What this line means
The sum of all business expenses from lines 8 through 27a. This is the total cost of running your business before the home office deduction is applied. Tax software calculates this automatically. If you file on paper, add lines 8 through 27a carefully — math errors here affect everything below.
Does this apply to you?
- Every Schedule C filer completes this line — it is a calculated total
- Tax software fills this in automatically
- Paper filers add all expense lines manually
Easy to overlook
Review every expense line before accepting this total Line 28 is only as good as the individual expense lines feeding into it. Before moving on, scan lines 8 through 27a and ask yourself: did I capture advertising, car expenses, supplies, software subscriptions, professional fees, insurance, and every other legitimate business cost? Most sole proprietors understate their expenses because they miss recurring small charges. 1 General filing pattern — missed deductions reducing total expenses
This total does not include the home office deduction The business use of home deduction (line 30) is applied separately after this total. Your true total deductions are line 28 plus line 30. This matters when comparing your expenses to your income for profitability analysis. 2 IRS Schedule C instructions — Line 28
Watch out for this
Making an arithmetic error when adding lines 8-27a on a paper return. With 20+ lines to add, simple math mistakes are common and delay processing. The IRS will correct the math, but the correction generates a notice and delays your refund. E-filing eliminates this problem.
Footnotes
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IRS Schedule C (Form 1040) Instructions. See also IRS Publication 17, Your Federal Income Tax. https://www.irs.gov/pub/irs-pdf/p17.pdf ↩
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IRS Schedule C (Form 1040) Instructions, Line 28. https://www.irs.gov/instructions/i1040sc ↩