Illinois Capital Gains Tax Calculator 2026

The Illinois Capital Gains Tax Calculator is a free, browser-based tool that estimates the combined federal and Illinois tax on a realised gain from selling stock, property or a business interest. Illinois has no separate capital gains rate, so gains are taxed as ordinary state income on top of the federal long or short-term rate. Nothing you enter leaves your browser.

Illinois Capital Gains Tax Rules

Illinois has no separate capital gains rate. Short-term and long-term gains are both taxed as ordinary income at Illinois's flat 4.95% rate. This state tax is separate from — and in addition to — the federal capital gains tax you owe to the IRS.

Understanding Illinois's capital gains rules is essential for investors, homeowners selling property, and business owners who plan to sell assets. The calculator above computes your estimated federal and Illinois state capital gains tax based on your sale price, cost basis, holding period, and income. It subtracts the 2026 federal standard deduction ($16,100 single, $32,200 married filing jointly, $24,150 head of household) from the income you enter, stacks the gain on top of your other income, and taxes each slice at its own rate.

Federal vs Illinois Capital Gains Tax

The federal tax on a gain depends on your taxable income and on how long you held the asset. For long-term gains (held more than 12 months), the 2026 federal rates set by IRS Rev. Proc. 2025-32 are 0% on taxable income up to $49,450 single / $98,900 married filing jointly / $66,200 head of household, 15% up to $545,500 single / $613,700 joint / $579,600 head of household, and 20% above those thresholds. The gain is stacked on top of your other income, so one sale can be taxed partly at 0%, partly at 15% and partly at 20%. Short-term gains are taxed as ordinary income at the 2026 federal brackets of 10% to 37%. A 3.8% Net Investment Income Tax is added on the lesser of the gain or the amount by which your modified adjusted gross income exceeds $200,000 (single or head of household) or $250,000 (married filing jointly).

Worked example (2026): a single filer with $90,000 of other income sells stock held for two years at a $50,000 gain. Federal tax is $7,500 (the whole gain falls in the 15% band) and Illinois tax is $2,475, a combined $9,975 or 20.0% of the gain. Sold after 11 months instead, the same gain is short-term: $11,364 federal plus $2,475 Illinois tax, $13,839 in total. The calculator above reproduces both results.

Illinois Cap Gains Strategies & Exemptions

Several strategies can help Illinois taxpayers reduce their capital gains tax burden. First, hold assets for more than 12 months to qualify for the lower long-term federal rate. Second, harvest capital losses to offset gains — if you have losing positions, selling them in the same tax year can reduce your net taxable gain. Third, use tax-advantaged accounts (401k, IRA, HSA) to shelter future investment growth from both federal and Illinois state tax.

For Illinois homeowners, the federal home-sale exclusion allows you to exclude up to $250,000 (single) or $500,000 (married filing jointly) of gain from the sale of a primary residence, provided you meet the 2-of-5-year ownership and use tests. The calculator does not apply this exclusion, so enter only the gain that remains after it. Consult an Illinois tax professional to understand which exclusions apply to your specific situation.

Always work with a qualified tax professional before executing large asset sales. Tax laws change, and individual circumstances — such as installment sales, like-kind exchanges (1031 exchanges for real estate), or business asset sales — can significantly affect your total tax liability.

Short-Term vs Long-Term: The Holding Period Is the Only Lever That Changes the Federal Rate

Illinois taxes a gain the same way whichever you hold, so the entire rate difference sits on the federal side and it is decided by one date. An asset held for one year or less produces a short-term gain taxed at your ordinary federal income rate; held for more than one year it becomes long-term and moves onto the lower long-term capital gains brackets. The clock starts the day after you acquire the asset and ends on the day you dispose of it, which is why a sale a few days early can cost a meaningful amount of tax on an otherwise identical trade. Two details trip people up. Inherited assets are treated as long-term regardless of how briefly you held them, and they also take a stepped-up basis at the date of death. Gifted assets do the opposite: you inherit the giver's holding period and their original basis, so a long-held gift can be sold immediately at long-term rates. The IRS sets out the holding-period rules and the current long-term brackets in its capital gains guidance at irs.gov Topic 409. Before selling near the one-year mark, check the acquisition date on the trade confirmation rather than memory. Updated 2026-09-15.

Offsetting an Illinois Gain: Loss Harvesting, Carryforwards and the Wash Sale Trap

Capital losses reduce capital gains dollar for dollar before any rate is applied, and because Illinois starts from federal adjusted gross income, harvesting a loss lowers the state bill as well as the federal one. The netting order matters: short-term losses first offset short-term gains and long-term losses offset long-term gains, with any remainder crossing over. If losses exceed gains, a limited amount can be deducted against ordinary income each year and the rest carries forward indefinitely until it is used. The trap is the wash sale rule, which disallows the loss if you buy the same or a substantially identical security within thirty days before or after the sale — including a purchase in your spouse's account or an IRA, where the loss is not merely deferred but permanently lost. Selling a broad index fund and buying a different index tracking a different benchmark generally keeps you invested without triggering it, while selling and rebuying the identical fund does not. Run the calculator on the net figure after losses rather than the gross gain, since that is what both the federal and Illinois calculations actually tax.

Chicago & Cook County Home Sales — Illinois Transfer Taxes That Reduce Your Net Gain

Illinois has one of the highest cumulative transfer-tax stacks in the country, and it directly reduces the gain amount you actually pocket after a sale — a factor most cap-gains calculators skip. Per the official Illinois Department of Revenue Real Estate Transfer Tax page, sellers of Illinois real estate pay the state transfer tax of $0.50 per $500 of consideration ($1.00 per $1,000 = 0.10%). On top of that: Cook County adds $0.25 per $500 (0.05%) and Chicago city adds a graduated transfer tax that ranges from $5.25 per $500 on the first $1M of price to as high as $15 per $500 on the portion above $1.5M under the "Bring Chicago Home" ordinance (implementation delayed pending litigation but scheduled for reintroduction). For a $600,000 Chicago home sale, transfer taxes alone total roughly $6,900-$7,500 — money that comes out of gross proceeds BEFORE you compute your gain for federal + 4.95% state cap gains tax. Save the transfer-tax closing-statement line item and add it to your cost basis when calculating gain — this is a common CPA miss that costs Illinois sellers hundreds in overpaid tax.

Selling Your Illinois Home: the Federal Exclusion Cuts the Illinois Bill Too

Illinois starts its calculation from your federal adjusted gross income, which has a consequence worth real money on a house sale: a gain excluded at the federal level under the primary-residence rules never reaches the Illinois return either. Meet the ownership and use test — owned and lived in the home as your main residence for two of the five years before the sale — and the excluded portion of the gain is outside the 4.95% state tax as well as outside federal tax. Only the gain above the exclusion flows through to both. This is why the calculator's result can drop to zero on a home sale that looks large on paper, and why keeping receipts for capital improvements matters: they raise your basis, shrinking the taxable slice on both returns. The ownership and use test is set out in IRS Topic No. 701, Sale of Your Home. Updated 2026-09-25.

When an Illinois Gain Forces a Quarterly Estimated Payment

Illinois does not withhold tax on a capital gain, so a large sale can leave you underpaid for the year and facing a penalty even though you pay in full at filing. Illinois expects estimated payments through form IL-1040-ES when you will owe more than a modest amount beyond withholding, and the federal side has its own parallel requirement. The practical move after a big sale is to make an estimated payment in the quarter the gain was realised rather than waiting for April — penalties are charged by quarter, so a payment in January does not cure an underpayment from a June sale. Take the state figure from the calculator above as the minimum to set aside, and add the federal line for the full amount. Estimated payment rules are published by the Illinois Department of Revenue. Updated 2026-09-25.

Last updated: October 2026. Federal figures: IRS Rev. Proc. 2025-32 (2026 capital gains thresholds, brackets and standard deduction), IRS Topic 409 and IRS Topic 559 (Net Investment Income Tax). Illinois: Illinois income tax calculator (same 2026 state rules).