Estimated Taxes for Owners: A Quarterly Cash Calendar for 2025

Nobody mails you a reminder that tax is due four times a year. The schedule is real anyway, and a late or short payment can bring a penalty on top of the tax.

If you earn money from your own business, April is not the only date that matters. Treat the quarterly dates as part of your cash flow, and a strong year stays a strong year. Ignore them, and the bill arrives all at once, usually when the cash is already spoken for. The tax calendar is a cash calendar.

Educational content, not financial, tax, legal or investment advice. Talk to a licensed professional about your situation.

Who has to pay estimated taxes?

The IRS says estimated tax is the method used to pay tax on income that is not subject to withholding, for example earnings from self-employment, interest, dividends and rents.¹

Individuals, including sole proprietors, partners and S corporation shareholders, generally must make estimated payments if they expect to owe $1,000 or more.² The 1040-ES general rule adds a second test: your withholding and refundable credits must be less than the smaller of 90% of your 2025 tax or 100% of your 2024 tax.¹

When you may not need to

If you were a US citizen or resident for all of 2024 and had no tax liability for the full year, the IRS says you do not have to pay estimated tax for 2025.¹ If you also have a job with wages, increasing your withholding on a Form W-4 may let you avoid estimated payments on the other income.¹ An S corporation owner paid on a W-2 can sometimes handle part of the bill that way, which is a question for a CPA.

What are the 2025 due dates?

You can pay all of your estimated tax by April 15, 2025, or in four equal amounts by these dates.¹

If you mail a payment, the postmark counts as the date of payment.¹ The fourth payment is not required if you file your 2025 return by February 2, 2026 and pay the entire balance with it.¹

How much do you have to pay to avoid a penalty?

The IRS describes the common safe harbor this way: most taxpayers avoid the penalty if they pay at least 90% of the tax for the current year, or 100% of the tax shown on the prior year's return, whichever is smaller.³ The penalty generally does not apply if you owe less than $1,000 after withholding and refundable credits.³

The higher-income rule

If your adjusted gross income for 2024 was more than $150,000, you substitute 110% of your 2024 tax for the 100% test.¹

A made-up example

Say your prior-year tax was $18,000. This is an illustration, not a prediction for your business.

The arithmetic: 100% is $18,000, so $4,500 a quarter. 110% is $19,800, so $4,950 a quarter.

Here is the part owners miss. A safe harbor protects you from the underpayment penalty. It does not shrink your actual tax. If this year is much bigger than last year, you still owe the difference when you file. Your cash plan has to cover that, not just the quarterly checks.

What if your income is uneven?

Many online owners earn in bursts. A launch month can put more income in one quarter than the other three combined.

The IRS says that if your income arrives unevenly, you may be able to vary the amounts of your payments to avoid or lower the penalty.³ The annualized income installment method can lower or eliminate the required payment for one or more periods, and if you use it, you file Form 2210 including Schedule AI.¹

How do you build the cash side?

The system is simple. Doing it every time is the hard part.

If the cash timing is the weak part of your business, run the cash runway math first. A tax account that is always raided is not a tax account.

Mistakes that cost owners money

• Waiting until April to think about it. The dates start in the spring.
• Ignoring state taxes. Your state may have its own schedule. Ask your CPA.
• Treating the tax account as a reserve. Tax money and emergency money are different buckets.
• Not updating after a big quarter. A launch changes the math. Recalculate when the income changes, not when the calendar says so.

Graham Stephan gave blunt timing advice in a tax video he posted on January 17, 2024 (the video is sponsored by Rocket Money):

He means early in the year, not in March. The quarterly dates are one more reason to have that conversation before the first payment is due.

What should you check in the third quarter?

A September checkpoint beats a December panic.

Compare year-to-date profit with your plan

If you are running well ahead, your safe harbor payment may leave a large balance due in April. Add to the tax account now, while you can see it coming.

Look at the levers that still exist

A SEP can be set up and funded as late as the due date of your return for the year, including extensions.⁴ That makes the year's contribution decision a spring one, not just a December one. For how it compares with a Solo 401(k), read the Solo 401(k) vs SEP IRA breakdown. Which levers fit your situation is a question for a CPA before December 31.

Taxes are the first claim on every good year. My grandmother's question, So what's your retirement plan?, is the second, and it only gets answered with what is left. Paying the first on time is how you protect the second.

More on keeping money outside the business is in Investing and Retirement.

Keep building.Ekai