Q3 Estimated Taxes Due Soon: How to Calculate and Pay in 2025

The Q3 estimated tax deadline is approaching fast. For 2025, the due date is September 15, 2025. If you earn income without regular withholding—such as freelance work, side hustles, investment income, or small business revenue—you need to make quarterly estimated tax payments to avoid penalties.

This guide walks you through how to calculate your estimated tax 2025, determine what you owe for the third quarter, and the easiest ways to pay IRS online.

When Are Q3 Estimated Taxes Due?

The IRS requires four quarterly estimated payments each year. For 2025, the schedule is:

• Q1: April 15, 2025
• Q2: June 16, 2025
• Q3: September 15, 2025
• Q4: January 15, 2026

Missing the Q3 estimated tax deadline could result in an underpayment penalty, even if you catch up by tax filing season. See the IRS payment calendar: IRS Payment Options.

How to Calculate Your Q3 Estimated Taxes

You can calculate your estimated payment using IRS Form 1040-ES. Here’s the process:

1. Estimate annual income. Include all untaxed income sources like self-employment, dividends, or rental earnings.
2. Subtract deductions and credits. Adjust for business expenses, standard deduction, or itemized deductions.
3. Apply tax rates. Use current brackets for income tax plus 15.3% self-employment tax if applicable.
4. Divide by four. Your total annual liability divided by four gives a baseline for each quarter. Adjust for income fluctuations.

Tip: If income varies, you can use the annualized income method to calculate payments more accurately and avoid penalties.

How to Pay Q3 Estimated Taxes

The IRS offers several secure ways to pay IRS online:

• Direct Pay – Best for individuals paying from a bank account, no fees.
• EFTPS – Ideal for businesses, freelancers, or anyone scheduling multiple payments.
• Debit/Credit Card – Fast, but includes processing fees.

Always pay electronically when possible. It’s faster, safer, and provides instant confirmation.

Safe Harbor Rules

Worried about paying too little? The IRS penalty rules include a safe harbor provision. You won’t owe an underpayment penalty if you’ve paid at least:

• 90% of your current year’s total tax liability, OR
• 100% of your prior year’s tax liability (110% if your AGI was over $150,000).

This can protect you if income jumps late in the year.

Key Takeaways

• The Q3 estimated tax deadline is September 15, 2025.
• Use IRS Form 1040-ES or software to calculate accurately.
• Pay online via Direct Pay or EFTPS for fastest processing.
• Leverage safe harbor rules to avoid penalties.

Related Reading

• Common Estimated Tax Mistakes (2025)
• IRS Online Payment Options (2025)

Want extra tools to manage your quarterly taxes and stay penalty-free? Explore the Side Hustle Guide, OIC Checklist, and Home Office Toolkit.

Disclaimer

Disclaimer: The information provided in this blog post is for informational purposes only and should not be construed as legal, tax, or accounting advice. Tax situations are often complex and highly specific to the individual or business. You should contact a qualified tax expert directly to discuss your particular circumstances. Nothing herein is intended to, nor does it, create an attorney-client or advisor-client relationship. For individual guidance, please contact us directly.