Freelancers owe estimated taxes four times a year: April 15, June 15, September 15, and January 15, 2027. Pay 90% of this year's tax or 100% of last year's (110% if prior AGI topped $150,000), whichever is smaller. A single 1099 worker netting $90,000 owes about $22,288 for 2026, roughly $5,015 a quarter.
Income tax is pay-as-you-go by design. Employees never notice because withholding sends money to the IRS with every paycheck. When nobody withholds for you, the system still expects its rhythm, so it bills you four times a year instead. Cross the $1,000 threshold of unpaid tax at filing time and the underpayment machinery starts turning.
The payments aren't advance tickets on next April's refund, either. Each installment is due as the income it covers is earned, which is why the calendar looks lopsided: Q1 covers three months, Q2 only two (April and May), Q3 three, and Q4 four. June's check always feels like it comes too fast.
Two stacks, added together. The first is self-employment tax: 15.3% on 92.35% of your net profit, with the 12.4% Social Security piece capped at $184,500 of 2026 earnings and 2.9% Medicare running forever (plus 0.9% above $200,000 single or $250,000 joint). The second is regular income tax, computed on your profit plus any wages, minus half your SE tax, minus the standard deduction ($16,100 single or $32,200 joint for 2026), through the ordinary brackets.
Here's the full stack for a single freelancer expecting $90,000 of net profit:
Ninety percent of that is $20,059, so the even-payment plan is $5,015 a quarter. The self-employment tax calculator breaks out the SE side if that's the number you're sanity-checking.
The safe harbor is the escape hatch from guessing well. Meet either test and there's no underpayment penalty no matter what you actually owe in April: pay 90% of the current year's tax, or pay 100% of last year's total tax (110% if last year's AGI was above $150,000).
Suppose our freelancer paid $18,000 of total tax last year with AGI under $150,000. The prior-year harbor allows four payments of $4,500 instead of $5,015. April brings a bill for the remaining $4,288, but zero penalties. That's the trade: smaller checks through the year, lump sum later. It's the right call when cash flow is tight; the wrong one if you'd rather not write a four-figure check in spring.
Enter expected profit, withholding, and last year's tax. The calculator picks the smaller safe harbor and shows both.
Quarterly Tax Calculator →Equal quarters assume equal income, and gig work rarely cooperates. If you earned nothing in Q1 and a fortune in Q4, paying even quarters overpays early. Form 2210's annualized income method (Schedule AI) lets you size each payment to what you'd owed so far. The price is paperwork: you annualize income period by period and attach the schedule to your return. Most people with steady-ish income skip it, but seasonal workers can save real penalty dollars.
The hybrid crowd (W-2 day job plus 1099 side work) has a cleaner trick. Increase withholding on the W-4 instead of making estimated payments. Withholding is treated as paid evenly through the year regardless of when it was actually withheld, so a December bump can retroactively cure an underpaid spring. Estimated payments get no such amnesty.
No sirens go off. The IRS quietly computes interest on the shortfall for each quarter at a floating federal rate, recently 7% to 8% annually, compounding daily, and presents the total as an "estimated tax penalty" on your return. Skip a $5,000 Q2 payment for six months and the damage is roughly $175 to $200; annoying, not ruinous. The habit is what costs: skipping all four quarters on a $22,000 bill runs into four figures by April.
Paying is frictionless at IRS.gov/payments through Direct Pay, free, no account needed for bank debit. EFTPS is the business-grade option. Whatever the channel, keep confirmation numbers; payments applied to the wrong tax year are a classic tax-season headache.
| Quarter | Covers | Due |
|---|---|---|
| Q1 | Jan 1 – Mar 31 | April 15, 2026 |
| Q2 | Apr 1 – May 31 | June 15, 2026 |
| Q3 | Jun 1 – Aug 31 | September 15, 2026 |
| Q4 | Sep 1 – Dec 31 | January 15, 2027 |
Set four recurring calendar reminders and you'll never think about Form 2210 again. For the bracket side of the estimate, the income tax calculator handles the withholding-plus-wage version of the math.
⚖️ Not tax advice. Federal formulas as published for 2026; state estimated taxes run on their own calendars. A CPA who can see your actual books beats any calculator.
Estimate your full-year federal tax (self-employment tax plus income tax after the standard deduction), then pay 90% of it across four installments, or 100% of last year's total tax (110% if prior-year AGI exceeded $150,000), whichever is smaller. A single freelancer with $90,000 of net profit owes about $22,288 for 2026: $5,015 a quarter at the 90% target, or $4,500 if the prior-year safe harbor applies with an $18,000 prior tax.
April 15, June 15, and September 15, 2026, plus January 15, 2027. The periods covered are uneven on purpose: Q2 covers only April and May, while Q4 covers four months. Dates that land on weekends or holidays slide to the next business day.
If your prior-year adjusted gross income was more than $150,000 (or $75,000 married filing separately), the prior-year safe harbor rises from 100% of last year's tax to 110%. The point is to stop high earners from lowballing payments on a small prior-year bill while current income climbs.
There's no fixed fine; the IRS charges interest on the shortfall, computed per quarter at a floating federal rate that has recently run 7% to 8% annually and compounds daily. Missing a quarter by a month costs far less than missing it by a year, but it does show up as a Form 2210 calculation on your return.