What expenses can a law firm or consulting firm deduct for a home office?

The space has to meet two IRS tests before anything is deductible. It must be used regularly for business, and it must be used exclusively for business. A spare bedroom where you meet clients and do legal research every day qualifies. The dining room table where you sometimes review contracts does not. The exclusive use requirement is strict. If your kids do homework in that room on weekends, the IRS considers that mixed use and the deduction disappears.

For law firms and consulting firms, the home office often serves as the principal place of business or a location where you meet clients. Either qualifies. If you also rent a separate office but maintain a dedicated home office where you handle substantial administrative or management work, that can qualify too.

Once you’ve established the space qualifies, you choose between two calculation methods.

The simplified method gives you $5 per square foot up to 300 square feet. That’s a maximum deduction of $1,500 per year. It requires minimal recordkeeping and works fine for a modest spare room. Many consultants working from home find this is the easier path.

The actual expense method typically produces a larger deduction, especially in Northern Virginia where housing costs are high. You calculate the percentage of your home used for business (usually office square footage divided by total home square footage) and apply that percentage to your actual housing expenses. Those expenses include mortgage interest or rent, property taxes, homeowners insurance, utilities, internet, repairs, and depreciation on the home itself. A 200 square foot office in a 2,000 square foot home means 10% of those costs are deductible. When your mortgage interest alone runs $30,000 a year, that 10% adds up quickly.

Here is where entity structure changes everything. If you operate as a sole proprietor or single-member LLC, you claim the home office deduction directly on Schedule C. Straightforward.

If your law firm or consulting practice is structured as an S-Corp, you cannot take a home office deduction on your personal tax return. Instead, the S-Corp must reimburse you through what’s called an accountable plan. You submit documentation of your home office expenses to the corporation, the corporation reimburses you, and the corporation deducts that reimbursement as a business expense. The reimbursement is not taxable income to you. Skip this step or handle it informally and you either lose the deduction entirely or create a taxable event. Many professional service firm owners structured as S-Corps miss this distinction and either claim the deduction incorrectly or don’t claim it at all.

Your bookkeeping needs to support whichever method you choose. For the actual expense method, that means tracking every utility bill, insurance payment, and repair cost throughout the year and calculating the business-use percentage consistently. For S-Corp accountable plans, the reimbursement needs to show up in the company’s books as a documented expense with supporting records. Sloppy recordkeeping here is what turns a legitimate deduction into an audit problem.

The home office deduction is real money for attorneys and consultants working from home, whether full-time or in a hybrid arrangement. But the rules around qualification, method selection, and entity-specific compliance mean it has to be set up correctly from the start. If you’re unsure how your firm should handle it, working with Northern Virginia small business bookkeeping professionals who understand professional service firms can help you structure the deduction properly and keep the documentation current all year long.