Simple answer: if she will owe less than $1000 federal and $500 state (amount varies-check your state's requirement), she doe not need to do estimates.
You should pay in quarterly estimated taxes if you don't have enough withholding taken out to cover the tax on all your income.
You should make estimated tax payments for the current tax year if both of the following apply:
- 1. You expect to owe at least $1,000 in tax for the current tax year, after subtracting your withholding and credits.
- 2. You expect your withholding and credits to be less than the smaller of: 90% of the tax to be shown on your current year’s tax return, or 100% of the tax shown on your prior year’s tax return. (Your prior year tax return must cover all 12 months.)
