Individuals, including sole proprietors, partners, and S corporation shareholders, generally use Form 1040-ES (PDF), to figure estimated tax.
To figure your estimated tax, you must figure your expected adjusted gross income, taxable income, taxes, deductions, and credits for the year.
When figuring your estimated tax for the current year, it may be helpful to use your income, deductions, and credits for the prior year as a starting point. Use your prior year’s federal tax return as a guide. You can use the worksheet in Form 1040-ES (PDF) to figure your estimated tax. You need to estimate the amount of income you expect to earn for the year. If you estimated your earnings too high, simply complete another Form 1040-ES worksheet to refigure your estimated tax for the next quarter. If you estimated your earnings too low, again complete another Form 1040-ES worksheet to recalculate your estimated tax for the next quarter. You want to estimate your income as accurately as you can to avoid penalties.
You must make adjustments both for changes in your own situation and for recent changes in the tax law.
Corporations generally use Form 1120-W (PDF), to figure estimated tax.