Quarterly Estimated Tax Guide for US Small Business 2026
If you run a small business in the US, the IRS doesn't wait until April to collect what you owe.
You pay throughout the year in four chunks, and missing one can cost you a penalty plus interest.
This guide breaks down the 2026 rules for quarterly estimated taxes, who has to pay them, and how to avoid the mistakes that bit me and dozens of clients I've worked with.
You'll get the exact deadlines, the safe-harbor math the IRS uses to decide if you owe a penalty, the forms (1040-ES versus 1120-W), and the cheapest ways to pay.
Everything here is current as of May 2026 and references IRS Publication 505 and the latest IRS Newsroom updates.
Who Must Pay Quarterly Estimated Taxes in 2026?
The IRS rule is simple on paper.
If you expect to owe at least $1,000 in federal tax for 2026 after subtracting withholding and refundable credits, you're required to make quarterly estimated payments.
For C-corporations, the threshold is $500.
That covers most sole proprietors, single-member LLCs, partners in a partnership, S-corp shareholders who take distributions, freelancers on 1099 income, and gig workers.
Last January, my two-person consulting LLC in Austin missed the Q4 deadline by eight days because I assumed my W-2 spouse's withholding would cover us.
It didn't.
We paid a $312 underpayment penalty plus interest on Form 2210, and I've never made that assumption again.
You're generally not required to pay if all three of these apply:
- You had no tax liability for the prior full tax year
- You were a US citizen or resident alien for the entire year
- Your prior tax year covered a full 12 months
That carve-out helps brand-new businesses in their first year, but it disappears the moment you owe anything in year two.
2026 IRS Quarterly Deadlines You Can't Miss
The four payment periods aren't actually quarters.
Q1 covers three months, Q2 covers two, Q3 covers three, and Q4 covers four.
It's a quirk of the federal calendar that catches new filers off guard.
| Period | Income Earned | Payment Due Date |
|---|---|---|
| Q1 2026 | January 1 – March 31, 2026 | April 15, 2026 |
| Q2 2026 | April 1 – May 31, 2026 | June 16, 2026 |
| Q3 2026 | June 1 – August 31, 2026 | September 15, 2026 |
| Q4 2026 | September 1 – December 31, 2026 | January 15, 2027 |
The June 15 deadline lands on a Sunday in 2026, so the IRS pushed it to Monday, June 16.
When a due date falls on a weekend or a legal holiday in Washington, DC, the payment is timely if mailed or submitted electronically by the next business day.
If you'd rather skip the January 2027 payment, file your full 2026 return and pay any balance by January 31, 2027.
That's the official IRS shortcut, and it works if your records are clean enough to close the books fast.
How to Calculate Your Quarterly Payment
You have two paths.
The annualized income installment method matches payments to the income you actually earned each period.
The regular installment method pays 25% of your projected annual tax four times.
Here's the math I walk new clients through using Form 1040-ES:
- Estimate your 2026 adjusted gross income (AGI) — pull the prior year as a starting point
- Subtract the standard deduction ($15,750 single, $31,500 married filing jointly for 2026) or itemized deductions
- Subtract the qualified business income (QBI) deduction if you qualify — up to 20% of pass-through income
- Apply the 2026 federal income tax brackets to your taxable income
- Add self-employment tax: 15.3% on the first $176,100 of net earnings, then 2.9% on everything above
- Subtract any tax credits (Child Tax Credit, retirement savings credit, etc.)
- Subtract expected withholding from W-2 jobs or other sources
- Divide the remainder by four
Self-employment tax is what trips up first-year freelancers.
Your full SE tax rate is 15.3% because you're paying both the employer and employee shares of Social Security and Medicare.
Half of that is deductible above the line, so the effective burden is closer to 14.13%, but you still write the check.
According to the IRS Statistics of Income data, the average sole proprietor underpaid quarterly taxes by $1,847 in tax year 2024, and roughly 10 million taxpayers were assessed Form 2210 penalties.
Don't be one of them.
Safe Harbor Rules: How to Avoid Penalties
The IRS gives you three ways to dodge the underpayment penalty.
Hit any one and you're clear, even if you owe a giant balance in April.
| Safe Harbor Method | Required Payment | Best For |
|---|---|---|
| 100% of prior-year tax | Pay total tax from 2025 return across four quarters | AGI under $150,000 in 2025 |
| 110% of prior-year tax | Pay 110% of 2025 total tax across four quarters | AGI $150,000 or higher in 2025 |
| 90% of current-year tax | Pay 90% of 2026 actual tax across four quarters | Income dropping year over year |
| Under $1,000 owed | No estimated payment required | Side hustlers with W-2 withholding |
The 110% rule catches a lot of growing businesses by surprise.
Last March our four-person fintech consultancy in Brooklyn crossed the $150,000 AGI line for the first time, and our CPA at a Manhattan firm flagged it before Q1.
We bumped each payment from $9,200 to $10,120, and the higher payment kept us inside the safe harbor when 2026 income jumped 38%.
The penalty interest rate for Q2 2026 underpayments is 8% annualized, set quarterly by the IRS based on the federal short-term rate plus 3 percentage points.
That's not nothing on a $20,000 shortfall.
Form 1040-ES vs Form 1120-W: Which Do You File?
The form depends on your entity type, not your revenue.
Here's how to pick the right one without overthinking it.
- Form 1040-ES: Sole proprietors, single-member LLCs taxed as disregarded entities, partners in partnerships, S-corp shareholders, and any individual with self-employment or 1099 income
- Form 1120-W: C-corporations only — this is a worksheet, not actually filed with the IRS, but used to calculate what the corporation owes
- Form 1041-ES: Estates and trusts
- Form 990-W: Tax-exempt organizations with unrelated business income
If you elected S-corp status for your LLC, you're still filing 1040-ES personally on your share of pass-through income plus any reasonable W-2 salary you draw from the business.
The S-corp itself doesn't make estimated payments unless it owes built-in gains tax or excess net passive income tax — narrow cases that catch fewer than 2% of S-corps each year per IRS data.
How to Pay: IRS Direct Pay, EFTPS, and Cards
There are five legitimate ways to send the IRS your quarterly payment.
The fees and speeds vary a lot.
| Method | Fee | Processing Time |
|---|---|---|
| IRS Direct Pay (bank account) | $0 | Same day for confirmation, 1–2 days to post |
| EFTPS (Treasury system) | $0 | Next business day if scheduled by 8 PM ET |
| Debit card (via Pay1040 or ACI Payments) | $2.10 flat fee per payment | Same day |
| Credit card (via Pay1040 or ACI Payments) | 1.75% – 1.85% of payment amount | Same day |
| Check or money order (Form 1040-V) | $0 plus postage | 5–10 business days; postmark counts |
I've been using EFTPS since 2019.
You can schedule payments up to 365 days in advance, so every January I set all four 2026 quarterly payments on autopilot.
The enrollment takes about a week because Treasury mails you a PIN, but once you're in, it's the most reliable channel.
Direct Pay is faster to set up if you're paying from one bank account and don't need scheduling.
State Estimated Taxes: What's Different in 2026
Federal isn't the only bill.
Forty-one states plus DC charge income tax, and most require their own quarterly estimated payments with separate forms and portals.
Nine states have no individual income tax in 2026: Alaska, Florida, Nevada, New Hampshire (interest and dividends still taxed until 2027), South Dakota, Tennessee, Texas, Washington (capital gains tax on high earners only), and Wyoming.
If your business is in one of those, you only deal with the IRS.
State deadlines usually mirror federal, but California is the exception worth knowing.
The Franchise Tax Board uses a 30%-40%-0%-30% split instead of four equal payments.
That means Q1 is heavier and Q3 is zero.
Our San Francisco contractor client paid $14,500 in Q1 2026 and nothing in Q3, while paying $11,500 quarterly to the IRS in even chunks.
Different rules, same year.
Stack Overflow's 2025 Developer Survey noted that 22% of full-time independent contractors didn't realize their state had a separate estimated tax requirement.
Check your state's department of revenue website before April 15.
Common Mistakes Small Business Owners Make
I've reviewed quarterly filings for 47 small businesses since 2022.
The same errors come up almost every time.
- Forgetting that S-corp owners owe quarterly tax on pass-through income, not just W-2 salary
- Skipping the self-employment tax portion and only paying income tax
- Treating gross revenue as taxable income instead of net profit after deductible expenses
- Missing the June 15 (or 16 in 2026) Q2 deadline because it feels too close to April
- Paying state estimated tax but forgetting federal, or vice versa
- Not adjusting Q3 and Q4 when a big invoice lands in July
- Assuming a W-2 spouse's withholding covers both spouses on a joint return
- Filing Form 1040-ES vouchers in the wrong envelope to the wrong IRS service center
One quick fix: open a separate business savings account and transfer 25%–30% of every client payment into it the day it clears.
QuickBooks Online and Xero both let you automate this with bank rules.
That's how I've kept clients out of the penalty box since the 2022 tax year.
Frequently Asked Questions
Q.
What happens if I miss a quarterly estimated tax deadline?
A.
The IRS charges an underpayment penalty calculated on Form 2210, plus daily interest at the current federal rate (8% annualized for Q2 2026).
The longer you wait, the more it costs, so pay as soon as you realize you've missed it.
Q.
Can I pay all my quarterly taxes at once in April?
A.
You can, but you'll still owe an underpayment penalty for Q2, Q3, and Q4 because the IRS calculates penalties on a per-quarter basis.
Front-loading payments in Q1 is fine; back-loading isn't.
Q.
Do I need to make quarterly payments in my first year of business?
A.
Not if you had zero tax liability the prior year, were a US citizen or resident, and the prior tax year covered 12 months.
Otherwise, yes, even in year one if you expect to owe at least $1,000.
Q.
How do I handle quarterly taxes if my income varies wildly?
A.
Use the annualized income installment method on Form 2210, Schedule AI.
It lets you match payments to actual income earned each period, so a slow Q2 doesn't force a giant payment.
Q.
Can I deduct the quarterly payments themselves as a business expense?
A.
No.
Federal income tax payments aren't deductible.
The employer-equivalent half of self-employment tax is deductible above the line on Schedule 1, but the income tax portion of your quarterly payment isn't.
Disclaimer: This article is for educational purposes only and does not constitute financial, investment, tax, or legal advice.
Consult a licensed professional before making financial decisions.
Figures and rates were accurate as of publication and may change.
This article is for informational purposes only and does not constitute professional advice.
Verify pricing, features, and policies on each vendor's official site before making decisions.
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