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Quarterly estimated tax

What should each remaining estimated payment be, and what does safe harbor require?

Your numbers

Next payment on current-year estimate

$12,000

Tax still due this year$36,000
Safe-harbor target$44,000
Safe-harbor remaining$32,000
Safe-harbor payment if split equally$10,667

Tip. Educational estimate with the assumptions listed on this page. Not tax, legal, or investment advice.

Assumptions

  • This is a cash plan, not Form 2210 annualization.
  • High-income safe harbor is modeled as 110% of last year's tax when the toggle is 1.
  • Penalties, state estimates, and household employment tax are excluded.

Explore the numbers

Examples

Load a scenario, then change one input at a time.

Example 1

Behind after Q1

$12k in, three payments left.

Next payment on current-year estimate

$12,000

Example 2

Caught up

Withholding already covers most of it.

Next payment on current-year estimate

$3,000

Example 3

New 1099 year

Last year was small; current year is not.

Next payment on current-year estimate

$15,000

What this calculates

Split remaining federal tax across the payments you still have to make, and compare that plan to last year's safe-harbor target.

How to use it

  1. Update the annual estimate whenever profit or withholding changes.
  2. Count only payments still ahead of you, including the next due date.
  3. If income is lumpy, compare this with a CPA annualized method.

Common mistakes

  • Ignoring withholding, which is treated as paid evenly.
  • Using four payments when Q1 already passed.
  • Assuming safe harbor equals what you will actually owe.

Formula

Remaining tax = annual estimate − already paid. Payment = remaining tax ÷ remaining payments. Safe harbor = last year × 100% or 110%.

FAQ

Should I use safe harbor or the current-year number?

Safe harbor is the simpler penalty floor. Pay the higher of a realistic current-year remainder and the safe-harbor remainder if you want margin.

Who uses 110%?

Higher AGI filers often must use 110% of last year's tax. Set the toggle to 1 if that is you.

Does this include SE tax?

Only if you put it in the annual estimate. Pair with the self-employment tax reserve tool.

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