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How To File Form 8829 for Expenses for Business Use of Your Home


If you have a home-based business or you are using your home for business purposes, you may deduct expenses for business use of your home. This article will take you through the process of filing IRS Form 8829-Expenses for Business Use of Your Home.

Note that this article is presented for general information purposes. Your particular situation may be more complex or different from the situation discussed here. Be sure to consult a tax professional for assistance with completing this form and claiming this deduction.

Difficulty: Average
Time Required: One hour or more, depending on complexity of situation

Here's How:

  1. Part of Your Home Used for Business
    Part I calculates the percentage of your home used for business. This section asks you to describe the part of your home that is used for business. If you have a home-based business, you must set aside an area of your home that is REGULARLY and EXCLUSIVELY for business use. (This does not apply for day care businesses.)

  2. For the calculation, you will need to determine the square feet of the area used for the business and divide that by the total square feet of your home, for a percentage used. For example, if your home business area is 200 square feet, and the total area of your home is 2000 square feet, your home business takes up 10 percent of the total home area.

  3. If you have a day care business, you also need to determine the percentage of time the area is used for day care over a year. For example, if you use the day care area six hours a day, five days a week, for 50 weeks a year, you would be using the area for day care 1560 hours a year. Out of 8760 hours a year (365 days x 24 hours), you are using the area 17.8 percent of the total time available.

  4. Allowable Deduction Calculation
    To calculate the allowable deduction, in Part II:
    First enter the tentative profit from Line 29 of Schedule C. Then enter direct expenses and indirect expenses for:
    Casualty Losses
    Deductible Mortgage Interest, and
    Real Estate Taxes
    And Multiply by the percent of your home devoted to your business (line 7). Then, you can deduct
    Excess Mortgage Interest
    Insurance costs
    Repairs and maintenance
    Other expenses
    (Home office phone expenses are different and a little more complicated)
    All of these deductions, added up, get you to a total allowable operating expenses.

  5. Other Deductions
    The next part is complicated (you will need a tax adviser), as it has to do with deductions carried over from the previous year and excess casualty losses and
    depreciation (see step 6).
    The total deduction for business home expenses is entered on Line 35.
  6. Part III - Depreciation of Your Home
    This section is used to calculate the depreciation on your home, so it can be allocated to your home business according to the percentage on Line 7. A tax adviser can help you with this section. The total amount of depreciation is entered on Line 29 above (see Step 5).
  7. Part IV - Carryover of Unallowed Expenses
    Some unallowed expenses may be able to be carried over to 2009. Again, you will need the help of a tax adviser to figure this one out.


  1. As you can see, this form is complicated. You can help minimize the time (and expense) of having a tax preparer work on this form. Here are some ways you can prepare:
  2. Measure the square footage of the area used for your home business. Be sure there is nothing in that area that is not related to your business, except for decorations. Take several photos of the area from different angles, so it is clear that the area is used "exclusively" for business. Time/date the photo and keep a copy of it in a safe place.
  3. Also calculate the total square footage of your home. If you have a realtor's listing from when you purchased the home, or if there is a legal document with the square footage, that will help to verify the number. If you can't find any other measurements, get a good measuring tape and walk around taking measurements of each room. Don't include bathrooms, the garage, or the basement (unless it's furnished). Keep the measurements in a safe place or in your tax file.
  4. Collect information on expenses for your home for the year, including property tax payments, mortgage interest statements, utility bills, homeowners insurance, rent payments, repairs and maintenance expenses.
  5. Distinguish direct expenses from indirect ones. Direct expenses are those directly related to your home business. For example, if you have your home business inventory in the garage and the roof leaked, you would need to repair the roof to protect your merchandise. That is a direct expense.

    Back to Taxes and Your Home Business

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