What Is SDI on My California Paycheck? (CASDI Explained + Real Examples)

If you work in California, you’ve probably seen a line on your pay stub called SDI, CASDI, or something similar and wondered: “What is this, and why am I paying it?”

Here’s the straight answer: SDI is California’s State Disability Insurance payroll deduction. It’s a separate deduction from California income tax, and it’s calculated as a simple percentage of your wages.

SDI in plain English (what it is and why it’s on your pay stub)

SDI = State Disability Insurance. It helps fund state-run benefits when you can’t work because of a qualifying disability, pregnancy, or to bond with a new child (Paid Family Leave). Your paycheck deduction is your “buy-in” to that coverage.

Most payroll providers label it as CASDI (California SDI). Some employers use a Voluntary Plan (VP) instead of the state plan, and your pay stub may show VPDI or another VP-related label.

If you’re also trying to understand the rest of your California paycheck (state income tax, local differences, deductions), run your numbers in our California paycheck calculator and compare it to a no-income-tax state like Texas to see what’s state-specific.

The 2026 SDI rate: 1.3% of wages (no wage cap)

California’s Employment Development Department (EDD) sets the SDI rate each year. For 2026, the official SDI withholding rate is 1.3% — and California applies it to all wages (there is no taxable wage ceiling).

How to calculate SDI on your paycheck (30-second check)

The fastest way to check SDI is to use the per-paycheck gross pay on your stub:

• Expected SDI ≈ (gross wages this paycheck) × 0.013

Example: if your gross pay this period is $2,400, SDI should be about $31.20. If your stub shows $31.18 or $31.22, that’s normal rounding.

Why your SDI amount changed (the 5 most common reasons)

People notice SDI when it spikes or drops. In most cases, it’s not “mystery tax” — it’s just math.

1) Your gross pay changed

SDI is a percentage of wages. Overtime, shift differentials, commissions, and bonuses all change your gross — so SDI changes too. If your gross pay went up 10%, SDI will also go up about 10%.

2) You had unpaid time (or a different number of hours)

If you took unpaid time off, started mid-pay period, or had fewer hours, your gross wages are lower — so SDI is lower.

3) You got a bonus paycheck

Many companies run bonuses as separate checks. SDI may be taken out of that check too, because it’s still wages. That’s why a “bonus stub” can show a surprising SDI line.

4) Your employer uses a Voluntary Plan (VP)

Some employers replace state SDI with an approved private plan. You might see VPDI (or another label) instead of CASDI, or you might see a different amount than expected.

5) You changed work location (multi-state or remote)

SDI is tied to California payroll rules. If you moved out of state, travel for work, or are fully remote, the “right” deduction depends on where your work is localized. Ask payroll which state they’re treating as your work location and why.

SDI vs. other California pay stub lines (PIT, UI, FICA)

California pay stubs are crowded. Here’s how SDI fits in:

• SDI / CASDI: disability/Paid Family Leave payroll deduction (percentage of wages)
• CA PIT / CA SIT (state income tax): California income tax withholding (depends on your DE 4 / W-4-style settings and your pay level)
• Social Security + Medicare (FICA): federal payroll taxes (nationwide rules)
• UI / ETT: usually employer-paid payroll taxes (typically not withheld from your paycheck as an employee)

If you’re trying to understand the full picture, SDI is just one piece. A full take-home estimate needs federal withholding, California PIT, FICA, and your benefits (health insurance, 401(k), etc.). That’s exactly what the California calculator is for.

How to put this to work (3 quick steps)

1) Do the 30-second SDI check. Take this paycheck’s gross wages and multiply by 0.013. Your SDI/CASDI line should be very close.

2) If it’s off, ask one clean question. “Is this employee on California SDI (CASDI) or a Voluntary Plan (VP) — and what wage types does your system include for SDI?”

3) Use your paycheck calculator to see the full take-home. SDI is only one line. Run your numbers in California and compare to Texas if you want a quick ‘high-tax vs no-income-tax’ gut check.