1040-ES safe harbor: $10,000 → $1,000/quarter
The estimated tax safe harbor (Form 1040-ES, IRC 6654) helps you avoid an underpayment penalty by paying at least 100% of last year’s total tax (110% if prior-year AGI was over $150,000), minus expected federal withholding, then dividing the remainder by 4.
This tool models only that 100%/110% prior-year harbor. It does not compute 90% of current-year tax, the MFS $75,000 AGI threshold, or farmer/fisherman rules. Educational estimate, not tax advice.
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This page is about U.S. IRC 6654 only. It is not Mexico, Guatemala, or Peru withholding.
rate = 100% (or 110% if prior-year AGI > $150,000)
required annual = prior-year total tax × rate
remaining = max(0, required annual − expected withholding)
quarterly = remaining / 4
Worked example: $10,000 → $1,000/quarter
Prior-year Form 1040 total tax: $10,000. Expected federal withholding this year: $6,000. Prior-year AGI was not over $150,000 (100% rate).
- Required annual: $10,000 × 1.00 = $10,000
- Still to pay via 1040-ES: $10,000 − $6,000 = $4,000
- Payment per quarter: $4,000 ÷ 4 = $1,000
If prior-year AGI was over $150,000, the rate is 110%: annual $11,000, remaining $5,000, quarterly $1,250.
| Prior-year tax | Expected withholding | AGI > $150k | Required annual | Per quarter |
|---|---|---|---|---|
| $5,000 | $2,000 | No | $5,000 | $750 |
| $10,000 | $6,000 | No | $10,000 | $1,000 |
| $10,000 | $6,000 | Yes (110%) | $11,000 | $1,250 |
| $20,000 | $0 | No | $20,000 | $5,000 |
| $10,000 | $10,000 | No | $10,000 | $0 |
100% vs 110%: when the harbor rises
| Condition | Harbor rate | With $10,000 prior tax |
|---|---|---|
| Prior-year AGI ≤ $150,000 | 100% | Annual $10,000 |
| Prior-year AGI > $150,000 | 110% | Annual $11,000 |
| Married filing separately (MFS) | $75,000 threshold | Not modeled here |
What is in scope
| Item | In this calculator? | Note |
|---|---|---|
| 100% of prior-year tax | Yes | Form default |
| 110% if AGI > $150,000 | Yes | Checkbox on the form |
| Minus expected federal withholding | Yes | W-2 / 1099 this year |
| 90% of current-year tax | No | Separate IRC 6654 path |
| MFS $75,000 AGI threshold | No | See IRS Pub 505 |
| Farmer/fisherman special rules | No | Out of scope |
Sources
Related: paycheck take-home, federal withholding, self-employment tax, W-4 Step 4.
IRC 6654: pay 100% of last year’s total tax, or 110% if AGI was over $150,000. With $10,000 prior tax and $6,000 withholding the quarter is $1,000 (100%) or $1,250 (110%).
No. Prior-year harbor only (100% or 110%). The current-year 90% path is not modeled. Educational estimate, not tax advice.
If expected withholding is greater than or equal to the required annual amount, remaining and quarterly are $0. Example: $10,000 prior tax and $10,000 withholding.
The MFS AGI threshold of $75,000 is not modeled. The $150,000 threshold here is educational only.