Louisiana Corporate Tax Calculator (C-Corp State Tax)

Louisiana taxes corporate income at a flat 5.50% rate (not a graduated bracket schedule), applying uniformly to all C-corporation income apportioned to the state. That figure is identical to the rates levied by Florida and Iowa, two states with which Louisiana otherwise shares little in common economically.

Because there is a single statutory rate, the marginal and effective rates are identical at every income level: a small Louisiana-based contractor and a national retailer with a Louisiana distribution footprint both face the same 5.50% rate once their income is apportioned to the state. That places Louisiana modestly below the national middle among states that tax corporate income, below neighboring Alabama's 6.50%, though still well above Arkansas's graduated schedule, which reaches its 4.30% top bracket at just $25,000 of apportioned income.

On the calculator's $500,000 baseline, that flat structure produces $27,500.00 in Louisiana tax, identical to Florida's and Iowa's totals on the same income, and notably less than the $32,500.00 the same base would generate under a 6.50%-rate state like Alabama.

Louisiana replaced its graduated corporate schedule with a single 5.50% rate and repealed the corporate franchise tax that used to run alongside it, which makes the 2026 Louisiana computation far simpler than any Louisiana worksheet more than a year or two old. The old three-bracket schedule and the franchise tax on capital employed in the state are both gone.

1. Read the income field as the taxable base. The single income input is taken as Louisiana taxable corporate income exactly as typed. The code applies no modification, allocation or deduction to it before the rate stage; it is the base.
2. Apply the single statutory rate. Louisiana's 5.50% rate is multiplied against that figure with no bracket lookup, because the schedule has one band running from the first dollar: $500,000 x 5.50% = $27,500.00.
3. Subtract credits and floor the result at zero. The credits field is subtracted from the step-2 figure and the difference is clamped at $0.00, so no credit entry can drive the liability negative. With the field at its $0 default the $27,500.00 stands; enter $11,000 of credits and the page returns $16,500.00, a reduction of exactly the credit entered because the subtraction is a straight one.
4. Derive the reported rates from those two numbers. The effective rate is the tax divided by the income entered, 5.50% here, and the top statutory bracket is reported separately as 5.50%. Net after-tax retained profit is the income less the tax, $472,500.00. Those four outputs are the whole of what the engine produces.

Using this calculator's baseline scenario: a corporation with $500,000 in taxable income apportioned to Louisiana.

1. Start with apportioned taxable income. The corporation has already apportioned $500,000 of its total taxable income to Louisiana using the state's statutory apportionment formula, before any state-level tax is applied.
2. Apply Louisiana's flat statutory rate. Louisiana taxes all C-corporation income at a single flat rate of 5.50%, regardless of income size, so no bracket lookup is required: $500,000 × 5.50% = $27,500.00.
3. Louisiana corporate tax due: $27,500.00.
4. Net retained profit. Subtracting the state tax liability from taxable income leaves $500,000 − $27,500.00 = $472,500.00 in after-tax profit retained by the corporation, before any separate federal tax liability is applied.

Because Louisiana uses a single flat rate rather than graduated brackets, the 5.50% effective rate is identical to the marginal rate at every income level: a corporation earning $50,000 and one earning $50 million both face the same 5.50% state rate on their apportioned income.

The table under the calculator runs apportioned income from $83,333.33 to $1,000,000.00 in twelve steps. Louisiana tax runs $4,583.33 to $55,000.00, and passes $27,500.00 at the $500,000 baseline. Every row is exactly 5.50% of its income, so the effective-rate column never moves.

There is no threshold in this schedule. Louisiana taxes corporate income at one rate from the first dollar, so the sweep contains no step, and the answer to "what happens if we book one more dollar of Louisiana income" is 5.5 cents at every income level in the table and outside it. A filer who is used to graduated states will look for a kink in the chart and there is not one.

Marginal cost of the next unit. Each additional $1,000 of apportioned income costs $55.00; the baseline moves from $27,500.00 to $27,555.00. Each additional $1,000,000 costs $55,000.00.

The reverse question. With a constant rate the inverse is a division: a $27,500 Louisiana tax bill corresponds to $500,000 of apportioned income, and a $55,000 bill to $1,000,000, which the sweep's final row confirms at $55,000.00. The question worth more to a multistate filer is the comparison at the margin: the same $500,000 produces $32,500.00 in a 6.50% state such as Alabama, so each dollar sourced to Louisiana rather than Alabama saves one cent of state corporate tax, $5,000.00 across this base.

The error that costs the most, priced. The input is income already apportioned to Louisiana. The engine applies no apportionment formula, no throwback rule and no combination of unitary affiliates; it multiplies the figure you type by 0.055. A company with $2,000,000 of total taxable income and a quarter of its sales factor in Louisiana should enter $500,000 and owes $27,500.00. Entering the $2,000,000 total returns $110,000.00, overstating the bill by $82,500.00.

What the twelve rows never reflect. Credits go into the headline calculation and not into the schedule. compute subtracts the credit field from the final figure but builds each table row from the raw bracket walk, so the table always shows Louisiana tax before credits, and the two will disagree whenever the credit field is non-zero.

• Federal Taxable Income Starting Point. Net corporate earnings are determined under IRC § 63 before Louisiana modifications. This calculator starts one step later: the income box is read as the finished Louisiana taxable figure and nothing is derived from a federal return.
• Louisiana Additions & Subtractions. Louisiana adjustments are applied, including the state's treatment of federal depreciation and its handling of interest and intangible expenses. No addback and no subtraction is computed anywhere in this page's code path, so enter an income figure that already reflects them.
• Apportionment Factor Allocation. Louisiana apportions general business income on a single sales factor, with separate statutory formulas for certain regulated industries. The engine performs no apportionment of any kind. The word does not appear in the primitive this page binds to; the figure you type is taken as the Louisiana figure and multiplied by the rate as it stands.
• Net Operating Loss (NOL) Deductions. Allowable Louisiana NOL carryforwards reduce the base, subject to the state's limitation on the percentage of income a carryforward may offset. No loss deduction is applied by this calculator. If a carryforward is available, subtract it yourself before entering the income.
• Franchise Tax Confirmation. No corporate franchise tax is added. Louisiana repealed it, so a computation that still includes one is working from a superseded rule. It is not added to the figure this page returns.
• Federal corporate income tax (21% under IRC § 11).
• Specialized gross receipts taxes (e.g. Ohio CAT, Washington B&O, Texas Franchise Tax) where applicable.
• Minimum entity franchise tax fees or annual report filing charges.
• Base Erosion and Anti-Abuse Tax (BEAT) or Global Intangible Low-Taxed Income (GILTI) provisions.
• Local municipal corporate earnings taxes (e.g. NYC General Corporation Tax).

• Mistaking the Flat Rate for the Final Bill: Assuming Louisiana's 5.50% rate applies directly to book income rather than to apportioned taxable income after state additions, subtractions, and NOL adjustments.
• Improper Apportionment Sourcing: Applying market-based sourcing vs cost-of-performance rules incorrectly for service revenue apportioned to Louisiana.
• Ignoring Unitary Group Combined Reporting: Failing to account for Louisiana's mandatory combined return requirements across related entities.
• Neglecting State NOL Carryforward Caps: Overlooking Louisiana's annual percentage limitations on net operating loss deductions, which matter more once the 5.50% rate is applied to a larger taxable base.

• Louisiana Department of Revenue: Corporate Tax Statutes and Guidance (2026). revenue.louisiana.gov
• Multistate Tax Commission (MTC): Uniform Apportionment and Allocation Guidelines. mtc.gov