Quarterly payments with side income

The Tax Alarm shows this view when you have side or self-employment income it counts and your withholding for the year covers less than 90% of the federal tax Countorra calculates. It says either "You're on track for the safe harbor amount" or "You're $X short for the next quarterly payment", with the date it's due.

The safe harbor is the smaller of 90% of this year's tax and 100% of last year's (110% when last year's AGI was over $150,000, or $75,000 if you're married filing separately). Paying it in four equal parts by April 15, June 15, September 15 and January 15 avoids the IRS underpayment penalty; a date that falls on a weekend or legal holiday moves to the next business day. Withholding counts as paid evenly through the year, and an estimated tax payment counts from the day you record it. If you'll owe less than $1,000 after withholding, nothing is required.

To use last year's figure, enter last year's total tax and AGI from your return (the return must cover a full 12 months). Until you do, the view uses 90% of this year's tax only, and says so. Clearing the total removes both.

It covers federal tax only. Countorra calculates; it doesn't make or file anything: you pay on IRS Direct Pay or EFTPS. The annualized income method, farming and fishing, and fiscal years aren't covered.