Illinois (IL) Home Office Deduction Calculator
Tax year: 2026 · Figures for Tax Year 2026 · Source: IRS
Built and audited by the CalcSumly Engineering Team using official IRS and State Department of Revenue data.
Your Schedule C net profit before the home office deduction.
Square footage of your dedicated, exclusively-business workspace.
Total square footage of your home.
Rent or mortgage interest, utilities, insurance, and repairs.
Simplified method
$750
$5/sqft × 150 sqft · 2026
Actual method
Recommended$1,800
10.0% of home × expenses · 2026
How the Illinois (IL) home office deduction calculator works
This calculator estimates your total tax savings from the home office deduction in Illinois for 2026. It computes tax at your current net profit, then again at net profit minus the deduction, and reports the difference across three tax layers:
- SE tax savings. The deduction reduces Schedule C net profit before SE tax is calculated. SE tax is 15.3% on 92.35% of net profit (Social Security 12.4% capped at $184,500, plus Medicare 2.9% uncapped). A $1,500 deduction saves roughly $212 in SE tax regardless of state.
- Federal income tax savings. Lower net profit reduces both the deductible half of SE tax and federal AGI, which cascades into lower federal taxable income. At the 22% bracket, a $1,500 deduction saves roughly $307 in federal income tax.
- Illinois state income tax savings. Illinois taxes federal AGI minus the state standard deduction, so both the simplified and actual home office methods reduce IL taxable income automatically.
Two IRS methods compared
- Simplified method (Rev. Proc. 2013-13). $5 per square foot of dedicated office space, up to 300 sqft, maximum $1,500.
- Actual expense method (IRS Form 8829). Multiply business-use percentage by your actual home costs: rent or mortgage interest, utilities, insurance, and repairs. Illinois recognises this method, so IL state income tax savings are included.
Scope and limitations
Excluded: Excludes Illinois local taxes and the 1.5% Personal Property Replacement Tax (PPRT) that applies to S-Corps and partnerships at entity level. SDI is not applicable in Illinois. Age-related additional exemption ($1,000 per qualifying condition) is excluded. This calculator models a single Schedule C filer with no other income. It excludes home depreciation recapture, the 20% QBI deduction, health insurance deductions, and tax credits. Consult a tax professional before filing.
Data sources: Federal figures from IRS Rev. Proc. 2013-13, IRS Publication 587, and IRS Rev. Proc. 2025-32. Illinois income tax figures verified against the Illinois Department of Revenue for Tax Year 2026.
Sources
- IRS Rev. Proc. 2013-13 — Simplified Method ($5/sqft, 300 sqft max)
- IRS Publication 587 — Business Use of Your Home
- IRS Form 8829 Instructions — Actual Expense Method
- IRS Rev. Proc. 2025-32 — 2026 Standard Deduction Amounts
- IL Dept. of Revenue — Income Tax Rates (4.95% flat rate)
- IL Dept. of Revenue — What is the Illinois exemption allowance? ($2,925 per exemption, 2026)
Frequently asked questions
Does Illinois conform to the home office deduction?+
Yes. Illinois uses federal AGI as its starting point and applies a flat 4.95% rate. Since Schedule C home office deductions reduce federal AGI before Illinois tax is calculated, both the simplified and actual methods reduce Illinois taxable income. A $1,500 simplified deduction saves roughly $69 in Illinois income tax.
What is Illinois's income tax rate for home office savings?+
Illinois has a flat 4.95% individual income tax rate (stable since 2017). Every dollar of home office deduction that flows through to Illinois taxable income saves 4.95 cents. Illinois also allows a personal exemption credit of $2,925 (2026), which reduces the tax bill by a fixed amount rather than a percentage.
What is the home office deduction?+
The home office deduction (IRC §280A) lets self-employed people deduct the cost of a dedicated workspace in their home. The space must be used regularly and exclusively for business. The deduction is taken on Schedule C, which reduces net self-employment profit and therefore lowers SE tax, federal income tax, and most state income taxes.
What is the simplified method?+
The IRS simplified method (Rev. Proc. 2013-13) lets you deduct $5 per square foot of your home office, up to 300 square feet, for a maximum annual deduction of $1,500. No receipts, depreciation schedules, or Form 8829 are needed. The $5/sqft rate is statutory and has not changed since 2013.
What is the actual expense method?+
The actual method computes your business-use percentage (office sqft divided by total home sqft) and applies it to your actual home costs: rent or mortgage interest, utilities, insurance, and repairs. You claim this on IRS Form 8829. The actual method often yields a larger deduction than the simplified method for those with high home expenses.
Does the home office deduction reduce self-employment tax?+
Yes. The deduction is claimed on Schedule C, which reduces net profit before SE tax is calculated. Because SE tax is 15.3% on 92.35% of net profit, a $1,500 deduction saves roughly $212 in SE tax at any income level below the Social Security wage base ($184,500 for 2026).
What qualifies as a home office?+
The space must be used regularly and exclusively for business (IRC §280A(c)(1)). A dedicated room or partitioned area qualifies. It cannot double as a personal space or guest room. You do not have to use it every day, but it must be your principal place of business or a place where you regularly meet clients.
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