The General Business Credit: How Credits Combine and Carry
Why business tax credits are added together before they are applied, the limit that caps them, the order they are used in, and the carryback and carryforward that keep unused credit alive.
Reviewed by the Fairlight Accounting cross-border tax team — U.S. & Canadian Tax Desks
Most business tax credits — research, work opportunity, retirement plan startup, disabled access, and dozens more — are combined into a single general business credit on Form 3800 before being applied. The combined credit is limited to the tax on the return above a floor; any excess generally carries back one year and forward 20 years, used oldest first.
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What is the limit?
| Step | Calculation |
|---|---|
| 1 | Net income tax (regular tax plus alternative minimum tax, minus nonrefundable personal credits and certain other credits such as the foreign tax credit) |
| 2 | Subtract the greater of the tentative minimum tax, or 25 percent of net regular tax above $25,000 |
| 3 | The result is the maximum general business credit for the year |
In practice, the credit can offset the first $25,000 of net regular tax, but 25 percent of any excess stays payable, and for individual owners the credit generally cannot reduce tax below the tentative minimum tax — except for "specified credits," such as the research credit of an eligible small business (average annual gross receipts of $50 million or less over the prior three years), the work opportunity credit, and the Section 48 energy credit, which are figured treating tentative minimum tax as zero. For a C corporation, the floor is 25 percent of net income tax above $25,000.
How does the ordering work?
Credits are used in a fixed order within the year — carryforwards first (oldest year first), then the current year's credits, then carrybacks — and within each group in the order the code lists them. Because unused credit carries forward 20 years, the order rarely costs a business credit permanently, but it decides which credits expire first.
How do carrybacks and carryforwards work?
Unused credit is first carried back one year, generating a refund of tax paid that year, then forward for 20 years. Clean-energy credits eligible for elective payment (the "applicable credits" of Section 6417(b)) carry back three years instead. The carryback is claimed on an amended return or Form 1139 (corporations) or Form 1045 (individuals). Certain credits that remain unused at the end of the carryforward period (the "qualified business credits" of Section 196) are deductible in the following year.
What about pass-through owners?
Credits generated by a partnership or S corporation pass to the owners on Schedule K-1 and are applied on the owners' returns, subject to the owners' own limits. Credits from passive activities are further limited to the tax on passive income. An owner with no tax liability in the year — because of other losses — carries the credit back or forward personally.
Which credits are outside the general business credit?
The research credit amount a qualified small business elects to apply against payroll taxes (it is removed from the income tax credit and its carryforward), payroll tax credits such as the employee retention credit (now closed), and personal credits such as the child tax credit. These follow their own rules.
Frequently asked questions
Can a credit create a refund?
Not directly; the credit reduces tax down to the limit and the rest carries. Refunds come only from carrybacks (which reduce a prior year's tax), refundable credits, or — for tax-exempt entities and a few clean-energy credits — the Section 6417 elective payment election.
Does the credit reduce self-employment tax?
No. It applies against income tax only.
What happens to credits when the business is sold?
Credit carryforwards belong to the taxpayer that generated them — the owner for pass-throughs, the corporation for C corporations — and corporate carryforwards are limited after an ownership change.
Do I file Form 3800 every year?
Yes, in any year you claim a general business credit — current-year, carryforward, or carryback — together with the source form for each credit.
Official sources
The IRS explains: “In general, unused general business credits may be carried back 1 year and carried forward 20 years.” — Internal Revenue Service, Instructions for Form 3800 and Schedule A (2025), https://www.irs.gov/instructions/i3800
The Internal Revenue Code provides: “The credit allowed under subsection (a) for any taxable year shall not exceed the excess (if any) of the taxpayer’s net income tax over the greater of— (A) the tentative minimum tax for the taxable year, or (B) 25 percent of so much of the taxpayer’s net regular tax liability as exceeds $25,000.” — Legal Information Institute, Cornell Law School, 26 U.S. Code § 38 - General business credit, https://www.law.cornell.edu/uscode/text/26/38
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