The general rule is that you must make estimated tax payments:
If you expect to owe at least $1,000 after subtracting your withholding and credits when you file your return for this year, and
You expect your withholding and credit for this year to be less than the smaller of::
90% of the tax you expect to report when you file your return this year, or
100% of the tax shown on your return from last year
If your main source of income is your salary or wages, and you see that not enough tax is being withheld, you may want to give your employer a revised W-4 Form.
Married Taxpayers
If you are married, you and your spouse can make joint estimated tax payments. Making joint estimated payments does not affect your choice on how you want to file your return at the end of the year. You can still file either as married filing jointly, or married filing separately.
If you plan to file a joint return this year, but filed separate returns last year, for purposes of the general rule on estimated payments, your tax for last year is the total of the tax reported on your separate returns from last year, whether you filed as single, head of household, or married filing separately.
If you plan to file separately this year, but filed jointly last year, each spouse would consider his or her share of the total joint tax from last year. To distribute the joint tax from last year, you would each calculate how much your tax would have been if you had filed separate returns last year, based on the separate filing status you plan to use this year. You would then add these two amounts together to determine how much total tax you would have paid if you had both filed separately last year. Each spouse would then calculate his or her proportionate share, and this would be the amount of tax from last year for purposes of the general rule for paying estimated tax this year.
Special Rules
For taxpayers who receive at least two-thirds of their income from farming or fishing, the general rule of 90% of the expected tax for this year is replaced by 66 2/3%. For higher income taxpayers, whose adjusted gross income from last year was over a certain amount (published by the Internal Revenue Service (IRS) each year in Publication 505, Tax Withholding and Estimated Tax), the 100% of last year’s tax requirement is replaced with 110%.