Safe Harbor Calculator
One number from last year's return, four penalty-proof payments. Find your safe harbor amount in seconds.
From last year’s Form 1040, the "total tax" line.
The federal income tax line on one pay stub. Skip this if you have no W-2 job.
$18,000 for the year, paid in four equal installments.
Pay these on time and you're protected from underpayment penalties, even if you owe more when you file. The IRS treats withholding as paid evenly through the year, so a full year of it counts.
This number could be lower. Check it against the annualized income method for free.
The safe harbor rule at a glance
Safe harbor is the rule that protects you from the underpayment penalty. Pay this much of last year’s tax, spread evenly across the four quarters, and the IRS won’t charge an underpayment penalty, even if you end up owing more this year. How much depends on last year’s income:
| Last year’s AGI | You must pay |
|---|---|
| $150,000 or less | 100% of last year’s total tax |
| Over $150,000 | 110% of last year’s total tax |
When safe harbor is not your lowest payment
Safe harbor looks backward. It protects you by charging you against last year’s numbers. If this year is going better than last year, that works in your favor. If this year is worse, or your income arrives unevenly, the IRS’s other method, the annualized income method, can require less because it follows what you actually earn each period.
Read the plain-English comparison in our guide, Safe harbor vs. annualized income, or let the full calculator run both methods on your real numbers and pick the smaller penalty-free payment for every quarter.
Frequently asked questions
This is just one piece
Get your complete quarterly estimate. Every income type, federal and state, penalties, and the method that pays the least, combined in one place.