- Who files M-1, who files M-3, and who files neither
- The left side: adding back
- The right side: taking away
- Line 5c: the travel and entertainment list
- Line 7 and the Schedule K link
- How M-1 differs from M-3
- Common reasons the reconciliation won't balance
- Filling it in, step by step
- The verdict
- Frequently asked questions
Schedule M-1 is the part of Form 1120 where a corporation reconciles its net income or loss per its own books with the income it reports for tax. It starts from book profit, adds items taxed but not booked and expenses booked but not deductible, then subtracts the reverse, ending at the taxable income figure on page 1, line 28. Corporations with total assets of $10 million or more file Schedule M-3 instead, and the smallest can skip it.
Everything below comes from the IRS's 2025 Form 1120 and its instructions, as of October 2026.
Who files M-1, who files M-3, and who files neither
| Corporation | What it completes |
|---|---|
| Total receipts and total assets at year end both under $250,000, with Yes checked on Schedule K, question 13 | No Schedule M-1, M-2 or Schedule L |
| Total assets under $10 million | Schedule M-1, or Schedule M-3 voluntarily |
| Total assets of $10 million or more on the last day of the tax year | Schedule M-3 instead of M-1 |
| Required to file M-3 but with total assets under $50 million | Either all of M-3, or M-3 Part I plus Schedule M-1 in place of M-3 Parts II and III |
That last row is the shortcut mid-sized corporations often miss. If you take it, Schedule M-1, line 1 has to equal Schedule M-3, Part I, line 11.
The left side: adding back
| Line | What goes there |
|---|---|
| 1 | Net income (loss) per books |
| 2 | Federal income tax per books, because it isn't deductible |
| 3 | Excess of capital losses over capital gains |
| 4 | Income subject to tax but not recorded on the books this year |
| 5 | Expenses recorded on the books but not deducted on the return: (a) depreciation, (b) charitable contributions, (c) travel and entertainment |
| 6 | Add lines 1 through 5 |
The right side: taking away
| Line | What goes there |
|---|---|
| 7 | Income recorded on the books this year but not included on the return, such as tax-exempt interest |
| 8 | Deductions on the return not charged against book income this year: (a) depreciation, (b) charitable contributions |
| 9 | Add lines 7 and 8 |
| 10 | Income (page 1, line 28): line 6 less line 9 |
If line 10 doesn't match page 1, line 28 of Form 1120, something on the return or in the books is missing, and that's the whole point of the schedule.
Line 5c: the travel and entertainment list
Line 5c is where many small corporations lose track, because book expenses include costs the tax rules don't allow. The instructions list what belongs there:
- entertainment expenses not deductible under section 274(a), and expenses for an entertainment facility
- meal expenses not deductible under section 274(n)
- qualified transportation fringes not deductible under section 274(a)(4)
- the part of business gifts over $25
- an individual's convention expenses on cruise ships over $2,000
- employee achievement awards over $400, or $1,600 if part of a qualified plan
- the cost of skyboxes, nondeductible club dues and luxury water travel not deductible under section 274(m)
- travel as a form of education, and other nondeductible travel and entertainment
Line 7 and the Schedule K link
Tax-exempt interest received or accrued goes on line 7, including exempt-interest dividends from a mutual fund. The instructions say to report the same amount on Schedule K, item 9, so the two have to agree.
How M-1 differs from M-3
Schedule M-1 is a ten-line summary. Schedule M-3 asks for the source of the financial statements and splits every difference into temporary and permanent amounts across three parts. That's why only corporations at $10 million or more in assets are forced onto M-3, and why the under-$50 million option to use M-1 for Parts II and III saves real time.
Common reasons the reconciliation won't balance
Most M-1 problems come from a handful of items that are booked one way and taxed another. Depreciation is the classic example, which is why it appears on both sides of the schedule: line 5a for book depreciation above the tax figure, and line 8a for tax depreciation above the book figure. Charitable contributions work the same way on lines 5b and 8b. Federal income tax booked as an expense always comes back on line 2, and a capital loss larger than your capital gains always goes on line 3, because the corporation can't deduct it this year.
If line 10 still won't match page 1, line 28, check for income taxed this year but booked in another, such as items on line 4, before assuming there's an error in the books.
Filling it in, step by step
- Start from the profit or loss in your accounting records for the year, not the tax figure.
- Add back federal income tax booked as an expense, and any capital losses above capital gains.
- List income the return taxes but your books don't show yet.
- Itemize book expenses you can't deduct, using line 5c for travel and entertainment.
- Subtract book income the return doesn't tax and deductions not yet in your books.
- Check that line 10 equals page 1, line 28.
The verdict
Schedule M-1 is a reconciliation, not extra tax, and it's quicker than it looks once your books are closed. The two places to slow down are line 5c, where non-deductible meals and entertainment hide, and depreciation, which often differs between your books and the return. Get line 10 to match page 1 and the schedule has done its job.
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Some corporations also have to list their owners on a separate schedule, which is covered in the voting stock ownership schedule.
Frequently asked questions
What is Schedule M-1?
It's the Form 1120 schedule that reconciles a corporation's net income or loss per books with its income per return.
Who doesn't have to complete Schedule M-1?
Corporations with total receipts and total assets at year end under $250,000 that check Yes on Schedule K, question 13.
When must a corporation file Schedule M-3 instead of M-1?
When its total assets are $10 million or more on the last day of the tax year.
Can a corporation required to file M-3 still use Schedule M-1?
Yes, if its total assets are under $50 million: it can complete M-3 Part I and Schedule M-1 instead of M-3 Parts II and III.
What goes on Schedule M-1 line 5c?
Travel and entertainment expenses recorded on the books but not deductible, such as nondeductible meals and entertainment, club dues and business gifts over $25.
What should Schedule M-1 line 10 equal?
It should equal taxable income on Form 1120, page 1, line 28.
