U.S. · Tax forms
Schedule C line 18, office expense.
What the IRS puts here, and how it differs from supplies, depreciation and other expenses.
Line 18 (“Office expense”) is for your expenses for office supplies and postage, in the words of the IRS instructions. Materials and supplies consumed in the business go on line 22, depreciable equipment on line 13, and anything the form has no line for goes in Part V and line 27b.
Look up an expense line
Result
Office expense next to the nearby Schedule C lines
| Item | Meaning | What the IRS says |
|---|---|---|
| Line 18 | Office expense | Office supplies and postage |
| Line 22 | Supplies (not included in Part III) | Cost of materials and supplies actually consumed and used in the business in the year |
| Line 13 | Depreciation and section 179 expense deduction | Items whose usefulness extends substantially beyond a year are generally recovered through depreciation |
| Line 38 | Materials and supplies (Part III, cost of goods sold) | Supplies counted in cost of goods sold are not repeated on line 22 (the line 22 label says “not included in Part III”) |
| Lines 27b and 48 | Other expenses | Business expenses the form has no specific line for are listed in Part V; the total on line 48 is entered on line 27b |
| Line 28 | Total expenses before home office | Add lines 8 through 27b |
What the instructions actually say
The Schedule C instructions for line 18 are one sentence: include on this line your expenses for office supplies and postage. They do not list further examples, so for anything that is not plainly an office supply or postage, compare it to the neighbouring lines and, if still unsure, ask a tax preparer how that item is classified.
Office supplies versus line 22
Line 22 covers the cost of materials and supplies you actually consumed and used in the business during the tax year, and the instructions add that books, professional instruments, equipment, etc. can be deducted if you normally use them within a year. If their usefulness extends substantially beyond a year you must generally recover the cost through depreciation (line 13).
Where the total lands
Line 18 is added into line 28 with the other Part II expenses. Line 28 is subtracted from gross income on line 7 to get the tentative profit or loss on line 29.
Worked example
Sam, a freelance bookkeeper, bought $85 of printer paper and pens and spent $42 on stamps and mailing envelopes in 2025. Both are office supplies and postage, so line 18 shows $127. A $900 standing desk that will last for years is not a line 18 item; it is generally a depreciation question for line 13. Names and figures are made up.
More line pages in this set
Related lines: Schedule C Line 22, Schedule C Line 13, Schedule C Line 29.
Sources
- Instructions for Schedule C (Form 1040) (2025): the line-by-line instructions on this page. Page last reviewed or updated April 30, 2026. Read November 2, 2026.
- Schedule C (Form 1040): the printed line wording and arithmetic on the form. Read November 2, 2026.
Tax year 2025 instructions (page last reviewed or updated April 30, 2026). The line labels were read from the Schedule C (Form 1040) PDF the IRS had posted on the date read, which is marked 2026; line numbers can shift between years, so check them against the form for your tax year. Names in worked examples are made up.
Frequently asked questions
What is office expense on Schedule C?
Per the IRS instructions for line 18, your expenses for office supplies and postage.
What is the difference between line 18 and line 22?
Line 18 is office supplies and postage. Line 22 is materials and supplies you consumed and used in the business, and items like books or equipment that you normally use up within a year.
Where does a long-lasting purchase go?
If its usefulness extends substantially beyond a year, the instructions say you must generally recover its cost through depreciation, shown on line 13.
Where do expenses without their own line go?
In Part V (Other Expenses). The total on line 48 is entered on line 27b.
Does line 18 include home office costs?
No. The Part II heading says to enter expenses for business use of your home only 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.