Illinois Sales Tax on Materials Calculator
Calculate the total sales tax owed on construction materials purchased in Illinois, combining the state base rate with applicable county and city rates.
Formula
Taxable Base = Material Cost × (1 − Exempt% ÷ 100)
Combined Rate = Illinois State Rate (6.25%) + County Add-On Rate + City/Municipal Rate
Tax Amount = Taxable Base × (Combined Rate ÷ 100)
Total Cost = Taxable Base + Tax Amount
The same combined rate applies for Use Tax (35 ILCS 105) when materials are purchased outside Illinois for use within the state, with a credit allowed for sales tax legally paid to the purchase state.
Assumptions & References
- Illinois base Retailers' Occupation Tax (ROT) rate on general merchandise (including building materials) is 6.25% — 35 ILCS 120/2; 86 Ill. Adm. Code 130.101.
- County and city Home Rule ROT rates are added on top of the state rate per 55 ILCS 5/5-1006 and 65 ILCS 5/8-11-1.
- Building materials are classified as tangible personal property and are fully taxable at point of sale unless a specific exemption applies (e.g., resale, government contract, qualifying enterprise zone).
- Contractors who purchase materials for lump-sum contracts are generally the end consumer and owe ROT/Use Tax on those materials — 86 Ill. Adm. Code 130.1940.
- Use Tax (35 ILCS 105) applies at the same combined rate when materials are sourced out-of-state; a credit is available for tax paid in the originating state.
- County rates shown are representative 2024 figures. Always verify current rates with the Illinois Department of Revenue (IDOR) and your local municipality.
- This calculator does not account for special district taxes (e.g., mass transit, park districts) which may add additional fractions of a percent in certain jurisdictions.