You can pay capital gains tax early, and for most people with a sizable gain, you’re expected to. The federal system is pay-as-you-go: if you expect to owe $1,000 or more in total tax for the year after withholding and refundable credits, the IRS generally wants that money in quarterly installments rather than a lump sum in April.1Internal Revenue Service. Frequently Asked Questions on Individual Estimated Tax Paying capital gains tax early through estimated payments or extra paycheck withholding is how you avoid the underpayment penalty, which applies even when you eventually pay every dollar owed.
When the Rule Applies to You
Estimated payments are the mechanism for income that isn’t subject to automatic withholding: capital gains, dividends, interest, rent, self-employment earnings. You’re on the hook for them if both of these are true for the current year: you expect to owe at least $1,000 after withholding and refundable credits, and your withholding and credits will cover less than the smaller of 90% of this year’s tax or 100% of last year’s tax. The prior-year figure climbs to 110% if your prior-year adjusted gross income was above $150,000, or above $75,000 if you file married filing separately.1Internal Revenue Service. Frequently Asked Questions on Individual Estimated Tax
If you work a W-2 job with normal withholding and rarely sell investments, this system usually doesn’t touch you. The moment you close on a rental property, cash out a brokerage position, or take a large distribution, it does.
The Four Quarterly Deadlines
The tax year is split into four uneven periods, each with its own due date:2Internal Revenue Service. Individuals – Estimated Tax Payment Deadlines
- January 1 through March 31: payment due April 15
- April 1 through May 31: payment due June 15
- June 1 through August 31: payment due September 15
- September 1 through December 31: payment due January 15 of the following year
Deadlines that fall on a weekend or federal holiday roll to the next business day. The periods aren’t true quarters, which matters when you’re pinning down which window a sale falls into. A closing on June 2 belongs to the third period, not the second.
Safe Harbors: How to Avoid the Penalty Without Guessing Perfectly
You can’t know your final tax bill in April while making payments during the year. The IRS builds in two safe harbors, and hitting either one shuts off the underpayment penalty regardless of what you actually end up owing:1Internal Revenue Service. Frequently Asked Questions on Individual Estimated Tax
- Current-year method: pay at least 90% of the tax due for this year through withholding and estimated payments.
- Prior-year method: pay at least 100% of the total tax on last year’s return, or 110% if your prior-year AGI was above $150,000 ($75,000 if married filing separately).
The prior-year method is the useful one when a big gain lands in your year. Last year’s tax is a fixed, known number. If you owed $30,000 last year and this year you sell a business generating $500,000 in gain, you can pay $30,000 (or $33,000 at the 110% level) in four installments and defer the rest of the tax on that gain until you file. The standard approach is dividing the safe harbor total by four and paying equal installments. Form 1040-ES includes a worksheet for the calculation.3Internal Revenue Service. About Form 1040-ES, Estimated Tax for Individuals
Using Paycheck Withholding Instead
If you have a W-2 job, there’s a cleaner option than the quarterly ritual. File a new Form W-4 with your employer and add an extra dollar amount on Step 4(c). That additional withholding counts toward your total tax payments the same way estimated payments do.4Internal Revenue Service. Estimated Taxes
The advantage is timing. Withholding is treated as paid evenly through the year no matter when your employer actually remitted it.5Internal Revenue Service. Publication 505 – Tax Withholding and Estimated Tax So if you realize in October that a summer sale left you $12,000 short, you can raise withholding on the paychecks left in the year and the IRS treats that catch-up as if it had been spread across all four quarters. The same $12,000 sent as a single late estimated payment would still leave the earlier quarters underpaid and generate a penalty. For a lot of people, this alone solves the problem.
Late-Year Gains and the Annualized Income Method
Equal quarterly payments assume income arrives steadily, and capital gains rarely do. If you sell in November, paying the same amount in April as in January feels off because the gain didn’t exist yet. The annualized income installment method calculates the tax owed for each period based on income actually received through the end of that period.6Internal Revenue Service. Instructions for Form 2210
Under this method, a large December gain only needs to be covered by the January 15 payment. The earlier quarters reflect the lower income you actually had. The cost is complexity: you complete Schedule AI of Form 2210, and once you use it for one quarter you use it for all four. Tax software or a preparer usually earns its fee here.
How to Send the Payment
IRS Direct Pay is the simplest route. It pulls from a checking or savings account, costs nothing, gives you an immediate confirmation number, and lets you modify or cancel within two days of the scheduled date. Individual Direct Pay transactions are capped at $10 million.7Internal Revenue Service. Direct Pay with Bank Account The IRS2Go mobile app also connects to Direct Pay and to card payments through approved processors.8Internal Revenue Service. IRS2Go Mobile App
The Electronic Federal Tax Payment System (EFTPS) has been another option, but the IRS stopped accepting new individual enrollments through EFTPS in October 2025, and all individual taxpayers will need to move to Direct Pay or IRS Online Account by late 2026.9EFTPS. Welcome to EFTPS Online If you’re already enrolled, you can keep using it and schedule payments up to the day before the due date.
Paper still works. Mail a check or money order with the quarter’s voucher from Form 1040-ES. Each voucher is tied to a specific quarter, and sending a payment without the matching voucher risks a processing delay and a bogus underpayment notice.
What the Penalty Actually Costs
If no safe harbor is met and no exception applies, the IRS charges a penalty that behaves like interest on each quarter’s shortfall. The rate is the federal short-term rate plus three percentage points, compounded daily. It ran at 7% for the first quarter of 202610Internal Revenue Service. Interest Rates Remain the Same for the First Quarter of 2026 and dropped to 6% starting in the second quarter.11Internal Revenue Service. Internal Revenue Bulletin 2026-8 The clock runs separately for each quarter, from that quarter’s deadline until you pay or until April 15, whichever comes first.
You don’t have to compute the penalty yourself. File your return, pay the balance, and the IRS will calculate and bill it. Form 2210 comes in only if you want to claim an exception or use the annualized method to reduce the amount.12Internal Revenue Service. Instructions for Form 2210 – Underpayment of Estimated Tax by Individuals, Estates, and Trusts On a routine underpayment of a few thousand dollars, the damage is a few hundred. On a six- or seven-figure gain with nothing paid in during the year, it’s real money.
Narrow Waivers
The IRS can waive the penalty in a few specific situations: federally declared disasters, and cases where the taxpayer retired after reaching age 62 or became disabled during the tax year or the prior year, when the underpayment was due to reasonable cause rather than neglect.12Internal Revenue Service. Instructions for Form 2210 – Underpayment of Estimated Tax by Individuals, Estates, and Trusts You request a waiver by checking the box in Part II of Form 2210 and attaching an explanation. Don’t build a plan around getting one.
Don’t Forget the State
Federal payments aren’t the whole picture. Most states with an income tax also require estimated payments, often on the same schedule, with their own thresholds (some as low as $250 in expected tax owed) and their own separate penalties for missing them. Check your state’s department of revenue before you finalize what to send.