Home Office Deduction Calculator 2026

How the home office deduction works

If you use part of your home regularly and exclusively for business, you can deduct a portion of your home costs against your Schedule C income. The deduction reduces both your federal income tax and your self-employment (SE) tax — making it one of the few write-offs that reduces both layers of tax at once.

The IRS offers two methods. You elect one on your tax return each year — you can switch methods from year to year with no penalty.

The regular and exclusive use test — the rule that disqualifies most people

To claim any home office deduction, the space must pass both tests under IRC § 280A:

• Regular use: You use the space for business on a regular basis — not just occasionally.
• Exclusive use: The space is used only for business. A spare bedroom that doubles as a guest room fails this test. A dedicated room with no personal furniture passes. A defined corner in a shared room is a gray area (many CPAs will allow a clearly delineated workspace).

There's also a principal-place-of-business test: the home office must be your principal place of business, or where you meet clients regularly, or a separate structure (like a detached studio). For most freelancers and solo practitioners who work from home, this is satisfied automatically.

Actual method: what you can include

The actual expense method allocates a portion of real home costs to business. The allocation percentage is typically: office sqft ÷ total home sqft (the area method, which IRS accepts and most CPAs use).

Indirect expenses — costs that benefit the whole home — are prorated at the business percentage:

• Rent paid (if renting), or mortgage interest (homeowners deduct interest, not principal)
• Utilities: electricity, gas, water, trash
• Homeowner's or renter's insurance
• HOA dues
• General home repairs and maintenance
• Home depreciation (39-year straight-line on the business-use portion — requires a basis calculation)

Direct expenses — costs that apply only to the office — are deductible at 100%:

• Painting or repairing the office room only
• Flooring installed only in the office

Which method saves more — and when

Use the calculator above for your specific numbers. In general:

• The simplified method maxes out at $1,500 — if your actual prorated expenses are higher, actual wins.
• The actual method wins when you have a large office in a high-cost home (high rent, mortgage interest, or utilities). Example: 400 sqft office in a 1,600 sqft home = 25% business use × $36,000 annual costs = $9,000 deduction vs. $1,500 simplified.
• The simplified method wins when your home costs are low (small apartment, paid-off home, low utilities) or when your office is small. Example: 150 sqft office in a 2,000 sqft home = 7.5% × $20,000 = $1,500 — same as simplified, but without Form 8829 complexity.
• Renters often benefit significantly from the actual method, since rent is fully prorated (no depreciation recapture issue on a rented home).

How the home office deduction reduces your SE tax — not just income tax

This is the home office deduction's underappreciated benefit. Unlike many above-the-line deductions, the home office reduces your Schedule C net profit — which is also the base for self-employment tax. Every dollar of home office deduction reduces:

1. SE tax by roughly 14.1 cents (=$1 × 92.35% × 15.3%, if under the $184,500 SS wage base)³
2. Federal income tax by your marginal rate on the remaining reduction

At a 24% marginal rate, a $5,000 home office deduction is worth approximately $1,908 in combined tax savings ($705 SE tax + $1,203 income tax). At 35%, it's approximately $2,455. This is why even the $1,500 simplified-method max saves meaningful money, and why maximizing it with the actual method is worth the paperwork for high-earners with large home costs.

S-corp owners: use an accountable plan, not Form 8829

If you've elected S-corp status, you cannot claim a home office deduction on Schedule C — you don't file one. As an employee of your S-corp, your home office must be reimbursed through an accountable plan instead. The plan reimburses you for the business-use percentage of your actual home expenses (just like the actual method calculus above), which becomes a deductible expense for the S-corp and is non-taxable to you as an employee.

See: S-Corp Accountable Plan Guide → — includes setup steps, mileage and home-office reimbursement templates, and interaction with your W-2 and solo 401(k).

Common mistakes to avoid

• Including mortgage principal in actual expenses. Only mortgage interest is an indirect expense. Principal repayment has no deductibility here (it builds equity).
• Claiming internet as a home office indirect expense. Internet used for business is a 100% deductible business expense on its own line — it doesn't need to run through Form 8829.
• Mixing simplified and actual in the same year. You pick one method per tax year. You can switch next year.
• Using the wrong sqft for the simplified method. The simplified cap is 300 sqft — even if your office is 400 sqft, you can only use 300. The actual method has no sqft cap.
• Forgetting the gross income limitation. With the actual method, your home office deduction cannot exceed your net income from the business (before the deduction). Excess carries forward to future years.

1. Home office simplified method — $5 per square foot, maximum 300 square feet ($1,500 max): IRS Simplified Option for Home Office Deduction · IRS Topic No. 509, Business Use of Home. Rate unchanged for 2026 per IRS Rev. Proc. 2013-13.
2. Actual expense method — Form 8829 and deductible indirect/direct expenses: IRS Form 8829 Instructions · IRS Pub. 587, Business Use of Your Home. Mortgage interest (not principal) and rent are deductible indirect expenses prorated by business-use percentage.
3. 2026 SE tax rate (15.3% on net SE income up to $184,500 SS wage base, then 2.9% Medicare): IRS Topic No. 554, Self-Employment Tax · SSA Contribution and Benefit Base 2026. Net SE income = gross × 92.35%.
4. 2026 standard deduction ($16,100 single / $32,200 MFJ) and federal income tax brackets: IRS 2026 Inflation Adjustments · Tax Foundation 2026 Brackets. Values per IRS Rev. Proc. 2025-32.

Tax values verified as of May 2026. IRC § 280A governs home office deductibility.