Three qualifying tests

You qualify for a home-office deduction if you use part of your home (1) regularly and exclusively (2) as your principal place of business, OR as a place to meet clients in the normal course of business, OR as a separate structure used in your trade or business. Daycare providers may meet the regular-use test without exclusive use under a special rule.

Principal place of business

Your home office qualifies as a principal place of business if you use it exclusively and regularly for administrative or management activities of your trade or business AND you have no other fixed location where you conduct substantial administrative activities. This rule (Section 280A(c)(1)) saved the deduction for many service professionals after the unfavorable 1993 Soliman decision.

Calculating the deduction

Compute business-use percentage by dividing the area used regularly and exclusively for business by the total area of the home. Apply that percentage to indirect expenses (utilities, insurance, depreciation, mortgage interest, real estate taxes). Direct expenses (painting only the office) are 100% deductible.

Simplified method

Instead of calculating actual expenses on Form 8829, you may elect a $5-per-square-foot deduction (300 sq ft cap, $1,500 maximum) directly on Schedule C line 30. The simplified method skips depreciation (and recapture), but mortgage interest and real estate taxes still go on Schedule A.

Loss limitation

The home-office deduction cannot create or increase a Schedule C loss. Excess expenses carry over to future years under the actual-expense method, but not under the simplified method.

How to find what you need quickly

Reading an IRS publication straight through is rarely the right move; using it as a reference is. Open the PDF, jump to the table of contents, identify the chapter that matches your facts, and skim the worked examples at the end of that chapter first — they usually answer 80% of practical questions. The detailed rules in the body of the chapter then make sense in the context of an example. The publication's index, while less polished than a commercial tax-research database, is searchable in any PDF reader with Ctrl+F and surfaces the exact paragraph you need in seconds.