Quarterly estimated taxes are the IRS's way of saying: if your employer isn't withholding for you, you have to do it yourself, four times a year. Most freelancers learn this the painful way — usually after their first year filing as self-employed and getting hit with a $400 underpayment penalty.
This guide explains who owes them, the simplest way to calculate, and the 2026 due dates.
Who owes estimates in 2026
- Anyone who expects to owe more than $1,000 at tax time after withholding and credits.
- Self-employed workers, freelancers, gig workers, landlords, and investors with significant unwithheld income.
- W-2 workers with large side income if their employer withholding doesn't cover the total.
Roughly 10 million Americans pay quarterly estimates, per IRS data. The number is growing about 6% per year as gig work expands.
How safe harbor works (and why it's the only rule that matters)
You avoid the underpayment penalty if any of these are true:
- You paid at least 90% of this year's tax through withholding plus estimates
- You paid at least 100% of last year's tax (110% if last year's AGI was over $150,000)
- You owe less than $1,000 after withholding
The second one — 100% of last year's tax — is the easy button. Pull last year's Form 1040, find the total tax line, divide by four, send that amount each quarter. Done.
2026 due dates
- Q1: April 15, 2026 (covers Jan 1 – March 31 income)
- Q2: June 15, 2026 (covers April 1 – May 31 — note the two-month gap)
- Q3: September 15, 2026 (covers June 1 – August 31)
- Q4: January 15, 2027 (covers September 1 – December 31)
The "quarters" aren't actually quarters. Q2 covers two months. The dates are fixed by statute and won't change.
1. The safe-harbor method — best for stable income
Take last year's total tax (Form 1040 line 24). Divide by four. Pay that each quarter. You'll never owe a penalty no matter what happens to this year's income.
The trade-off: if you earn dramatically less this year, you'll have a big refund. That's interest-free money loaned to the IRS.
2. The annualized income method — best for lumpy income
Form 2210 Schedule AI lets you pay based on income earned each quarter rather than equal installments. Useful if you have a slow Q1 and a huge Q4 (consultants, real estate agents, anyone with seasonal sales).
The catch: Schedule AI is genuinely tedious. Most people don't use it.
3. The W-2 withholding hack — best for couples
If your spouse has a W-2, increase their withholding to cover your self-employment tax. W-2 withholding is treated as if paid evenly through the year, even if you bump it in December. This lets you skip estimates entirely.
Comparison: payment methods in April 2026
| Method |
Cost |
Speed |
Best for |
| IRS Direct Pay |
Free |
Same day |
Most filers |
| EFTPS |
Free |
Schedule in advance |
Recurring auto-pay |
| Debit card |
$2.10 flat fee |
Same day |
One-off |
| Credit card |
1.82–1.98% fee |
Same day |
Earning rewards on large amounts |
| Mail with Form 1040-ES |
Postage |
7–10 days |
Filers without bank account |
Common mistakes to avoid
Forgetting state estimates. Most states have their own quarterly system with different due dates and forms. California's are particularly aggressive — front-loaded into Q1 and Q2.
Treating quarters as equal. Q2 is two months and Q4 is four months. The amounts are equal but the time covered isn't.
Skipping a quarter because income was low. The penalty is calculated quarter by quarter. Skipping Q1 doesn't get fixed by paying double in Q2.
FAQ
What's the underpayment penalty?
About 8% annualized in 2026, calculated on the shortfall for each quarter. Small for small misses, painful for large ones.
Can I just pay it all in Q4?
Only if you used the W-2 withholding hack. Otherwise the IRS will assess penalties for Q1, Q2, and Q3.
Do I include self-employment tax in estimates?
Yes. Self-employment tax (15.3%) and income tax both go in the same estimate.
Where to go next
For related guides see Self-employed tax deductions in 2026, Side hustle taxes 2026, and How to set up automated invoicing for freelancers in 2026.