The direct answer: federal corporate income tax is generally not deductible on Form 1120. Other taxes, such as employer payroll taxes, qualifying excise taxes and certain state, local or foreign taxes, may be deductible under their own rules.
This article separates deductions from payments, credits and book expenses. It covers the US Form 1120 only, so check the details against the IRS instructions for your tax year. Line references below follow the 2025 form.
Key Tax Takeaways
- Federal income tax paid or accrued by the corporation is not a deductible tax on Form 1120.
- Estimated payments reduce the balance owed. They are not expense deductions.
- Employer payroll taxes and some excise, state, local and foreign taxes follow separate rules.
- Taxes withheld from employees or collected from customers are not the corporation's own tax expense.
What Does Form 1120 Report?
What Form 1120 is used for
Form 1120 is the US federal income tax return for domestic corporations, including entities that elect to be taxed as corporations. It reports income, deductions, credits, taxable income and tax liability. Unless exempt or filing a special return, a domestic corporation files even with no taxable income.
A foreign corporation doing business in the US generally files Form 1120-F instead. Residence and domestic or foreign corporate status determine which return you file, not Australian ownership alone.
An Australian parent's US subsidiary incorporated in a US state is a domestic corporation and files Form 1120. An Australian company operating directly in the US may need Form 1120-F. Confirm which applies before using any rule below.
Where deductions and tax payments appear
On the 2025 form, the main locations are:
- Lines 12 to 26: deductions (line 17 is "Taxes and licenses")
- Line 27: total deductions
- Line 30: taxable income after special deductions
- Line 31: total tax, carried from Schedule J
- Line 33: total payments and credits
- Schedule J, line 14: current-year estimated payments
Payments sit in a different part of the return from deductions. They are applied against calculated tax, not treated as operating expenses.
Form 1120 versus Form 1120-S
Form 1120 is for C corporations, which pay tax at the entity level. Form 1120-S is for S corporations, where income and deductions pass through to shareholders on Schedule K-1. Don't apply K-1 box guidance to a C corporation's Form 1120. They are separate regimes.
Are Federal Taxes Deductible on Form 1120?
The short answer: generally not
IRC section 275 bars a deduction for federal income taxes. The Form 1120 instructions say the same for line 17: taxes and licenses exclude federal income taxes.
The rule attaches to the tax itself. It makes no difference whether the corporation paid through estimated instalments, a balance-due payment or an overpayment credit.
Why book tax expense differs from the return
Under US GAAP, ASC 740 requires an income tax provision in the financial statements. That is an accounting measure. Taxable income is a different calculation, and the federal income tax expense must be added back or excluded when preparing the return.
The difference shows up in the book-to-tax reconciliation:
- Schedule M-1, line 2: "Federal income tax per books"
- Schedule M-3, Part III: current and deferred US income tax expense
Corporations with year-end total assets of US$10 million or more generally file M-3 instead of M-1.
Payments are not deductions
Estimated payments are treated as payments on account of income tax under IRC 6315. They reduce the amount owed or increase a refund. They don't reduce taxable income.
A simple illustration:
- Start with revenue and subtract allowable deductions to reach taxable income.
- Apply the tax rate to get the tax liability.
- Subtract estimated payments and any prior-year overpayment credit.
- The result is the balance owed or the refund.
Federal income tax enters at step 3 only. It never appears in step 1.
Avoiding double tax benefits
The same foreign tax can't be both deducted and claimed as a credit. IRC 275(a)(4) bars the deduction when the section 901 credit is chosen. The Form 1118 instructions describe an annual election: if you claim the credit for a year, you generally can't deduct any of that year's foreign income taxes. Check current IRS guidance before choosing.
Which Taxes Can a Corporation Deduct?
The federal income tax exclusion is not a blanket ban on every federal tax. Other taxes may be deductible under IRC 162 (ordinary and necessary business expenses) and IRC 164 (taxes), each with its own limits.
Employer payroll and employment taxes
The employer's share of payroll taxes is generally deductible as a business expense. For 2026, the employer rates are:
| Tax | Employer rate | Wage base |
|---|---|---|
| Social Security | 6.2% | First US$184,500 per employee |
| Medicare | 1.45% | No limit |
Additional Medicare Tax has no employer share. Federal income tax withheld from wages, and the employee's own Social Security and Medicare, are different. Those are the employees' taxes, remitted on their behalf. They are not a second employer deduction.
Federal excise taxes and similar business taxes
Excise taxes connected to operations may be deductible, but the treatment depends on the tax. Where the cost relates to producing or buying goods, IRC 263A may require it to be capitalised into inventory instead.
Form 1120's line 17 instructions also exclude taxes connected with acquiring or disposing of property. Those amounts go into the asset's cost or reduce sale proceeds.
Taxes recovered from customers are a separate case. A tax is generally deductible only by the person on whom it is imposed.
State, local and foreign taxes
State and local taxes fall outside the federal income tax prohibition. IRC 164 allows deductions for:
- Real property taxes
- Personal property taxes
- State, local and foreign income taxes
- Taxes paid in carrying on a business
The individual SALT cap in IRC 164(b)(6) applies to individuals, not C corporations.
Foreign income taxes require a choice between deduction and foreign tax credit. An Australian group with US operations should coordinate US and Australian advice, since a tax treated one way in one country may interact with relief in the other.
Timing, capitalisation and refunds
A tax's treatment depends on how it arises:
- Paid or accrued: depends on the corporation's accounting method
- Capitalised: included in asset cost or inventory (IRC 263A)
- Refunded: a refund of a previously deducted tax is generally income to the extent the deduction reduced tax
A tax that isn't deductible now may still affect inventory cost, asset basis or cost of goods sold.
Which Taxes Are Not Deductible or Need Special Treatment?
Federal corporate income tax
Federal income tax appears on the income statement but is excluded from Form 1120 line 17 (Taxes and licenses). Do not claim it as a taxes-and-licenses deduction. Confirm the treatment in the Form 1120 instructions for the relevant tax year.
Employee withholding and customer-collected taxes
Withheld income tax, employee payroll withholdings and sales taxes collected from customers are generally liabilities until remitted. They aren't the corporation's own tax expense.
Watch for a common trap: recording these amounts as revenue or expense and again as a tax deduction. Keep the books consistent with the return.
Penalties, fines, interest and disputed liabilities
These are different items from the underlying tax and shouldn't be lumped together.
- Fines and penalties: IRC 162(f) generally disallows amounts paid to a government for legal violations, subject to narrow exceptions such as restitution and compliance payments.
- Interest: IRC 163(a) allows interest on indebtedness, and tax interest is separate from the tax and penalty. Section 163(j) may limit business interest to business interest income plus 30% of adjusted taxable income.
- Underlying tax: Section 162(f) doesn't override IRC 275. A federal income tax payment stays nondeductible.
Publication 535 was discontinued after its 2022 revision. Rely on the current statutes, regulations and instructions instead.
Credits, refunds and taxes claimed elsewhere
A credit, refund, carryover or prior-year adjustment is not a current-year deduction. Each may need separate reporting. Do not deduct a foreign tax you also claim as a credit, and do not deduct an amount already counted in another tax computation.
How to Report Deductible Taxes and Tax Payments on Form 1120
Prepare a tax classification checklist
Reconcile the general ledger and trial balance, and separate these items:
- Federal income tax expense
- Employer payroll taxes
- Employee withholdings
- Excise taxes
- State and local taxes
- Foreign taxes
- Estimated payments and refunds
- Penalties and interest
Keep invoices, payroll records, tax notices, payment confirmations, foreign tax documents and workpapers for each material item. The IRS expects records that substantiate every income and deduction figure on the return.
Connect the classification to the right location
Deductible taxes generally go in the deductions section, such as line 17. Estimated payments, credits, balances due and overpayments belong in the Schedule J and payments portion, feeding lines 31 to 37. The combined payments figure is line 33.
Supporting schedules may be needed:
- Form 1118 for the foreign tax credit (Schedule J, line 5a)
- Capitalisation or depreciation schedules
- Schedule M-1 or M-3 for the book-to-tax reconciliation
Common mistakes and when to get help
Typical errors include:
- Deducting federal income tax
- Treating estimated payments as expenses
- Deducting employee withholdings
- Overlooking capitalisation rules
- Claiming the same foreign tax twice
VJM Global works with Australian businesses and other international companies on accounting classification, US tax compliance coordination and financial documentation review. Its services include bookkeeping, financial statement preparation and corporate tax return preparation. A ledger review before filing often catches these errors.
Frequently Asked Questions
Is federal tax deductible on 1120?
Federal corporate income tax is generally not deductible on Form 1120. Certain other taxes may be deductible under separate rules.
What is line 16D on 1120S K-1?
That is Form 1120-S Schedule K-1, not Form 1120. In the 2025 shareholder instructions, Box 16 Code D means distributions that reduce stock basis; confirm against the current instructions.
Are estimated federal tax payments deductible as business expenses?
No. Estimated payments apply to tax due or a refund, but they don't reduce taxable income. They are recorded on Schedule J, line 14.
What taxes can a C corporation deduct on Form 1120?
Qualifying employer payroll taxes, certain excise or operating taxes, and potentially state, local or foreign taxes. Each has its own limits, capitalisation rules and timing requirements.
Does an Australian company use Form 1120 for its US business?
It depends on legal structure, tax election and US activities. A US-incorporated subsidiary files Form 1120. A foreign corporation with US activity may file Form 1120-F and may need a protective return even under a treaty.
Can a corporation deduct foreign income taxes instead of claiming a foreign tax credit?
Generally yes, as an annual choice, but the same tax can't receive both benefits. Check current IRS rules and get cross-border advice before electing.
