Quarterly estimated taxes for side income

Updated October 2026 · 2026 tax year · 7 minute read

Taxes on side income are not withheld, so the IRS expects you to pay them during the year in installments. These are called estimated taxes. This guide covers who needs to pay, the 2026 due dates, how much to pay, and how to catch up if you have already missed a date.

Who has to make estimated payments

The IRS says individuals generally must make estimated tax payments if they expect to owe $1,000 or more when they file their return, after subtracting withholding and credits. If you have a regular job and a modest side income, you may be able to avoid the whole process by increasing the withholding at work instead (more on that below).

2026 due dates

The year is divided into four payment periods. For the 2026 tax year the due dates are:

The periods are uneven, which is why the second payment arrives only two months after the first. If a date falls on a weekend or legal holiday, the deadline moves to the next business day. Schedule electronic payments to go out a day or two before the deadline rather than on it, so a glitch does not turn into a late payment.

How much to pay

The simplest approach is to pay one quarter of the amount you have estimated you will owe for the year. Our calculator shows that figure as "Each quarter".

The IRS will not charge an underpayment penalty if you pay enough by each due date to meet one of these safe harbors:

• 90% of this year's tax, or
• 100% of last year's tax, as shown on last year's return. If your adjusted gross income last year was more than $150,000 ($75,000 if married filing separately), the prior-year figure rises to 110%.

The prior-year option is useful when your side income is growing. If your total tax last year was $9,000 and your income is under the $150,000 line, paying $9,000 across the four installments generally protects you from a penalty even if this year's bill turns out to be larger. You would still owe the difference when you file; the safe harbor only avoids the penalty.

An alternative: raise your paycheck withholding

If you have a regular job, you can submit a new Form W-4 to your employer and ask for extra tax to be withheld from each paycheck (Step 4(c)). Withholding generally counts as if it were paid evenly through the year, regardless of when it was actually taken out, which makes it a forgiving way to cover a shortfall that you only notice late in the year. It removes the need to remember four dates, but you have to estimate the right extra amount per paycheck yourself.

How to pay

• IRS Direct Pay. Pay directly from a checking or savings account, with no fee, through the IRS website or app.
• Your IRS online account. You can also pay and see your payment history there.
• EFTPS. The Electronic Federal Tax Payment System lets you schedule payments in advance.
• By mail. Send a check with a Form 1040-ES payment voucher. Mailed payments are judged by postmark date.
• Debit or credit card. Available through IRS-approved payment processors, which charge a fee.

Whichever method you use, save the confirmation. You will report the total of your estimated payments on your tax return, and a record is what you need if a payment is ever misapplied.

What if you missed a payment?

Pay as soon as you can. The underpayment penalty is figured separately for each payment period and grows with the time a shortfall stays unpaid, so a late payment costs less than not paying. For 2026, if you have missed the earlier dates, your next opportunity is the January 15, 2027 payment, and you can pay more than a quarter's share at that point to catch up. The IRS says you can pay weekly, monthly, or on any schedule you like, as long as enough has been paid in by each due date. The final penalty, if any, is calculated on Form 2210 when you file.

If your income is uneven

Side income is often lumpy. Someone who earns most of their money in November would be treated as underpaying early in the year under the standard rules. The IRS offers an annualized income installment method, claimed on Form 2210, that can lower or remove the penalty in that situation. It takes more work, so it is worth raising with a tax professional if your income is very seasonal.

Don't forget your state

Federal estimated payments cover federal tax only. If your state taxes income, you will likely have separate state estimated payments, with their own forms and sometimes their own schedule. California, for example, weights its installments 30%, 40%, 0% and 30% rather than splitting them evenly. Check your state revenue department's website, or read our state income tax guide.

Run the numbers with the free calculator

This guide is general information, not tax advice. Deadlines and rules can change, and exceptions apply to farmers, fishers, and some other taxpayers. Confirm the details for your situation with the IRS or a tax professional.