Key Takeaways

  • Required if expecting to owe $1,000+ after withholding/credits.
  • Due dates: April 15, June 15, September 15, January 15.
  • Safe harbor: 90% current year OR 100% prior year tax.
  • High-income (AGI >$150k): Must pay 110% of prior year.
  • Underpayment penalty calculated on Form 2210.
  • Annualized income method available for seasonal businesses.
Last updated: January 2026

Estimated Tax Payments

Why This Matters for the Exam

Estimated tax is tested every exam. Know the due dates, safe harbor rules, and high-income exception.

Expect at least 2-3 questions on estimated taxes.

Who Must Pay?

You must make estimated tax payments if:

RequirementThreshold
Expected tax owed$1,000 or more
Withholding/creditsLess than 90% current year OR 100% prior year

Quarterly Due Dates

PeriodIncome PeriodDue Date
1stJan 1 - Mar 31April 15
2ndApr 1 - May 31June 15
3rdJun 1 - Aug 31September 15
4thSep 1 - Dec 31January 15 (next year)

Safe Harbor Rules

To avoid penalty, pay at least:

TestRequirement
Current year90% of current year tax
Prior year100% of prior year tax
Meet eitherSafe harbor satisfied

High-Income Exception

Prior Year AGISafe Harbor
≤$150,000100% of prior year
>$150,000110% of prior year
MFS >$75,000110% of prior year

Safe Harbor Example

ItemAmount
2023 tax liability$10,000
2023 AGI$180,000
2024 estimated tax requirement$10,000 × 110% = $11,000

Underpayment Penalty

FeatureRule
CalculationForm 2210
RateIRS interest rate (quarterly)
Per quarterPenalty calculated separately
No forgivenessLate Q1 not fixed by early Q4

Annualized Income Method

For seasonal businesses or businesses that start mid-year:

FeatureBenefit
FormForm 2210, Schedule AI
EffectBase payments on actual income each period
ExampleBusiness starts in October—no Q1-Q3 payments required

Special Rules: Farmers and Fishermen

RuleDescription
Single paymentOne payment by January 15
AlternativeFile return and pay by March 1
Threshold≥2/3 of gross income from farming/fishing

Real-World Scenario

Scenario: Taxpayer expects to owe $8,000 for Tax Year 2024. Prior year tax was $6,000. Prior year AGI was $140,000.

  • Current year 90%: $8,000 × 90% = $7,200.
  • Prior year 100%: $6,000.
  • Safe harbor: Pay at least $6,000 (lesser of two tests).
  • Quarterly payments: $6,000 ÷ 4 = $1,500 each quarter.

High-Income Scenario

Scenario: Prior year tax $50,000. Prior year AGI $200,000.

  • Safe harbor: 110% of prior year = $55,000.
  • Quarterly payments: $55,000 ÷ 4 = $13,750 each quarter.

On the Exam

Expect 2-3 questions on estimated taxes, typically:

  1. Due Date Questions: "When is Q3 estimated tax due?"
  2. Safe Harbor Questions: "What is the safe harbor for AGI >$150k?"
  3. Threshold Questions: "What triggers estimated tax requirement?"

The key is to remember: $1,000 threshold. Due Apr 15, Jun 15, Sep 15, Jan 15. Safe harbor = 90% current OR 100% prior. High-income = 110% prior.

Test Your Knowledge

Taxpayer expects $5,000 tax. Prior year was $4,000, AGI $100,000. Minimum safe harbor payment?

A
B
C
D
Test Your Knowledge

Prior year: AGI $200,000, tax $40,000. Minimum estimated tax for current year under prior-year safe harbor?

A
B
C
D
Test Your Knowledge

When is the 3rd quarterly estimated tax payment due?

A
B
C
D