your income changes significantly during the year, you can recalculate and adjust your remaining payments rather than overpaying.

The four payment dates and how to calculate each one

The IRS sets four fixed dates for estimated tax payments. The first quarter payment (covering January through March income) is due April 15. The second quarter payment (April through May) is due June 15. The third quarter payment (June through August) is due September 15. The fourth quarter payment (September through December) is due January 15 of the following year. If any of these dates falls on a weekend or federal holiday, the deadline moves to the next business day.

To figure out how much to send each quarter, use IRS Form 1040-ES. The form includes a worksheet where you estimate your total net self-employment income for the year, subtract deductions you expect to claim, and calculate your total federal income tax and self-employment tax liability. You then divide that total by four to get your quarterly payment amount. If you expect your income to be uneven across the year — for example, if you earn most of your money in summer — you can calculate each quarter separately and pay different amounts rather than splitting evenly.

Many self-employed workers use tax software or hire an accountant to handle this calculation, especially if their business is complex or their income fluctuates. The software or accountant can also track your payments and alert you before each deadline.

Payment methods the IRS accepts

IRS Direct Pay is the fastest and most direct option. You go to irs.gov, enter your payment information, and the IRS withdraws the money from your bank account on the date you specify. There is no fee, and you get a confirmation number immediately. You can pay this way even if you do not file taxes electronically.

Credit or debit card payments are also available through approved payment processors listed on the IRS website. These processors charge a convenience fee (usually 1.87% to 2.35% of the payment), so you pay more than you would with Direct Pay, but some people use cards to earn rewards or to time the payment differently from their bank account.

Mail payments require you to fill out a voucher (Form 1040-ES) and send a check or money order to the IRS address listed in the form instructions. Mail is slower and riskier — if your payment arrives late, the postmark date matters, so send it well before the deadline. Phone payments are available by calling the IRS at 1-800-829-1040, though this method is less common and you will need to provide banking information over the phone.

If you use a tax professional or accounting software, they often submit payments on your behalf through their own systems. Ask whether they charge a fee for this service.

What happens if you underpay or miss a deadline

The IRS charges penalties and interest if your estimated payments fall short of what you owe. The penalty is calculated as a percentage of the underpayment and compounds daily. Interest is added on top of the penalty. Even if you ultimately owe nothing when you file your full return (because you had other income or large deductions), you can still owe penalties for underpaying during the year.

There is a safe harbor: if you pay at least 90% of your current year's tax liability through estimated payments and withholding, or 100% of the prior year's liability (110% if your prior year income was over $150,000), you generally will not owe penalties. This means if you are unsure of your income, you can base your payments on last year's return and avoid penalties, even if this year turns out to be higher.

If you miss a payment deadline entirely, contact the IRS as soon as you realize it. Paying late is better than not paying at all — the penalty for late payment is smaller than the penalty for non-payment. You can also request a penalty waiver if you have reasonable cause (for example, a serious illness or a natural disaster), though the IRS evaluates these requests case by case.

Adjusting payments if your income changes mid-year

You do not have to stick with the same payment amount all year. If your business earns significantly more or less than you expected when you made your first payment, you can recalculate using Form 1040-ES and adjust your remaining quarterly payments. This is especially useful if you have a seasonal business or if a major client signs on or drops off mid-year.

To adjust, recalculate your total expected income for the full year, subtract your expected deductions, and divide by four. If this new amount is higher than what you have been paying, increase your remaining payments. If it is lower, you can reduce them. Some people recalculate after each quarter to stay as accurate as possible; others adjust only if the change is substantial.

Recalculating does not change your prior payments — you cannot go back and reduce what you already sent. But it can help you avoid overpaying significantly or underpaying and facing penalties.

Tracking payments and keeping records

Keep a record of every estimated tax payment you make, including the date, amount, and confirmation number (if you paid online). The IRS sends you a notice if your payments do not match their records, and having documentation helps you resolve discrepancies quickly. If you pay by mail, keep a copy of the cancelled check or money order receipt.

When you file your annual tax return (Form 1040), you report all estimated payments you made during the year. The IRS matches this against their records. If you overpaid, you can request a refund or have the overpayment applied to next year's estimated taxes. If you underpaid, you owe the difference plus any applicable penalties and interest.

Tax software and accounting firms typically maintain these records for you and include them automatically on your return. If you pay on your own, set a reminder after each payment to file the confirmation away.

Frequently Asked Questions

What if I have a job and also do freelance work on the side?

You pay estimated taxes only on the self-employment income, not on wages from your job (your employer already withholds those). However, if your job withholding is high enough to cover both your job taxes and your self-employment taxes, you may not need to make separate estimated payments. Use Form 1040-ES to calculate whether you need to pay quarterly or whether your job withholding is sufficient.

Can I pay estimated taxes monthly instead of quarterly?

The IRS requires quarterly payments on the four specific dates listed above. You cannot split them into monthly payments. However, you can pay more than the required amount at any time, and you can make extra payments between quarters if you want to reduce your final bill or build a cushion.

What if I did not know I needed to pay estimated taxes until after the deadline?

Pay as soon as you realize the mistake. Late payments incur penalties, but not paying at all incurs larger penalties. When you file your annual return, report all the payments you made (even late ones) and the IRS will calculate the penalties owed. You can also request a penalty waiver if you have a reasonable explanation for the delay.

Do I need to file quarterly tax returns, or just make payments?

You make payments only — no quarterly returns are required. You file one annual tax return (Form 1040) after the year ends, and you report all estimated payments you made on that return. The IRS matches your reported payments against their records.

What if my business loses money one year?

If your net self-employment income is zero or negative, you may owe no estimated taxes for that year. Use Form 1040-ES to calculate — if the result is zero, you do not need to make quarterly payments. However, you still file an annual return to report the loss, which can offset other income or carry forward to future years.