How to Fill Out and File Form 8829: Home Office Deduction

To fill out Form 8829, you calculate your home’s business-use percentage in Part I, list your direct and indirect home expenses in Part II and apply the gross income limitation, figure depreciation on the business portion of the home in Part III if you own it, and carry any unallowed amounts forward in Part IV. The final number on Line 36 moves to Line 30 of your Schedule C, where it reduces your self-employment income.¹

Before You Start: Who Can File and What Qualifies

Form 8829 is filed by self-employed people who file a Schedule C: sole proprietors, freelancers, and independent contractors. W-2 employees cannot use it. The Tax Cuts and Jobs Act suspended the unreimbursed employee expense deduction starting in 2018, and the One Big Beautiful Bill Act signed on July 4, 2025 made that elimination permanent for the 2026 tax year and beyond.²

Under IRC Section 280A, the space you claim must pass two tests at the same time: exclusive use and regular use.³ Exclusive use means the area is used only for business. No kids doing homework at the desk, no personal browsing on the office computer. Regular use means you actually work there on an ongoing basis.

Your home also has to fit at least one of these categories:

Your principal place of business, including a home used for administrative or management activities when you have no other fixed location for that work.
A place where you regularly meet patients, clients, or customers.
A separate structure on the property used exclusively and regularly for business.

Two narrow exceptions bend the exclusive use rule. If your home is your only fixed business location, you can claim a separately identifiable storage area used regularly for inventory or product samples. Daycare providers licensed (or exempt from licensing) under state law can claim space that doubles as personal living area outside business hours, using a time-and-space calculation on the form.⁴

Part I: Figuring Your Business Percentage

Part I produces the percentage that drives every calculation on the rest of the form. The most common method is square footage: measure the area used regularly and exclusively for business on Line 1, enter the total area of your home on Line 2, and divide.⁵ If your office is 200 square feet and your home is 2,000, your business percentage on Line 7 is 10%.

Any reasonable method that accurately reflects business use is acceptable, but square footage is what the form is built around. Keep a floor plan with measurements in your records. If the IRS questions the number later, that is what you will show them.

Daycare providers fill in additional lines to convert daycare hours to a percentage of the 8,760 hours in a year, then combine that time percentage with the space percentage.

Part II: Direct and Indirect Expenses

Part II is where you enter actual home expenses in two columns. Column (a) is for direct expenses that benefit only the business space, such as painting the office or replacing its flooring. These are fully deductible. Column (b) is for indirect expenses that benefit the entire home; the form multiplies these by the business percentage from Part I.⁵

Typical indirect expenses include:

Deductible mortgage interest on Line 10, pulled from your Form 1098.
Real estate taxes on Line 11.
Homeowner’s or renter’s insurance.
Rent, if you don’t own.
Utilities such as electricity, gas, water, and internet on Line 19.
Repairs and maintenance affecting the whole house.

Before you subtract anything, the form makes you enforce the gross income limitation. Your home office deduction generally cannot exceed the gross income from the business use of the home, so you first subtract your other business expenses (the ones already on Schedule C) from your gross business income to see how much room is left for home expenses.⁴

Expenses are then applied in a set order. Items you could deduct even without a business, mortgage interest and real estate taxes, come first. Operating expenses like utilities, insurance, and repairs come next. Depreciation comes last. If the income limit cuts off any of these, the leftover doesn’t vanish; it moves to Part IV as a carryover.

Part III: Depreciation of Your Home

If you own your home, Part III turns the building (not the land) into a depreciation deduction. On Line 37 you enter the smaller of your home’s adjusted basis or its fair market value at the time you first used it for business.⁶ Subtract the value of the land, apply your business percentage from Part I, and you have the depreciable basis of the business portion.

The IRS treats a home office as nonresidential real property depreciated straight-line over 39 years.⁴ The percentage you enter on Line 41 depends on when the home was first used for business. If that happened before 2025 (and after May 12, 1993), the rate is 2.564%. If it happened during 2025, the rate is based on the month the space was placed in service, from 2.461% for January down to 0.107% for December.⁵

Some people are tempted to skip depreciation to sidestep tax consequences when they sell. That backfires. When you sell a home you used for business, the IRS taxes depreciation that was “allowed or allowable,” meaning you’ll owe the recapture tax whether or not you actually claimed the deduction. Depreciation you were entitled to after May 6, 1997 is recaptured as unrecaptured Section 1250 gain, taxed at a maximum rate of 25%.⁷⁸ Skipping the deduction just means you pay more tax now and still owe recapture later.

Part IV: Carryover of Unallowed Expenses

If the gross income limitation stopped you from deducting everything this year, Part IV calculates what carries forward. Line 43 captures unallowed operating expenses. Line 44 captures unallowed excess casualty losses and depreciation.⁵

The IRS instructions set no time limit on how long the carryover can sit. It travels with you if you move to a different home. Carried expenses are subject to the deduction limit in the year you actually use them. If you switch to the simplified method in a later year, you can’t claim prior carryovers during that year, but they aren’t lost; they wait until you switch back to the regular method.⁹

Where the Total Goes and How to File

Line 36 is the allowable deduction. That number is entered on Line 30 of your Schedule C, where it reduces your net profit.¹ If you e-file with tax software, Form 8829 attaches automatically, and most filers get an acceptance confirmation within 24 hours.

Paper filers include Form 8829 with the Form 1040 and Schedule C, and mail to the service center listed on the IRS “Where to File” page for their state.¹⁰ Paper processing runs six weeks or more, compared with under three weeks for e-file.¹¹

Documentation to Keep With the Form

The numbers on Form 8829 need to be defensible. A few practical records to keep filed with the return:

A floor plan with measurements supporting the square footage on Lines 1 and 2.
Dated photos of the office space showing dedicated business use.
Form 1098 for mortgage interest, and property tax statements.
Utility bills, insurance declarations, and any repair or maintenance invoices.
Closing documents and any improvement records that establish your home’s adjusted basis for Part III.

The exclusive use test is the one that trips people up most often. A room that doubles as the guest bedroom or a laptop on the kitchen table doesn’t qualify, and claiming otherwise puts the whole deduction at risk.

When the Simplified Method Is a Better Choice Than Form 8829

Form 8829 isn’t the only path. The simplified method gives you $5 per square foot of home office space, capped at 300 square feet, for a maximum deduction of $1,500. No expense tracking, no depreciation, and no depreciation recapture when you sell.⁹ Under the simplified method, mortgage interest and property taxes stay entirely on Schedule A instead of being split.

You can switch methods from one year to the next, but once you pick a method for a given tax year you’re locked in for that year. If your actual home expenses substantially exceed $1,500, or you want the depreciation deduction, Form 8829 is where the larger number lives. If your office is small and your expenses are modest, the simplified method may deliver a similar result without the recordkeeping.

1
Internal Revenue Service. Instructions for Schedule C (Form 1040) (2025)
2
Ways and Means Committee. The One Big Beautiful Bill Section by Section
3
Office of the Law Revision Counsel. 26 U.S. Code 280A
4
Internal Revenue Service. Publication 587 (2025), Business Use of Your Home
5
Internal Revenue Service. Instructions for Form 8829
6
Internal Revenue Service. IRS Form 8829
7
Internal Revenue Service. Publication 523 (2025), Selling Your Home
8
Internal Revenue Service. Topic No. 409, Capital Gains and Losses
9
Internal Revenue Service. Simplified Option for Home Office Deduction
10
Internal Revenue Service. Where to File Addresses for Form 1040
11
Taxpayer Advocate Service. Lifecycle of a Tax Return