U.S. · Tax forms
Form 8829 line 8, the income limit.
Schedule C line 29, plus gain from the home, minus losses unrelated to it.
Line 8 is your business-income ceiling for the home-office deduction: the amount from Schedule C, line 29, plus any gain derived from the business use of your home, minus any loss from the trade or business not derived from the business use of your home. If some income comes from elsewhere, you must first work out how much comes from the home.
Look up a line 8 piece
Result
Building line 8 (2025 form and instructions)
| Item | Meaning | What the IRS says |
|---|---|---|
| Start | Schedule C, line 29 | Tentative profit or (loss) from the Schedule C for this business |
| Add | Gain from business use of the home | Gain shown on Form 8949 (and included on Schedule D) or Form 4797 |
| Subtract | Losses not tied to the home use | Losses on Form 8949 (and Schedule D) or Form 4797 allocable to the business but not to the business use of the home |
| All income from the home | Use the formula directly | If all the gross income from your trade or business is from business use of your home |
| Income from other places too | Determine home share first | Consider time spent at each location and other facts; use Schedule C line 7 and gains from Form 8949, Schedule D and Form 4797 |
| Then subtract | Schedule C line 28 and losses | Subtract Schedule C total expenses (line 28) plus the allocable losses from the home-derived gross income; enter the result on line 8 |
| More than one Form 8829 | Only the period you owned that home | Include only income and deductions for the period you owned the home covered by Part I |
Why the limit exists
The later lines compare your allowable expenses to line 8: line 15 is line 8 minus line 14 (floored at zero), line 27 is the smaller of line 15 or line 26, and line 33 is the smaller of line 28 or line 32. These comparisons keep the allowable deduction within the business income measured on line 8; amounts that do not fit carry over on Part IV.
Columns (a) and (b) come next
Direct expenses benefit only the business part of the home; indirect expenses keep up the entire home and are multiplied by the business percentage on line 7. Expenses that are not allocable to business use of the home, such as salaries, supplies and advertising, are deductible elsewhere on Schedule C and do not belong on Form 8829.
Order of operations
Because line 8 starts from Schedule C line 29 (before home-office expenses), you complete the rest of Schedule C Part II first, then Form 8829, then enter Form 8829 line 36 on Schedule C line 30.
Worked example
Noah has Schedule C line 29 of $30,000. His business shows no gains or losses on Form 8949 or Form 4797, and all his gross income comes from work done at home. Line 8 is $30,000. If instead he earned part of the income at a client site, he would first determine the part of gross income from the home, then subtract the line 28 expenses, and enter that result. Names and figures are made up.
More line pages in this set
Related lines: Schedule C Line 29, Schedule C Line 30, Form 8829 Line 22.
Sources
- Instructions for Form 8829 (2025): the line-by-line instructions on this page. Page last reviewed or updated April 30, 2026. Read November 2, 2026.
- Form 8829 (2025): the printed line wording and arithmetic on the form. Read November 2, 2026.
Tax year 2025 edition of Form 8829 and its instructions (page last reviewed or updated April 30, 2026). Line numbers and dollar limits are those printed in the 2025 form and instructions and can change by year. Names in worked examples are made up.
Frequently asked questions
What goes on Form 8829 line 8?
The amount from Schedule C line 29, plus any gain derived from the business use of your home, minus any loss from the trade or business not derived from the business use of your home.
What if I earn money away from home too?
You first determine the part of your gross income from the business use of your home, considering time spent at each location and other facts, then subtract Schedule C line 28 expenses plus allocable losses and enter the result.
Where does the number go next?
Line 15 subtracts line 14 from line 8; the later limits compare your expenses to the result.
What if I have more than one home?
Use a separate Form 8829 for each home. Include only the income and deductions for the period you owned the home Part I describes.
Does line 8 use Schedule C line 31?
No. It uses line 29, which is figured before the home-office deduction on line 30.
Not tax advice
This page summarizes IRS instructions, mostly written for the people who prepare the form, and is not tax, legal or financial advice. A CPA or an enrolled agent can confirm what a line means for your return. Everything runs in your browser; nothing you enter is sent anywhere.