California Income Tax Calculator

How 2025 California Form 540 income tax works

Form 540 starts on line 13 with your federal AGI from Form 1040 line 11b. Schedule CA (540) takes out tax-free state items on line 14 and adds state items on line 16. That gives your state AGI on line 17. U.S. Social Security and equivalent tier 1 railroad benefits come out on Schedule CA, Part I, Section A, line 6, column B, while tier 2 railroad benefits come out on line 5a and 5b, column B.

Line 18 takes the larger of your state itemized deductions or the 2025 standard deduction. The standard amount is $5,706 for Single or Married/RDP filing separately. It is $11,412 for joint filers, Head of Household, or a qualifying surviving spouse/RDP. Line 19 taxable income is line 17 minus line 18, down to $0.

Line 31 finds the tax two ways. Up to $100,000 of line 19 income, you must use the 2025 Tax Table. The table prices $1–$50 at $25 and $99,951–$100,000 at $99,975. Each $100 row from $51–$150 to $99,851–$99,950 uses its midpoint. Above that limit, you use Schedule X, Y, or Z shown in the next section.

Lines 7 to 10 give credits, not deductions, for exemptions. Each personal, blind, or senior box is worth $153. Joint and surviving-spouse returns get two personal boxes. Each dependent is worth $475. Above $252,203 of line 13 AGI ($378,310 Head of Household, $504,411 joint), each box loses $6 per $2,500 ($1,250 separate) of extra AGI, rounded up.

Line 33 takes line 32 credits off line 31 tax, down to $0. Above $1,000,000 of line 19 income, line 62 adds a 1% surtax on the excess. Starting in 2025, the state renamed the Mental Health Services Tax to the Behavioral Health Services Tax. It lifts the top rate from 12.3% to 13.3%.

Form 540 tax, exemption credit, and surtax formulas

California AGI (line 17) = round(federal AGI − Social Security + net other Schedule CA adjustments)
deduction (line 18) = $5,706 (Single/MFS) or $11,412 (MFJ/HoH/QSS) if standard, else round(itemizedDeductions)
taxable income (line 19) = max($0, California AGI − deduction)
Tax Table midpoint m = $25 (1..50), 100 × ceil((taxable − 50) ÷ 100) (51..99,950), or $99,975 (99,951..100,000)
taxBeforeCredits (line 31) = round(scheduleTax(m)) if taxable ≤ $100,000 else round(base + rate × (taxable − floor))
steps d = max(0, ceil((round(federal AGI) − limit) ÷ step)), where limit = $252,203 (Single/MFS), $378,310 (HoH), $504,411 (MFJ/QSS) and step = $1,250 (MFS) or $2,500
exemptionCredits (line 32) = max($0, $153 × boxes − $6 × d × boxes) + max($0, $475 × dependents − $6 × d × dependents)
taxAfterCredits (line 33) = max($0, taxBeforeCredits − exemptionCredits)
bhst (line 62) = round(0.01 × max($0, taxable income − $1,000,000)); totalTax = taxAfterCredits + bhst

Worked 2025 Form 540 examples

Default Single Tax Table row: The row from $89,251 to $89,350 uses the $89,300 midpoint. Tax is $3,201.97 plus 9.3% of $16,576, which is $4,743.54. That rounds to $4,744 on line 31 before the credit shown in the intro.

FTB booklet example (joint return, $136,412 AGI, $125,000 taxable): Schedule Y takes $125,000 minus the $115,084 floor, which is $9,916. Tax is 8% of that ($793.28) plus the base tax, or $4,768.10. That rounds to $4,768 on line 31, and two credits ($306) leave $4,462.

High earner with 1% surtax (Single, $1,205,706 AGI, $1,200,000 taxable): Schedule X adds 12.3% of $457,047 to the top base for $128,436.62 ($128,437 on line 31). Credits phase out to $0. Line 62 adds 1% of $200,000 ($2,000) for $130,437 total.

Scope, limits, and assumptions

• All 2025 brackets, standard deductions, credits, and AGI caps come from the FTB 2025 Form 540 Booklet and 2025 rate schedules.
• Applies to full-year residents on Form 540 who cannot be claimed by someone else. A dependent filer uses the $1,350 floor worksheet and gets 0 personal credits on line 7.
• Part-year filers and nonresidents use Form 540NR. It scales tax and credits by their state share of income. Form 540NR is not modeled here.
• Other credits on the Credit Chart (renter's, child care, CalEITC, Young Child, Foster Youth, and other-state tax credits) are not modeled. Schedule P 7% AMT and FTB 3800 or 3803 child taxes are not modeled either.
• Other changes on Schedule CA go into the net box as one number. Itemized amounts are used as typed without the Part II high-AGI cut.
• For tax years starting on or after January 1, 2025, California law generally conforms to the Internal Revenue Code as of January 1, 2025, with continuing differences in the 2025 Schedule CA instructions and FTB Publication 1001. It does not adopt the federal One Big Beautiful Bill Act (OBBBA) of July 4, 2025.

These figures are estimates for learning and planning, not financial, tax, legal or investment advice. Terms of use.

What to do with your California tax estimate

Subtract taxed Social Security on Schedule CA (540), Part I, Section A, line 6, column B (Form 540 Booklet, page 60). On $95,000 of Single AGI with $20,000 of benefits, that line drops state AGI to $75,000. It cuts the tax from $4,591 to $2,775, saving $1,816.

Claim every personal, senior, blind, and dependent box on lines 7 to 10. Each dependent is a $475 credit, so two kids cut a $95,000 Single filer's tax from $4,591 to $3,641.

Check state itemizing even if you take the IRS standard deduction. The state standard deduction is only $5,706 Single ($11,412 joint). At $200,000 Single AGI, $40,000 of itemized deductions cuts tax from $14,355 to $11,166.

Compare your Form 540 bill with your pay stubs and quarterly payments. Use the take-home pay tool and the quarterly tax tool to avoid penalties.

California income tax questions