Quarterly Estimated Taxes Explained

The U.S. tax system is pay-as-you-go. W-2 employees pay throughout the year through paycheck withholding. Self-employed people, freelancers, gig workers, and most small business owners are expected to pay through quarterly estimated taxes. Skipping them, or underpaying, triggers an IRS underpayment penalty even if you eventually pay everything in full at year-end.

This is plain-English starter content, not tax advice. For your specific situation, talk to a CPA. For broader context, see our Learn hub and self-employment tax guide.

Who has to pay them

The general rule from the IRS: you owe estimated taxes if you expect to owe $1,000 or more in federal tax for the year after subtracting any withholding and refundable credits. The threshold is $500 for most C corporations.

In practice that includes:

• Sole proprietors and single-member LLC owners with meaningful net profit
• Freelancers and consultants paid on 1099s
• Most gig workers
• Partners in partnerships
• S-corp shareholders on income beyond their W-2 salary
• Anyone with substantial investment income that isn't withheld

The four payment dates

Estimated tax payments are due four times a year, but the deadlines aren't evenly spaced. They cover income earned during these periods:

• Q1: January 1 – March 31 → due around April 15
• Q2: April 1 – May 31 → due around June 15
• Q3: June 1 – August 31 → due around September 15
• Q4: September 1 – December 31 → due around January 15 of the following year

If a date falls on a weekend or federal holiday, it shifts to the next business day. The official current schedule is at the IRS estimated taxes page.

How to figure out the amount

The IRS provides Form 1040-ES, which includes a worksheet to estimate the year's tax. The math involves projecting your annual net business income, adding any other income, applying the standard or itemized deduction, calculating income tax, adding self-employment tax, and subtracting credits.

Two practical shortcuts most small owners use:

The safe-harbor rule

To avoid the underpayment penalty, your total payments (withholding + estimated payments) generally must equal at least one of these:

• 90% of the current year's tax, or
• 100% of last year's tax (110% if last year's adjusted gross income was over $150,000)

Paying the safe-harbor amount means you may still owe a balance in April, but you avoid the underpayment penalty. This is the simplest way to set quarterly amounts: take last year's total federal tax, divide by four, pay that.

The percentage-of-profit shortcut

A common rough estimate for new self-employed people: set aside 25% to 30% of every dollar of net profit in a separate savings account, and use it to pay estimated taxes. Adjust upward if you live in a high-tax state.

How to pay

Three main payment options:

1. IRS Direct Pay — free bank-account payment from irs.gov/payments. Get the confirmation number for your records.
2. EFTPS — Electronic Federal Tax Payment System. Free, but enrollment takes about a week. Common for businesses making payroll deposits as well.
3. Mail Form 1040-ES vouchers with a check. Slowest, but still allowed.

Credit card payment is allowed but the third-party processor fee usually exceeds any rewards.

State estimated taxes

Most states with income tax also require quarterly estimated payments. Deadlines often line up with the federal dates but not always. Each state has its own form, payment portal, and safe-harbor rules. Check your state department of revenue.

Common mistakes

• Treating revenue as take-home. Set the tax cash aside the day it arrives.
• Skipping Q1 because the year is "young." The Q1 payment is due in April, when last year's return is also due — easy to forget.
• Paying once at year-end. Even if you pay your full balance, the IRS charges an underpayment penalty calculated quarterly.
• Forgetting state. State penalties stack on top of federal.
• Not adjusting after a big income change. A surprise large project, big sale, or big windfall changes the math. Recalculate mid-year if needed.

What the underpayment penalty looks like

The IRS underpayment penalty is technically interest, not a flat fine. The rate adjusts quarterly. For example, recent rates have run around 7% to 8% annual, charged for the period each underpayment was outstanding. It is rarely catastrophic for small underpayments but adds up quickly on larger ones.

You can request a waiver in narrow circumstances — disaster declarations, retirement at 62 or older, certain hardship situations — using Form 2210.

A simple system that works

A practical setup most small business owners use:

1. Open a separate "tax" savings account with your business bank.
2. Each time business income lands, transfer a fixed percentage (often 25% to 30%) into the tax account.
3. On each quarterly date, pay federal and state estimated taxes from the tax account using IRS Direct Pay and your state's portal.
4. After your annual return is filed, true up — refund stays in the tax account for next year, or you make a top-up payment.

This separation keeps you from accidentally spending money that isn't yours.

A worked example for a freelance year

Imagine your first year as a self-employed graphic designer. Net profit projection: $48,000. Last year's federal tax (when you were a W-2 employee): $4,200. Numbers are illustrative.

• Safe-harbor option: pay 100% of last year's federal tax — $4,200 spread across four payments of $1,050. This guarantees no underpayment penalty.
• Pay-as-you-go option: project this year's federal income tax + SE tax at roughly $11,000 combined, divided into $2,750 per quarter.
• Hybrid: pay the safe-harbor minimum each quarter, save extra in your tax account, and pay the balance with the April return.

State estimated taxes layer on top. In a state with a 5% income tax, add roughly $2,400 over the year (about $600 per quarter), paid through that state's portal.

What about S-corp owners?

If you elect S-corp taxation, your tax payments split: federal income tax withholding through payroll on your salary, plus quarterly estimated taxes on the additional pass-through income (the K-1 distribution). Many S-corp owners use a higher salary so most of their tax is collected through payroll, then pay smaller estimated payments on the rest. Your CPA usually does this projection at year-end and gives you a quarterly schedule to follow.

A note on the numbers

Tax brackets, safe-harbor thresholds, and underpayment interest rates change every year. Always check the latest at IRS.gov and your state department of revenue. This is general info, not tax advice — talk to a CPA before relying on it for your situation.

Tax laws and SBA programs change every year — always check the latest at IRS.gov, SBA.gov, and your state's Secretary of State website.