Estimated Tax Payment Calculator

Size each Form 1040-ES payment using the IRS safe-harbor rule — the lower of 90% of this year's tax or 100% (110% if AGI > $150K) of last year's tax.

Hitting safe harbor zeroes out the 8% underpayment penalty, even if you owe a balance at filing.

Your tax year inputs

The IRS uses a "safe harbor" rule. Pay the lower of 90% of this year's tax OR 100% (110% if AGI > $150K) of last year's tax — and you owe zero underpayment penalty.

Each quarterly payment
$1,875
Safe-harbor annual
$7,500
Still owed this year
$7,500

Safe-harbor calculation

Projected total tax (this year)$11,163
90% of this year$10,046
100% of last year$7,500
Safe-harbor target (lower of two)$7,500
Less: W-2 withholding− $0
Less: payments already made− $0
Per quarter (÷ 4)$1,875
Effective rate on gross18.6%

2026 IRS due dates

Q1 2026
Jan 1 – Mar 31
$1,875
due April 15, 2026
Q2 2026
Apr 1 – May 31
$1,875
due June 15, 2026
Q3 2026
Jun 1 – Aug 31
$1,875
due September 15, 2026
Q4 2026
Sep 1 – Dec 31
$1,875
due January 15, 2027

Pay via IRS Direct Pay or EFTPS. Missing a deadline triggers an 8% APR underpayment penalty (2026 rate), even if you square up at filing.

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