Figures: tax year 2026
To define safe harbor compliance for individual estimated tax payments, the candidate identifies the required payment amount and installment timing that avoid underpayment penalties. Meeting these requirements can leave a balance due with the return.
Candidates recall that the ordinary safe harbor compares current-year tax with the applicable percentage of prior-year tax. Prior-year return eligibility and adjusted gross income determine which comparison applies; withholding and timely estimated payments then establish whether each required installment is satisfied.
An estimated-tax safe harbor requires timely payments and can leave annual tax payable. Its annual comparison uses tax after applicable credits. The prior-year input is the relevant tax liability on a filed twelve-month return, before withholding or estimated payments.
The higher-income test is a fixed threshold:
Ordinary calendar-year installments generally equal one-fourth of the required annual payment. Their deadlines are April 15, June 15, September 15, and January 15 of the following year.
The installment analysis preserves these timing rules:
Common mistakes
- Taxing everything at the top rate. Example 1’s unsupported shortcut gives $80,000 x 22% = $17,600 instead of the graduated $12,312.
- Including retirement income in investment income. In Example 4, taxing the distribution itself produces $10,000 x 3.8% = $380; the supported NIIT is $190.
- Ignoring the fractional increment. Truncating Example 12’s 25.4 increments to 25 produces $4,400 - 25 x $50 = $3,150, overstating the credit by $50.
Bottom line
- Ordinary tax uses graduated brackets, while qualified dividends and eligible net long-term gains stack above ordinary taxable income.
- Nonrefundable credits reduce eligible tax within their limitations; refundable credits can generate an overpayment.
- Unused nonrefundable credits follow credit-specific carryover rules.
- NIIT equals 3.8% of the smaller positive investment-income base or positive MAGI excess.
Exam shortcut
Identify whether the question asks for regular income tax, total tax liability, or the balance due. Build the schedule through that requested endpoint. Mark qualified dividends and completed net long-term gains before selecting rates. Compute the ordinary layer first, then measure remaining preferential-band space. For a retirement distribution, make two separate checks: whether it raises MAGI and whether an early-distribution exception applies.
The full lesson (about 13,614 words, 91 min read) adds 19 worked examples, all 6 common mistakes, a self-check, free in the app.
Learning objectives
- IV.F1
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