If you run your own business and nobody is withholding taxes from your income throughout the year, the IRS does not wait until April to collect. It expects you to pay as you go, four times a year. For most founders and self-employed business owners, quarterly estimated taxes are not optional. They are a legal requirement, and missing them comes with a penalty even if you pay everything you owe by the end of the year.
Here is what you need to know.
The short answer: mandatory if you expect to owe $1,000 or more
The IRS requires quarterly estimated tax payments if you expect to owe at least $1,000 in federal tax after withholding and refundable credits. For corporations, the threshold is $500 at the entity level.
This applies to anyone whose income is not fully covered by withholding during the year, which includes most founders, freelancers, and self-employed professionals. If you have a W2 job alongside your business, the withholding from that job may offset some or all of your obligation, but you need to run the numbers rather than assume.
How it works by business structure
The obligation differs depending on how your business is set up:
- Sole proprietors and single-member LLC owners: business income flows to your personal return; estimated payments are made by you personally on a quarterly basis
- Multi-member LLCs and partnerships: the entity does not pay federal income tax itself, but each partner or member may need to make estimated payments on their share of the income
- S-Corp shareholders: the corporation runs payroll and withholds on your salary, but if you also take distributions or have pass-through income that withholding does not cover, you may still owe estimated payments
- C-Corps: the corporation itself owes estimated taxes if it expects to owe enough corporate tax at the entity level, separate from any personal obligations of the owners
The safe harbor rules: how to protect yourself from penalties
The IRS safe harbor rules are the most practical tool founders have for managing estimated tax risk. If you meet either of the following thresholds, you are protected from underpayment penalties even if you ultimately owe more:
- Pay at least 90% of your current year tax liability, or
- Pay at least 100% of your prior year tax liability
If your prior year adjusted gross income exceeded $150,000 (or $75,000 if married filing separately), the prior year safe harbor rises to 110%.
For founders with growing or unpredictable income, the prior year safe harbor is often the simpler and safer option. You do not need to project this year’s income accurately; you just need to match last year’s total tax bill, plus 10% if you are above the income threshold.
The 2026 payment deadlines
The four federal estimated tax deadlines for calendar year 2026 are:
For Individuals / Pass-through Entities (S-Corp, Partnerships, LLCs)
Taxes are paid at the owner level, with these due dates:
| Payment | Due date | Covers |
| Q1 | April 15, 2026 | January to March |
| Q2 | June 15, 2026 | April to May |
| Q3 | September 15, 2026 | June to August |
| Q4 | January 15, 2027 | September to December |
The quarters are not evenly spaced. The gap between June and September is only three months, while September to January is four. This catches founders off guard, particularly the September deadline which covers a shorter period than most people expect.
If a deadline falls on a weekend or holiday it moves to the next business day. Payments can be made via IRS Direct Pay, EFTPS, or by check with Form 1040-ES.
For Corporations (C-Corp)
Estimated tax payments are generally due in four installments:
- April 15 – 1st installment
- June 15 – 2nd installment
- September 15 – 3rd installment
- December 15 – 4th installment
(If the due date falls on a weekend or holiday, it shifts to the next business day.)
What happens if you miss a payment
Missing or underpaying triggers an underpayment penalty. It is not a flat fee; it is interest-based and compounds using the IRS statutory interest rate, which changes quarterly. The penalty applies per quarter, so missing multiple payments compounds the exposure.
The safe harbor rules can eliminate the penalty entirely even if you ultimately owe more than you paid. This is worth understanding before you assume the penalty is unavoidable.
If your income is variable or seasonal: there is a better method
Equal quarterly payments do not always make sense for founders whose revenue is uneven or back-loaded. Paying the same amount in April as in September can mean overpaying early and underpaying late, even if the annual total is correct.
The annualized income installment method lets you match payments to when income is actually earned. It requires completing Form 2210 Schedule AI at filing time, which recalculates what each quarterly payment should have been based on actual income per period. It takes more work but can significantly reduce penalties for founders with seasonal or variable revenue.
State estimated taxes: do not forget the other bill
States have their own estimated tax rules, deadlines, and penalties on top of federal requirements. California and New York both have separate frameworks with their own penalty structures, and their deadlines do not always align with federal ones.
If you operate in California or New York, verify your state obligations separately. Relying only on federal guidance is one of the more common and avoidable mistakes founders make.
Common mistakes worth avoiding
- Not realizing estimated taxes are required until a penalty notice arrives
- Assuming your accountant handles the payments automatically without confirming this
- Calculating payments based on gross revenue rather than net taxable income
- Not adjusting payments mid-year when income grows significantly
- Missing the September deadline because it covers a shorter period than other quarters
- Ignoring state estimated tax obligations entirely
Frequently asked questions
Do I have to pay estimated taxes if my business is not yet profitable? If you do not expect to owe at least $1,000 in federal tax after withholding and credits, you are generally not required to make estimated payments. However, if you have any doubt, the safe harbor calculation based on your prior year tax bill is the simplest way to confirm.
What if I overpay my estimated taxes? Overpayments are credited against your final tax bill. If you overpay significantly, you can request a refund when you file your annual return or apply the overpayment to the following year’s estimated taxes.
Can I skip a quarterly payment and just pay more at year end? Technically yes, but the underpayment penalty applies per quarter, not just annually. Paying nothing for three quarters and catching up in Q4 will still result in penalties for the earlier quarters even if the total annual payment is correct.
Does the One Big Beautiful Bill Act change how estimated taxes work? The OBBBA affects the amount of tax you owe but did not create a new estimated tax framework. The core safe harbor rules and thresholds remain the same. You should factor any OBBBA-related changes to your overall tax liability into your quarterly calculations, but the mechanics of how estimated taxes work are unchanged.
Estimated tax planning is one of those things that feels optional until it is not. Every situation is different, and the right approach depends on your business structure, income pattern, and prior year liability. This article is intended as a general guide and should not be relied upon as tax advice for your specific circumstances. If you want to make sure you are calculating correctly and not leaving yourself exposed to penalties, MyTaxFiler can help you work through it.