State Estimated Tax Calculator
How much state tax to set aside each quarter on freelance, rental or investment income that has no withholding.
About State Estimated Tax Calculator
State Estimated Tax Calculator — works out how much state tax to set aside on income with no withholding. Estimated tax is what you pay yourself on income nobody withholds from: freelance work, rent, interest, dividends, capital gains, a side business. This applies the state income-tax rate to that income and shows the amount to set aside, with the remainder as what is genuinely yours to spend. States generally run the same four-instalment calendar as the IRS and charge interest on an instalment that falls short, so the useful number is the one you can put away each quarter rather than the annual total. Only the state component is calculated here; the federal part is separate and usually larger.
Formulas
Estimated state tax
Estimated state tax = untaxed income × state rate
Estimated net
Estimated net = untaxed income - estimated state tax
Worked example
With the default values below, State Estimated Tax Calculator returns State Tax to Set Aside of $495.00. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Stateone of Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming
- Illinois
- Your state tax rateaccepts 0–60
- Income with no withholdingminimum 0
- 10,000
Results
- State Tax to Set Aside
- $495.00
- Amount After State Tax
- $9,505.00
- State
- Illinois
- State rate used
- 4.95% (verified)
- Tax year
- 2026
- Source
- https://tax.illinois.gov/research/taxrates/income.html
Step by step
- 1Values used
- 2Estimated state tax
- 3Estimated net
- 4State Tax to Set Aside= 495.00
- 5Amount After State Tax= 9,505.00
- 6State= Illinois
- 7State rate used= 4.95% (verified)
- 8Tax year= 2026
- 9Source= https://tax.illinois.gov/research/taxrates/income.html
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
- State component only and an estimate. Federal income tax, FICA and any local tax are not included.
- This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
State component only and an estimate. Federal income tax, FICA and any local tax are not included.
Frequently Asked Questions
When are state estimated payments due?
Most states follow the federal quarterly calendar, but not all of them, and a few have different instalment percentages. Check your state revenue department's payment voucher instructions for the dates that apply to you.
What happens if I underpay?
States charge interest, and often a penalty, on the shortfall of each instalment rather than on the year as a whole, so paying a large amount in the final quarter does not undo an earlier gap. Many states waive the charge if you paid at least as much as your previous year's liability.
What income types trigger state estimated tax requirements?
Any income not subject to withholding: self-employment earnings, rental income, interest, dividends, capital gains, royalties, alimony received, and gambling winnings. If you expect to owe $500 or more in state tax after withholding and credits, most states require quarterly payments.
Can I use last year's tax as a safe harbor for this year's estimated payments?
Many states offer a safe harbor: if you pay 100% of last year's state tax liability (or 110% for higher earners), you avoid underpayment penalties even if this year's tax is higher. Check your state's specific rules - some require 90% of current year tax instead.
Why does it say the rate is not verified for my state?
For estimated tax, the old per-state page carried a flat rate that either could not be matched to a current revenue department publication, or the state uses a graduated schedule that a single rate cannot represent. Rather than show a number with no provenance, the calculator asks you for the rate from your own notice or return and then uses exactly that.
How do I use my own rate for estimated tax?
Type your estimated tax rate into the state rate field. Anything you enter wins over the built-in rate, and the result panel then labels the rate as yours rather than verified. Clearing the field goes back to the verified rate. A rate of 0 counts as blank, so to model a state with no income tax select one that has a verified 0%.
Which tax year does the estimated state rate belong to?
The result panel prints the tax year for the estimated rate. Each verified rate is stored with the tax year it was published for and a link to the page it was read from, so you can check it before relying on the figure. Unverified states show neither, because there is nothing to show.