How to calculate quarterly taxes in 2025 — a plain-English checklist for solo pros
Updated January 2025 · ~7 min read
If you're a freelancer, single-member LLC, or S-corp owner, the IRS wants you to pay tax as you earn — not once a year in April. That's what quarterly estimated taxes are. This is the plain-English 2025 version: who owes them, how to calculate the number, when to pay, and how to avoid a penalty.
Prefer to just get the number? Our free 2025 quarterly tax calculator walks you through the same steps below and gives you a printable summary with due dates.
Do you actually owe quarterly taxes?
You owe quarterly estimated tax in 2025 if you expect to owe at least $1,000 in federal tax after withholding. That usually means anyone earning 1099 income, running a single-member LLC, or taking S-corp distributions without enough W-2 withholding to cover the year.
The 2025 due dates
- • Q1 — April 15, 2025 (covers Jan–Mar)
- • Q2 — June 16, 2025 (covers Apr–May)
- • Q3 — September 15, 2025 (covers Jun–Aug)
- • Q4 — January 15, 2026 (covers Sep–Dec)
The 5-step calculation
1. Estimate net self-employment income
Take your projected gross revenue for the year and subtract deductible business expenses — software, home office (simplified: $5/sq ft up to 300 sq ft), business miles ($0.70/mile in 2025), marketing, meals (50%), professional services, and so on. What's left is your net self-employment income.
2. Calculate self-employment (SE) tax
SE tax is 15.3% (12.4% Social Security + 2.9% Medicare) on 92.35% of net SE income. Social Security applies only up to $176,100 in 2025. Half of the SE tax is deductible above the line — it reduces your AGI, not your SE tax itself.
3. Figure out taxable income
Start with net SE income, add W-2 wages and other income, subtract the half-of-SE-tax deduction, SEP-IRA/HSA/student loan interest, and self-employed health insurance. That's your AGI. Subtract the standard deduction ($15,000 single, $30,000 MFJ in 2025) or itemized, then subtract up to 20% for the QBI deduction if you qualify.
4. Apply the 2025 federal brackets
Federal income tax uses graduated brackets — 10%, 12%, 22%, 24%, 32%, 35%, 37%. Add state tax (varies by state) and any additional 0.9% Medicare surtax if wages + SE earnings exceed the threshold for your filing status.
5. Divide by 4 and pay
Total estimated tax minus expected withholding equals your balance owed. Divide by 4 to get each quarterly payment. Pay directly at IRS.gov/payments or through EFTPS.
The safe harbor rule — how to avoid the penalty
The IRS won't hit you with an underpayment penalty as long as you've paid the lesser of:
- • 90% of the current year's tax, or
- • 100% of last year's total tax (110% if last year's AGI was over $150,000).
Most solo pros use option 2 — it's a fixed target you already know.
S-corp owners: it's different
If your business is an S-corp, you pay yourself a reasonable W-2 salary and take the rest as distributions. Payroll taxes come out of the salary; distributions are taxed as income but not subject to SE tax. Your quarterly estimate covers the tax on distributions plus any shortfall on salary withholding.
The Number handles all five steps above — Schedule C or S-corp, federal, state, SE tax, and safe-harbor. It's free and there's no login.
Educational content, not tax advice. For binding decisions, work with a licensed CPA or Enrolled Agent.