Quarterly Tax Calculator (Estimated Payments & Safe Harbor)
Work out your 2026 federal safe-harbor target and the quarterly payment that gets you there. The calculator compares both safe-harbor routes, 90% of this year versus 100-110% of last year, picks the cheaper one, and subtracts what you've already had withheld.
After deductions: income minus your standard or itemized deduction
Sets the federal brackets used for the estimate
Net profit from freelancing or a business; drives the SE tax layer
The total tax line on last year's return, before payments
Was last year's AGI above $150,000?
W-2 withholding and estimates already paid count toward the target
Per-quarter payment
$4,000
four payments toward the $16,000 target
Safe-harbor target (year)
$16,000
the prior-year route is the cheaper anchor here
This year's estimated tax
$19,216
$7,912 income tax + $11,304 SE tax
Route 1: 90% of this year
$17,294
always available, but depends on forecasting this year well
Route 2: 100% of last year
$16,000
a fixed number the day you file the prior return
The four payment periods
| Payment | Due around | Amount |
|---|---|---|
| Payment 1 | mid-April | $4,000 |
| Payment 2 | mid-June | $4,000 |
| Payment 3 | mid-September | $4,000 |
| Payment 4 | mid-January (next year) | $4,000 |
Exact due dates move a day or two for weekends and holidays, so they are labeled by month here. Note the uneven rhythm: the second period is only two months long, and the last payment lands in January of the following year.
Educational estimate for the 2026 tax year, not tax advice. Federal figures follow IRS inflation adjustments; state estimates use statewide rates and standard deductions only and exclude local income taxes (city, county, school district), State Disability Insurance, and credits. Where a state publishes separate married tables, married thresholds may be approximated. Verify your exact withholding with a tax professional or your payroll provider.
Safe harbor, in plain English
The US tax system is pay-as-you-go: the IRS wants its money as you earn, not in one April lump. Employees comply automatically through withholding; everyone else does it with estimated payments. The safe harbor is the deal that makes this manageable. Pay enough during the year to reach either 90% of this year's tax or 100% of last year's (110% if last year's AGI was above $150,000), whichever is smaller, and you owe no underpayment penalty, even if the final bill turns out much bigger. You would still pay the remaining balance at filing, just without the penalty on top.
The math this tool runs
First it estimates this year's federal tax: income tax on your taxable income (that means after deductions, so start from income minus your standard or itemized deduction) plus self-employment tax on your net profit, computed the same way the self-employment tax calculator does. It then takes the smaller of the two safe-harbor routes, subtracts tax already withheld, and splits the rest into four payments. Withholding is treated as spread evenly across the year no matter when it happens, which is a quirk worth knowing: a year-end withholding boost can retroactively fix earlier quarters.
A freelancer's four payments, worked through
Take a single filer expecting $60,000 of taxable income, all of it from $80,000 of self-employment profit. Income tax comes to about $7,912 and SE tax adds $11,304, for a $19,216 estimate. Route one is 90% of that, $17,294. If last year's total tax was $16,000, route two is $16,000, the cheaper anchor. With nothing withheld, that means four payments of about $4,000. Setting aside a slice of every invoice as it arrives, the way our irregular-income guide suggests, makes those dates a non-event.
Penalties are interest, not punishment
Missing the safe harbor is not a crime and does not trigger an audit. The underpayment penalty is calculated like interest on the amount you were short, for the days it was short. That reframing matters: an underpayment is a loan from the IRS at an unattractive rate, so the fix is simply to catch up as early as you can. Many states run their own parallel estimated-tax systems, so if you live in one with an income tax, budget for a state payment alongside each federal one.
Frequently asked questions
Who has to make quarterly estimated payments?
Anyone whose withholding will not cover most of their tax bill: freelancers and contractors, small-business owners, landlords, and investors with meaningful gains. W-2 employees usually do not, because payroll withholding handles it, but a large side income or investment year can put an employee into estimated-payment territory too.
What does the safe harbor actually protect me from?
The underpayment penalty. If your payments during the year reach the smaller of 90% of this year's tax or 100% of last year's (110% if last year's AGI was above $150,000), no penalty applies even if you still owe a large balance in April. The remaining balance is simply due at filing, penalty-free.
Why do higher incomes use 110% of last year's tax?
The prior-year route is a certainty play: it lets you lock a target the day you file last year's return, no forecasting needed. For filers whose AGI was above $150,000, the law makes that convenience slightly more expensive by requiring 110% rather than 100%, so high earners with rising income cannot lean too hard on a much smaller old bill.
What if I miss a payment or my income is uneven?
The penalty works like interest on the shortfall for the time it was short: not a fine, not a legal problem, just a carrying cost. Paying as soon as you can stops it growing. If your income arrives unevenly, the IRS also allows an annualized method that matches payments to when the money actually showed up, which a tax professional can set up.
How accurate is this calculator?
Educational estimate for the 2026 tax year, not tax advice. Federal figures follow IRS inflation adjustments; state estimates use statewide rates and standard deductions only and exclude local income taxes (city, county, school district), State Disability Insurance, and credits. Where a state publishes separate married tables, married thresholds may be approximated. Verify your exact withholding with a tax professional or your payroll provider.
Does this calculator save my numbers?
No. Everything runs in your browser and nothing you type is stored or sent anywhere.
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