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Accounting and state tax in Iowa

Iowa taxes corporations at 5.5% on the first $100,000 and 7.1% above for 2026, apportions by a single sales factor, and follows the federal code on a rolling basis.

Jurisdiction
Iowa
Reading time
3 min
Checked
October 13, 2026
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Key figures

Iowa accounting

2026, with sources

Corporate rate, first $100,000
5.5%Tax years beginning in 2026; unchanged from 2025.
Corporate rate, above $100,000
7.1%Falls only when net corporate receipts pass $700 million in a fiscal year.
Starting point and conformity
RollingFederal taxable income from tax years beginning 2023; the IRC as amended, except where Iowa law says otherwise.
Apportionment
Single sales factorThrough the Business Activity Ratio on the IA 1120.
Return due
April 30Calendar-year corporations; an automatic six-month extension applies when 90% of the tax is paid on time.
Estimated payments required
Over $1,000 of tax after creditsFour installments on Form IA 1120ES.

Two corporate rates, ratcheting down

Iowa taxes corporations at 5.5% on the first $100,000 of Iowa taxable income and 7.1% above it for tax years beginning in 2026. The rate is set each year by an order of the Department of Revenue: when net corporate income tax receipts in the prior fiscal year exceed $700 million, the top rate is recalculated downward, until it reaches 5.5% on all income. Fiscal 2025 receipts were about $621.2 million, so Order 2025-02 kept 2026 at the rates that applied in 2024 and 2025. The top rate was 8.4% as recently as 2023.

For a startup the practical rate is 5.5%: a company with less than $100,000 of Iowa-apportioned income never reaches the second bracket. A deferred tax computation for a company that expects to stay small can use 5.5%; one that expects large Iowa income should model the blended rate.

Federal starting point, rolling conformity

Since tax years beginning in 2023, Iowa computes taxable income from federal taxable income, and it follows the Internal Revenue Code as amended rather than as of a fixed date. Federal changes therefore reach the Iowa return unless Iowa law says otherwise. Bonus depreciation is allowed for assets placed in service in tax years beginning on or after January 1, 2021, and Section 179 limits match federal from 2020; the IA 4562A and IA 4562B carry the adjustments for older assets, and the IA 163 carries the business interest adjustment.

The return is due on the last day of the fourth month after year end. Iowa grants an automatic six-month extension to file when at least 90% of the correct tax has been paid by the original due date; the extension does not extend the time to pay. Estimated payments are due in four installments, on the last day of the fourth, sixth, ninth and twelfth months, once tax after credits is more than $1,000.

Single sales factor

Iowa apportions C corporation business income with a single sales factor, the Business Activity Ratio. Receipts from services are reported on their own line and sourced under Iowa Administrative Code rule 701—503.6. A SaaS company with one employee in Des Moines and 2% of its revenue from Iowa customers apportions about 2% of its income to Iowa.

Iowa’s franchise tax applies only to financial institutions, so an ordinary C-corp pays the income tax and nothing on capital.

Deadlines

  1. Last day of the 4th month after year end (Apr 30)Corporation income tax returnIA 1120
  2. Last day of the 4th, 6th, 9th and 12th months of the tax yearEstimated tax installments, when tax due after credits is more than $1,000IA 1120ES
  3. Oct 31 for calendar-year corporationsAutomatic six-month extension to file, if 90% of the tax is paid by the original due date

The federal baseline

This page covers what Iowa adds. The federal rules underneath it apply here too.

FederalFederal accounting for startupsFederal law sets the tax rules, not the bookkeeping ones: US GAAP comes from the FASB and from what investors expect, while Form 1120, the cash-method test and Section 174 come from the IRS. Every state builds its corporate tax on this return.

Common questions

Is Iowa’s corporate rate a flat 5.5% now?

Not yet. Iowa law cuts the top corporate rate only when net corporate income tax receipts exceed $700 million in the prior fiscal year. Fiscal 2025 receipts were about $621.2 million, so the Department’s order kept 2026 at 5.5% on the first $100,000 and 7.1% above it. The ratchet continues until every dollar is taxed at 5.5%.

Does Iowa follow federal tax changes automatically?

Mostly. Iowa follows the Internal Revenue Code as it changes (rolling conformity), and since tax years beginning in 2023 it starts from federal taxable income. The Department’s examples of differences are depreciation on certain assets placed in service before 2021, certain Section 179 elections and the business interest expense limitation, each with its own adjustment, so the Iowa figure is not always the federal one.

Accounting next door

How Iowa compares

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More of the Iowa guide

Sources

Checked against each agency’s own page on . Rates and thresholds change, usually on January 1.

General information for US companies, not tax, legal or accounting advice for yours. Rules and thresholds change; confirm the specifics with a CPA or the agency before you act on them.

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