Next federal deadline Sep 15 in 9 days
Your quarterly payment computed, not guessed Compare both IRS payment methods
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Q3 2026 estimate
Single filer · self-employment income
Pay this quarter
$8,227.00
Due Sep 15
Safe harbor
100% of 2025 tax
$9,878.00
Annualized income Selected
Schedule AI, this year's actual income
$8,227.00
Sample calculation
Run yours free →Built on the IRS's own rules
One calculation covers the quarter. It gives you the payment, the proof, the deadlines, and the filing paper trail.
Know if you're on track today
Every deadline has a required amount. See where you stand while the quarter is still open, not on next year's return.
Required by Sep 15
$15,000.00
Paid in so far
$7,500.00
Behind by $7,500.00
No penalty if paid by Sep 15
Never miss a deadline
A reminder lands in your inbox before every federal due date, with your number in it.
Q3 estimate due Sep 15
Your payment is $8,227. Pay at IRS Direct Pay before the deadline.
7 days out
Q2 estimate confirmed
You marked $4,547 paid on Jun 12. Your year is up to date.
Jun 12
Both official methods, side by side
Safe harbor protects you with last year's tax. Annualized income follows the year you're actually having. The calculator runs both from Publication 505 and recommends the lower penalty-free payment.
Setting aside a flat 30% is a guess that costs money in both directions. The computed number is checkable, and in this sample it is $1,651 lower this quarter.
Safe harbor
Based on last year's total tax
$9,878.00
Annualized income Selected
Based on this year's actual income
$8,227.00
Sample calculation
Form 2210
Underpayment of Estimated Tax
Schedule AI
Annualized Income Installment Method
1040-ES voucher
Filled for Q3, ready to mail
Defensible at filing
Uneven payments are justified to the IRS with Form 2210 and Schedule AI. The same calculation that gave you the quarterly number produces the paper trail that defends it in April.
See every line the IRS sees. Nothing here is a black box.
You get the whole worksheet. Income, self-employment tax, the required annual payment, and each installment are shown line by line, so you or your accountant can check any figure against the source.
Rough numbers are fine to start. Sharpen any line later and the whole worksheet recomputes.
Start your worksheet2026 estimate worksheet
Single · self-employed · sample
2
Official IRS methods computed on every calculation
4
Federal deadlines tracked, with a reminder before each
$0
To get your quarterly number. No card required
0
SSNs stored, ever. You type dollar amounts, nothing links to your accounts
Each year's brackets and thresholds are audited against IRS source documents and pinned by automated tests. Tax logic reviewed by Steven Wu, CPA, formerly of PwC. Meet the team
Not filing as an individual? You get the same calculations, set up for how you work.
Business owners
Business income is seasonal, and equal installments ignore that. The annualized method sizes each payment to the quarter that earned it, whether you run a sole prop, an LLC, or take an S-corp salary plus K-1.
Simple Estimates for businessesAccountants
Every client's quarterly numbers in one dashboard, computed both official ways, with filled 1040-ES vouchers and PDF reports ready to send. Direct worksheet entry, no interview required.
Simple Estimates for accountantsUnderstand the rules you're paying under. Every guide is written in plain language and sourced from the IRS.
The safe harbor rule, explained.
How last year's tax can protect this year's payments, and when the 110% threshold applies.
Read the guideDo you even need to pay quarterly?
Generally yes if you'll owe $1,000 or more beyond withholding. Who that covers, and how to check either way.
Read the guideUneven income and Schedule AI.
Why a windfall or a slow start changes each quarter's required payment, and how to prove it.
Read the guideGet your quarterly payment. The next deadline is Sep 15. The check is free.
Free to check. No card, no SSN, no password. We email you a 6-digit code to sign in.