The Illinois Sales Tax Calculator lets you quickly work out the exact amount of sales tax on any purchase in Illinois — and reverse-calculate the pre-tax price from a receipt total. Just enter your amount, choose your city or county from the preset list, and the calculator shows you the full breakdown: Illinois state tax, local tax, combined rate, and the final total.
How it works
Illinois has a two-layer sales tax structure. The state charges a flat 6.25% general merchandise rate, set by the Illinois Department of Revenue (IDOR). On top of that, local governments — counties, cities, transit authorities, and special districts — stack their own rates.
Add-tax mode (pre-tax to total)
You enter the net (pre-tax) price, for example $75.00. The calculator multiplies it by the combined rate:
total tax = net price x combined rate
total = net price + total tax
At a 10.25% Chicago rate, a $75.00 item carries $7.69 in total tax, making the total $82.69 — broken down as $4.69 state tax (6.25%) and $3.19 local tax (4.25%, rounding to nearest cent).
Reverse (back-out) mode — total to pre-tax
You enter the amount you actually paid at the till (tax already included). The calculator divides by (1 + combined rate):
pre-tax amount = total paid / (1 + combined rate)
This is the standard algebraic reverse — useful when you have a receipt and need to separate the net price from the tax for accounting, reimbursement, or expense-reporting purposes.
Illinois sales tax rates at a glance
The state base rate is 6.25%, fixed statewide. Local additions vary widely:
| Area | State | Local | Combined |
|---|---|---|---|
| Chicago (Cook Co., city) | 6.25% | 4.25% | 10.25% (approx.) |
| Peoria | 6.25% | 2.50% | 8.75% |
| Springfield | 6.25% | 2.00% | 8.25% |
| Naperville (DuPage Co.) | 6.25% | 0.75% | 7.00% |
| Statewide average | 6.25% | ~2.61% | ~8.86% |
Rates in the table are approximate and rounded for display. Your exact rate depends on your precise address — always confirm at tax.illinois.gov or via the MyTax Illinois portal before filing or quoting a formal price.
Worked example
You buy office supplies in Chicago for a combined total of $218.97 on the receipt. What was the pre-tax price, and how much tax did you pay?
- Combined rate in Chicago: 10.25% (6.25% state + 4.25% local)
- Pre-tax amount: $218.97 divided by 1.1025 equals $198.61
- Total tax: $218.97 minus $198.61 equals $20.36
- State portion (6.25%): $12.41
- Local portion (4.25%): $8.44 (rounded to nearest cent)
Switch the calculator to “Back out tax”, type $218.97, select the Chicago preset, and you get the same numbers instantly.
Note on food and medicines
Illinois taxes qualifying groceries and qualifying drugs at 1% state rate rather than 6.25%. Local rates may still apply on top. This calculator defaults to the 6.25% general merchandise rate. For reduced-rate purchases, set the local rate field to adjust the combined total accordingly, or consult the Illinois Department of Revenue guidance for the precise applicable rate.
All calculations run entirely in your browser — no figures are ever sent to a server or stored anywhere.