TL;DR: In the US, self-employed people pay quarterly estimated tax on April 15, June 15, September 15, and January 15. In 2026, the due dates are April 15, June 15, September 15, 2026, and January 15, 2027. You must pay at least 90% of your current-year tax or 100% of your prior-year tax (110% if your 2025 AGI was over $150,000) to avoid the IRS underpayment interest, which ran at 6–7% in 2026. Self-employment tax is 15.3% of 92.35% of net earnings. In Pakistan, non-salaried individuals pay advance tax in four installments: September 25, December 25, March 25, and June 15.
What is quarterly estimated tax?
Quarterly estimated tax is a pay-as-you-go tax system: instead of withholding from a paycheck, self-employed people estimate their annual tax and pay it in four installments during the year. In the US this covers income tax plus self-employment tax (15.3% of 92.35% of net earnings in 2026: 12.4% Social Security up to the $184,500 wage base and 2.9% Medicare, plus 0.9% Additional Medicare above $200,000 single or $250,000 married filing jointly).
US quarterly estimated tax deadlines for 2026
| Payment Period | Due Date |
|---|---|
| 1st quarter (Jan 1 – Mar 31) | April 15, 2026 |
| 2nd quarter (Apr 1 – May 31) | June 15, 2026 |
| 3rd quarter (Jun 1 – Aug 31) | September 15, 2026 |
| 4th quarter (Sep 1 – Dec 31) | January 15, 2027 |
If a due date falls on a weekend or federal holiday, the payment is due the next business day. Late or missed installments are charged underpayment interest: the IRS underpayment rate for individuals in 2026 was 7% for Q1 and Q3 and 6% for Q2, compounded daily, applied to the amount and the period of the shortfall (Form 2210).
How do I calculate my quarterly estimated tax payments?
- Estimate total taxable income for the year (project business profit minus deductions).
- Compute income tax on that amount using the 2026 brackets and your filing status.
- Compute self-employment tax: 15.3% of 92.35% of net self-employment earnings (Social Security capped at $184,500 in 2026).
- Subtract any credits, and remember the deductible half of self-employment tax (7.65% of 92.35% of earnings) reduces your income tax.
- Divide the total by 4 (or use the annualized income installment method on Form 2210 when income arrives unevenly).
Safe harbor: how to avoid the penalty
You avoid the underpayment penalty if you pay at least 90% of your current-year tax or 100% of your prior-year tax (110% if your 2025 adjusted gross income exceeded $150,000, or $75,000 if married filing separately). Most freelancers with stable income pay 100% of last year's tax and adjust at filing.
Quarterly estimated tax with fluctuating income
For gig workers and freelancers, income arrives unevenly. Use the annualized income installment method (Form 2210-AI): it allows smaller payments early in the year when income is low, with larger later payments as income catches up. This avoids overpaying early and underpaying late. A practical alternative: set aside 25–30% of every invoice in a separate account and pay from it quarterly.
Comparison: manual calculation vs tools
Free calculators estimate your quarterly payment in seconds, which is the fastest way to plan and avoid penalties; tax software and accountants add accuracy for complex situations (multiple businesses, estimated credits, or large income swings). For most self-employed filers, a calculator plus the safe-harbor rule is enough to stay penalty-free.
| Option | Best for | Limits |
|---|---|---|
| Free online calculator | Quick planning, deadline reminders, steady income | No filing, no deductions research |
| Tax software (TurboTax, etc.) | Annual return filing, W-4/estimated integration | Paid tiers, learning curve |
| CPA/EA | Complex income, AMT, quarterly planning | Cost |
How do I pay quarterly estimated tax in the US?
- IRS Direct Pay (free, direct from bank).
- IRS2Go mobile app.
- Electronic Federal Tax Payment System (EFTPS) — free, recommended for businesses.
- Check with Form 1040-ES payment voucher.
Use our free tools to estimate the tax first — US self-employment tax calculator and US federal income tax calculator — then pay the IRS directly.
Quarterly advance tax in Pakistan (self-employed)
In Pakistan, non-salaried individuals and AOPs pay advance income tax in four installments — September 25, December 25, March 25, and June 15 of the tax year — based on 100% of the tax payable on their estimated annual income. Salaried employees normally skip this because employers withhold at source.
The installments apply to taxpayers whose tax payable after withholding exceeds the relevant threshold. Each installment is typically 25% of the estimated annual tax; the amount is credited against the final liability when the return is filed. Missed installments attract default surcharge, so freelancers with irregular income should estimate conservatively and review after each quarter.
Estimate your liability with the Pakistan income tax calculator using the non-salary income type, and see our freelancer FBR tax planning guide for registration and filing steps.
What happens if I miss a quarterly deadline?
In the US, you owe underpayment interest (6–7% annualized in 2026, compounded daily) plus possible penalties on the shortfall — no fixed flat fine. In Pakistan, late advance tax installments attract default surcharge on the unpaid amount. In both countries, paying as soon as you notice the miss limits the damage.
Important disclaimer
This article is for educational planning only. It does not provide professional tax, legal, accounting, payroll, customs, or financial advice. Tax rules can change and final results may depend on your personal facts. Always verify important tax decisions with official sources or a qualified professional.