Who has to pay quarterly estimated tax?

Anyone who expects to owe $1,000+ in tax after withholding and refundable credits. Typically: self-employed individuals, partners, S-corp shareholders, landlords, and high-investment-income earners. Corporations have separate rules (Form 1120-W).

What is the safe harbor?

Pay at least 90% of current-year tax OR 100% of prior-year tax (110% if prior-year AGI exceeded $150,000) — whichever is less. Meeting either avoids the underpayment penalty even if you owe a large balance at filing.

When are quarterly estimates due?

April 15 (Q1, covers Jan–Mar), June 15 (Q2, covers Apr–May), September 15 (Q3, covers Jun–Aug), and January 15 of the following year (Q4, covers Sep–Dec). These are not calendar quarters.

Does this calculator handle state estimates?

No — federal only. State estimates vary widely. California, for example, uses a 30/40/0/30 split on different dates. Check your state's department of revenue or use a CPA for state-specific cadence.

Free Calculator

Quarterly Estimated Tax Calculator

Picks the cheaper of two IRS safe harbors and divides into four quarterly payments. Federal only — state estimates run on separate schedules.

Your situation

Pick whichever safe-harbor method is cheaper. The prior-year method is the most predictable — it locks in your minimum required.

Prior-year federal tax (line 24 of Form 1040)$40,000

Prior-year AGI (line 11 of Form 1040)$180,000

Current-year estimated total tax$50,000

W-2 withholding already covered this year$0

Each quarterly estimate

$11,000

due Apr 15, Jun 15, Sep 15, and Jan 15 (next year)

Prior-year safe harbor (110%)$44,000

90% of current-year tax$45,000

Method chosenPrior-year safe harbor (110% of last year's tax)

Target total payments this year$44,000

Less W-2 withholding-$0

Required estimates total$44,000

Read this carefully

Federal only. State estimates (especially California's 30/40/0/30 schedule) are separate. Q2 covers only Apr–May; Q3 covers Jun–Aug. Pay via IRS Direct Pay or EFTPS. Talk to a partner.

Estimates for educational purposes only — not tax, legal, or accounting advice. Your specific facts will change the result; confirm with a CPA before acting.

Want help with multi-state estimates?

California, New York, and other states each have their own estimated-tax schedules and safe-harbor rules. We handle federal and multi-state estimates as part of every tax engagement.

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Glossary

Quarterly Estimated Tax Calculator

Your situation

Want help with multi-state estimates?

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Quarterly Estimated Tax for Self-Employed and Business Owners

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