How Founders Can Handle Quarterly Taxes with Confidence

When you work for yourself, no employer withholds taxes from your pay. The IRS expects you to handle that yourself — 4 times a year. This guide covers what quarterly estimated taxes are, when they're due, how to calculate what you owe, how to pay, and how to avoid underpayment penalties.

Quarterly taxes are estimated tax payments you make to the IRS 4 times a year to cover income you earn without withholding. When you're self-employed or running a business, no employer pulls taxes from your pay — so the IRS requires you to pay as you go. These payments cover 2 things: federal income tax and self-employment tax.

Self-employment tax covers your Social Security and Medicare contributions — the same taxes an employer would split with you if you were on payroll. The self-employment tax rate is 15.3%: 12.4% for Social Security and 2.9% for Medicare. You pay it on top of your regular income tax, which is why the quarterly payment can feel larger than people expect.

The IRS requires quarterly estimated payments if you expect to owe at least $1,000 in federal taxes for the year after subtracting any withholding and refundable credits. If you're below that threshold, you don't need to pay quarterly — but most founders running a profitable business will clear it.

The IRS sets 4 estimated tax due dates each year. They don't follow a perfectly even 3-month split — the second quarter covers only 2 months — so it's worth putting all 4 dates on your calendar now rather than assuming they're evenly spaced.

• April 15 — covers income earned January 1 through March 31

• June 15 — covers income earned April 1 through May 31

• September 15 — covers income earned June 1 through August 31

• January 15 of the following year — covers income earned September 1 through December 31

If a due date falls on a weekend or federal holiday, the deadline moves to the next business day. Set calendar reminders at least a week before each date — payments need to post by the deadline, not just be initiated.

To figure out your quarterly payment, estimate your total income for the year, subtract your business deductions, calculate the tax owed on that net amount using your tax bracket, add self-employment tax at 15.3%, then divide the total by 4. The IRS provides Form 1040-ES — which includes a worksheet — to walk through this calculation.

If your income varies month to month, estimating the full year can feel like guesswork. The safest approach for most founders is to use last year's tax bill as a baseline. Pay 100% of what you owed last year in equal quarterly installments — or 110% if your adjusted gross income exceeded $150,000 — and the IRS won't assess an underpayment penalty even if you end up owing more at filing time. This is called the safe harbor rule.

A practical way to stay ahead: set aside 25–30% of every payment you receive into a separate savings account. That buffer covers both income tax and self-employment tax for most founders in the early years, and it keeps the quarterly payment from feeling like a surprise.

The IRS offers several ways to pay estimated taxes. Online options are faster, give you an instant confirmation, and eliminate the risk of a check getting lost in the mail. Here are your main options.

IRS Direct Pay

IRS Direct Pay lets you pay directly from a checking or savings account at no cost. No registration required. Go to irs.gov/payments, select "Estimated Tax" as the reason, and follow the prompts. You'll get a confirmation number immediately. This is the most straightforward option for most founders.

Electronic Federal Tax Payment System (EFTPS)

EFTPS requires a one-time enrollment but lets you schedule payments in advance — useful if you want to set all 4 quarterly payments at the start of the year and not think about them again. Enrollment takes a few days to process, so set it up before your first deadline.

Debit or credit card

You can pay by debit or credit card through IRS-approved processors, but a processing fee applies — typically around 1.85–1.99% for credit cards and a flat fee for debit. It's a valid option if cash flow is tight around a deadline, but the fee adds up over 4 quarters.

Mail with Form 1040-ES voucher

You can mail a check with the Form 1040-ES payment voucher to the IRS address for your location. This works, but it's slower and gives you no instant confirmation. If you go this route, mail at least a week before the deadline and keep a copy of the check.

If you don't pay enough in estimated taxes by each quarterly deadline, the IRS charges an underpayment penalty — calculated quarterly based on the federal short-term interest rate plus 3 percentage points, compounded daily. Missing a quarter doesn't just affect your annual filing; the penalty accrues from the missed due date forward.

There are 3 ways to avoid the penalty entirely. Pay at least 90% of what you'll owe for the current year across your 4 quarterly payments. Or pay 100% of what you owed last year — 110% if your adjusted gross income exceeded $150,000. Or owe less than $1,000 total after subtracting withholding and credits when you file. Meeting any one of these thresholds protects you.

The safe harbor based on last year's tax bill is the most reliable option when your income is unpredictable. You know exactly what you paid last year — divide it by 4, pay that amount each quarter, and you won't owe a penalty regardless of how this year turns out. A tax professional can help you figure out which threshold makes the most sense for your situation.

Quarterly taxes get harder when you're scrambling to figure out what you earned 3 months ago. The founders who handle this well aren't doing anything complicated — they're just consistent about a few habits that make each payment straightforward.

Track your income and deductible expenses every month, not just at quarter-end. When payment time comes, you'll have the numbers ready instead of hunting through bank statements. A dedicated business bank account makes this much easier — all your business income and expenses run through one place, and the records are already separated from your personal finances.

• Set aside 25–30% of each payment you receive into a separate savings account earmarked for taxes

• Put all 4 quarterly deadlines on your calendar with a reminder 1 week before each one

• Keep Form 1040-ES bookmarked — the worksheet helps you recalculate if your income changes significantly mid-year

• Save records of every quarterly payment: confirmation numbers from IRS Direct Pay or EFTPS, or copies of mailed checks