You do not "have to". Essentially, it's optional for someone in your situation.
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 might be able to increase your W2 withholding, at
your regular job, to account for the extra 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.)
TurboTax (TT) can prepare the payment vouchers. In your 2016 software, enter at:
Federal Taxes or Personal (H&B version)
Other Tax Situations
Other Tax Forms
Form W-4 and Estimated Taxes - Click the Start or Update button
If your goal is just
to avoid the underpayment penalty, then paying 100% of the prior year tax
liability is the “safe haven”