Quarterly Tax Estimator - Calculate Self-Employment Taxes
Seller Bookkeeping

Quarterly Tax Estimator

Calculate quarterly self-employment tax payments for online sellers

Understanding Quarterly Taxes

Quarterly estimated taxes are payments you must make 4 times per year if you're self-employed. The IRS requires this because taxes aren't automatically withheld from your income like they would be at a W-2 job.

2025 Payment Dates: April 15 | June 16 | September 15 | January 15, 2026

Most online sellers must pay both income tax AND self-employment tax (Social Security + Medicare). Self-employment tax alone is 15.3% of your net profits—easily $1,000+ quarterly on a $50K business.

Quarterly Tax Estimator 2025

Estimates income tax + self-employment tax

Total revenue before expenses (Amazon sales, Shopify, etc.)
COGS, fees, advertising, shipping, etc.
Affects standard deduction & tax brackets
Optional - increases your tax bracket
Gross Income (Annual): $0.00
- Business Expenses: $0.00
= Net Profit: $0.00
Self-Employment Tax (15.3%): $0.00
Estimated Income Tax: $0.00
TOTAL ANNUAL TAX: $0.00
QUARTERLY PAYMENT (÷ 4): $0.00

2025 Payment Dates:
Q1: April 15 | Q2: June 16 | Q3: September 15 | Q4: January 15, 2026

Important Disclaimer

This calculator provides estimates only. Actual tax liability depends on many factors not included here (state taxes, deductions, tax credits, Alternative Minimum Tax, etc.). Consult with a CPA or tax professional before making quarterly payments. Failure to pay estimated taxes can result in penalties and interest.

Tax Facts for Sellers

15.3%

Self-employment tax rate (12.4% SS + 2.9% Medicare)

$1,000+

Minimum annual tax to require quarterly payments

4

Quarterly payments required per year

10%

Accuracy penalty for underpayment of estimated tax

$176,100

2025 Social Security wage base limit

92.35%

Percentage of net profit subject to SE tax

Quarterly Tax FAQ

Do I have to pay quarterly taxes?

Yes, if you expect to owe $1,000 or more in taxes during the year. Most online sellers do. Missing quarterly payments can result in IRS penalties and interest. It's safer to pay quarterly if you're self-employed.

What if I underpay my quarterly taxes?

The IRS charges penalties (typically 3-7% depending on how much you're short) and interest on the unpaid amount. If you underpay significantly, the IRS may audit you or place a lien on your business. Always try to pay the full amount or at least 90% of your estimated tax.

Can I use my prior year's taxes to estimate?

Yes. If your 2024 tax liability was $0, you can wait to file your 2025 return. Otherwise, use the safe harbor: pay 100% of your 2024 tax liability (or 110% if your 2024 AGI was over $150,000) as estimated tax to avoid penalties.

How do I actually make the payment?

Use IRS Direct Pay (free), Electronic Federal Tax Payment System (EFTPS), or pay by credit/debit card (fees apply). File Form 1040-ES with your payment, or pay online at IRS.gov. Keep proof of payment for your records.

What counts as "business expenses"?

COGS, referral fees, fulfillment costs, storage fees, advertising, office supplies, internet, phone, professional services (CPA), business software, shipping materials. NOT included: personal expenses, car depreciation (claimed separately), home office deduction (also separate), or meals/entertainment (typically 50% deductible).

Should I hire a CPA for quarterly taxes?

If your annual income exceeds $50,000, yes. A CPA ($100-200/quarter) ensures accurate estimates, identifies deductions you miss, and helps you avoid penalties. For most sellers, their fee saves more in taxes than it costs. At minimum, get a CPA review of your estimates once.

What if my income fluctuates throughout the year?

You can adjust your quarterly payments using Form 1040-ES annualization method. If Q1 you made $15K but Q2 you expect $5K due to seasonality, you can reduce your Q2 payment accordingly. This requires good income tracking and planning ahead.

Is self-employment tax deductible?

Yes! You can deduct half of your self-employment tax when calculating your adjusted gross income. This reduces your taxable income by roughly 7.65% of your net profit. Your CPA or tax software should handle this automatically.