Transparent method
The formula
Worked example
Example inputs
How to interpret the result
Estimated tax is due across the year on a schedule, not as one lump sum at filing, and a period of unexpectedly high income partway through the year means the remaining quarterly payments need to catch up the underpayment, not just cover that quarter's income at the original pace.
Before you rely on it
What to check
Recalculate the remaining quarterly payments whenever income shifts meaningfully during the year, rather than dividing the annual estimate evenly and never revisiting it.
The common error
Where people go wrong with quarterly estimated tax calculator
Splitting an annual tax estimate into four equal payments made once at the start of the year and never adjusted. Income that runs higher or lower than projected changes what the remaining quarters actually need to cover.
Sensitivity evidence
How projected total annual tax changes the estimated payment per remaining quarter
| Projected total annual tax | Estimated payment per remaining quarter | Annual amount still due |
|---|---|---|
| $25,600 | $3,867 | $11,600 |
| $28,800 | $4,933 | $14,800 |
| $32,000worked example | $6,000 | $18,000 |
| $35,200 | $7,067 | $21,200 |
| $38,400 | $8,133 | $24,400 |
Every input, tested
Which input moves the estimated payment per remaining quarter most
| Input | Tested from | To | Estimated payment per remaining quarter at each end | Swing |
|---|---|---|---|---|
| Remaining quarterly payments | 2 | 4 | $9,000 to $4,500 | $4,500 (75%) |
| Projected total annual tax | $28,800 | $35,200 | $4,933 to $7,067 | $2,133 (36%) |
| Expected withholding and credits | $7,200 | $8,800 | $6,267 to $5,733 | $533 (8.9%) |
| Estimated payments already made | $5,400 | $6,600 | $6,200 to $5,800 | $400 (6.7%) |
Two variables at once
Estimated payment per remaining quarter by projected total annual tax and expected withholding and credits
| Projected total annual tax \ Expected withholding and credits | $6,400 | $8,000 | $9,600 |
|---|---|---|---|
| $25,600 | $4,400 | $3,867 | $3,333 |
| $28,800 | $5,467 | $4,933 | $4,400 |
| $32,000 | $6,533 | $6,000 | $5,467 |
| $35,200 | $7,600 | $7,067 | $6,533 |
| $38,400 | $8,667 | $8,133 | $7,600 |
Step by step
The worked example, input by input
| Input | Value used |
|---|---|
| Projected total annual tax | $32,000 |
| Expected withholding and credits | $8,000 |
| Estimated payments already made | $6,000 |
| Remaining quarterly payments | 3 |
| Estimated payment per remaining quarter | $6,000 |
| Annual amount still due | $18,000 |
Where the inputs come from
Projected total annual tax is your estimate of federal income tax plus self-employment tax for the year, which you can get from last year's return adjusted for changes or from a tax calculator. Expected withholding and credits covers tax withheld from any wages and credits you expect. Estimated payments already made counts prior installments, and remaining quarterly payments is how many are left. Due dates are in April, June, September and January.
When the result stops applying
Payments can be adjusted as the year goes on, and underpayment penalties depend on meeting safe harbors, which are based on the prior year's tax or a percentage of the current year's. State estimated taxes are separate. The estimate depends on income and deductions that may change, so review it each quarter. Late payments accrue interest and penalties.
What to compare it with
Find the safe amount with the tax safe harbor calculator, and see the tax itself on the self-employment tax, federal income tax and QBI deduction pages. The take-home pay and tax withholding calculators help if you also have wages. Paying through IRS Direct Pay avoids mailing checks.
People also ask
Frequently asked questions
When are quarterly estimated taxes due?
Generally April 15, June 15, September 15 and January 15 of the next year, shifting to the next business day if a date falls on a weekend or holiday.
Who has to pay estimated taxes?
People who expect to owe $1,000 or more after withholding and credits, such as freelancers, business owners and those with substantial investment income.
What if I underpay?
The IRS may charge an underpayment penalty, calculated as interest on the shortfall. Meeting a safe harbor avoids it.