Quarterly Estimated Tax Calculator
See your estimated quarterly tax payment and monthly set-aside target.
Selected state
California
State
California
Estimated quarterly payment
$5,059.14
Estimate per quarter
Quarterly estimate
$5,059.14
Monthly set-aside
$1,686.38
Effective tax rate
27.0%
Percent of net business income
Tax breakdownOpen details+
| Gross self-employed income | $90,000.00 |
| Business expenses | -$15,000.00 |
| Net business income | $75,000.00 |
| SE Social Security portion | $8,588.55 |
| SE Medicare portion | $2,008.61 |
| Self-employment tax | $10,597.16 |
| Federal income tax | $6,504.31 |
| State income tax | $3,135.08 |
| Total estimated annual tax | $20,236.56 |
How to use this estimateOpen details+
- Enter projected yearly income and deductible business expenses.
- Review annual and quarterly tax estimates for planning.
- Set aside the monthly amount so quarterly deadlines are easier to manage.
Quarterly payments are a schedule, not four identical tax returns
Estimated tax is a way to prepay tax that is not covered by withholding. A simple annual estimate divided by four is a useful savings target when income is steady, but the IRS payment periods are not four equal three-month quarters. Uneven income may call for the annualized-income method instead.
The tool combines estimated self-employment, federal income, and state income tax, then shows both quarterly and monthly reserve amounts. Before paying, compare that projection with withholding from any W-2 job and with the prior-year safe-harbor thresholds that may reduce underpayment-penalty risk.
Worked example
$24,000 projected annual tax after withholding
- Quarterly planning amount: $24,000 ÷ 4 = $6,000.
- Monthly reserve target: $24,000 ÷ 12 = $2,000.
- Payments are matched to the IRS due dates rather than the last day of each calendar quarter.
Reforecast after a large contract, slow quarter, or change in W-2 withholding instead of relying on the original estimate all year.
Before you rely on the result
- Subtract expected withholding and refundable credits before calculating payments.
- Check whether the prior-year safe harbor produces a lower required payment.
- Use the annualized-income method when earnings are highly seasonal.
- Confirm federal and state due dates separately.
IRS estimated taxes guidanceOfficial rules, due dates, payment methods, and links to Form 1040-ES.