California vs Illinois Income Tax — 2026
A single filer earning $100,000 pays $250 less per year in Illinois than in California — $21 a month. California charges $5,055; Illinois charges $4,805.
Why this pair has a page: two of the largest taxing states.
California: tax year 2025 figures. The California amounts shown here are the 2025 brackets, standard deduction and exemptions, published for 2026 because California has not yet published its 2026 inflation-indexed brackets, standard deduction or exemption credits. The 2026 Form 540-ES instructions confirm the structure for 2026 — nine brackets from 1% to 12.3% plus the 1% Behavioral Health Services Tax above $1,000,000 — and direct taxpayers to the 2025 standard deduction and exemption credit amounts in the meantime. Source: California Franchise Tax Board, 2025 California Tax Rate Schedules (Form 540 booklet), verified .
The bill at every income
Single filer, standard deduction, no dependents. State income tax only.
| Gross income | California tax | Illinois tax | Difference |
|---|---|---|---|
| $50,000 | $1,040 | $2,330 | $1,291 less in CA |
| $75,000 | $2,775 | $3,568 | $793 less in CA |
| $100,000 | $5,055 | $4,805 | $250 less in IL |
| $150,000 | $9,705 | $7,280 | $2,425 less in IL |
| $250,000 | $19,005 | $12,230 | $6,775 less in IL |
| $500,000 | $43,968 | $24,605 | $19,363 less in IL |
| $1,000,000 | $102,982 | $49,355 | $53,627 less in IL |
California: tax year 2025 figures. The California amounts shown here are the 2025 brackets, standard deduction and exemptions, published for 2026 because California has not yet published its 2026 inflation-indexed brackets, standard deduction or exemption credits. The 2026 Form 540-ES instructions confirm the structure for 2026 — nine brackets from 1% to 12.3% plus the 1% Behavioral Health Services Tax above $1,000,000 — and direct taxpayers to the 2025 standard deduction and exemption credit amounts in the meantime. Source: California Franchise Tax Board, 2025 California Tax Rate Schedules (Form 540 booklet), verified .
California: tax year 2025 figures. The California amounts shown here are the 2025 brackets, standard deduction and exemptions, published for 2026 because California has not yet published its 2026 inflation-indexed brackets, standard deduction or exemption credits. The 2026 Form 540-ES instructions confirm the structure for 2026 — nine brackets from 1% to 12.3% plus the 1% Behavioral Health Services Tax above $1,000,000 — and direct taxpayers to the 2025 standard deduction and exemption credit amounts in the meantime. Source: California Franchise Tax Board, 2025 California Tax Rate Schedules (Form 540 booklet), verified .
How the two systems differ
| California | Illinois | |
|---|---|---|
| Tax structure | Graduated | Flat rate |
| Top marginal rate | 13.3% | 4.95% |
| Number of brackets | 9 | 1 |
| Standard deduction (single) | $5,706 | None |
| Personal exemption | $153 credit | $2,925 |
| Local income taxes | No | No |
| Capital gains | ordinary | ordinary |
| Population (2024) | 39,431,263 | 12,710,158 |
California: tax year 2025 figures. The California amounts shown here are the 2025 brackets, standard deduction and exemptions, published for 2026 because California has not yet published its 2026 inflation-indexed brackets, standard deduction or exemption credits. The 2026 Form 540-ES instructions confirm the structure for 2026 — nine brackets from 1% to 12.3% plus the 1% Behavioral Health Services Tax above $1,000,000 — and direct taxpayers to the 2025 standard deduction and exemption credit amounts in the meantime. Source: California Franchise Tax Board, 2025 California Tax Rate Schedules (Form 540 booklet), verified .
By filing status
| Filing status | California | Illinois | Difference |
|---|---|---|---|
| Single | $5,055 | $4,805 | $250 less in IL |
| Married filing jointly | $2,079 | $4,660 | $2,581 less in CA |
| Married filing separately | $5,055 | $4,805 | $250 less in IL |
| Head of household | $2,631 | $4,805 | $2,174 less in CA |
California: tax year 2025 figures. The California amounts shown here are the 2025 brackets, standard deduction and exemptions, published for 2026 because California has not yet published its 2026 inflation-indexed brackets, standard deduction or exemption credits. The 2026 Form 540-ES instructions confirm the structure for 2026 — nine brackets from 1% to 12.3% plus the 1% Behavioral Health Services Tax above $1,000,000 — and direct taxpayers to the 2025 standard deduction and exemption credit amounts in the meantime. Source: California Franchise Tax Board, 2025 California Tax Rate Schedules (Form 540 booklet), verified .
Change the assumptions
Adjust income and filing status, or swap either state. The URL updates so you can share the exact comparison.
At $100,000 as a single filer, Illinois costs $250 less per year than California — $21 a month.
| California2025 brackets | Illinois | Difference | |
|---|---|---|---|
| State income tax | $5,055 | $4,805 | $250 |
| Per month | $421 | $400 | $21 |
| Effective rate | 5.05% | 4.81% | 0.25 pts |
| Marginal rate | 9.3% | 4.95% | 4.35 pts |
| Standard deduction | $5,706 | $0 | $5,706 |
| Taxable income | $94,294 | $97,075 | $2,781 |
| Tax structure | Graduated | Flat rate | |
| Local income taxes | No | No |
California: tax year 2025 figures. The California amounts shown here are the 2025 brackets, standard deduction and exemptions, published for 2026 because California has not yet published its 2026 inflation-indexed brackets, standard deduction or exemption credits. The 2026 Form 540-ES instructions confirm the structure for 2026 — nine brackets from 1% to 12.3% plus the 1% Behavioral Health Services Tax above $1,000,000 — and direct taxpayers to the 2025 standard deduction and exemption credit amounts in the meantime. Source: California Franchise Tax Board, 2025 California Tax Rate Schedules (Form 540 booklet), verified .
Full detail: California · Illinois · methodology
What this comparison leaves out
Sources for both states
- 1.California Franchise Tax BoardState revenue department2026 Instructions for Form 540-ES, Estimated Tax for IndividualsRetrieved
- 2.Tax FoundationResearch organisation (cross-check)State Individual Income Tax Rates and Brackets, 2026Retrieved
- 3.Illinois Department of RevenueState revenue departmentFY 2026-15, What's New for Illinois Income TaxesRetrieved · "The personal exemption amount for tax year 2026 will increase to $2,925." Also states the $500,000 / $250,000 AGI cut-off.
Figures on this page were last checked against these sources on . Found something wrong? Report it.