How is permanent disability calculated in California?

A physician’s whole-person impairment (WPI) is multiplied by 1.4 (for injuries on or after 1/1/2013 under SB 863) to get the standard rating, then adjusted for the worker’s occupation and age, reduced by any non-industrial apportionment (Lab. Code §4663), combined with other impairments via the Combined Values Chart, and finally converted to weeks and dollars under Lab. Code §§4658 and 4453.

What is the 1.4 modifier?

For dates of injury on or after January 1, 2013, SB 863 replaced the old FEC (future-earning-capacity) rank with a single flat multiplier: standard rating = round(WPI × 1.4). Injuries from 2005–2012 instead use an impairment-specific FEC rank.

Why isn’t 20% plus 20% equal to 40%?

Multiple impairments are combined with the Combined Values Chart, not added, so no one can be rated over 100%. The formula is a + b − (a×b)/100. So 20 and 20 combine to 36, and 15 and 25 combine to 36, not 40.

Does a higher occupational group always mean a higher rating?

No. The occupational variant can raise or lower the standard rating depending on how physically demanding the job is for that impairment. A heavy-labor group raises a back or knee rating; a sedentary group lowers it but can raise a psychiatric or hearing rating.

How California Permanent Disability Is Calculated

A step-by-step walkthrough of how a California workers’-comp permanent-disability rating is built — from whole-person impairment through the 1.4 modifier, occupation, age, apportionment, the Combined Values Chart, and the final PD% and dollars.

A California permanent-disability (PD) rating isn’t one number a doctor writes down — it’s built in a fixed sequence set by the 2005 Permanent Disability Rating Schedule (PDRS) and the Labor Code. This guide walks the whole path, from the physician’s impairment figure to the final percentage and the dollars it’s worth. You can run any of it yourself in the free calculator.

The rating, step by step

1. Start with whole-person impairment (WPI)

An AME or QME rates the injury under the AMA Guides, 5th edition, and reports a whole-person impairment percentage. Some body parts are reported on their own scale first and converted to WPI:

Upper extremity (UE) × 0.6 = WPI · Hand × 0.9 = UE
Lower extremity (LE) × 0.4 = WPI · Foot × 0.7 = LE

See how each body part converts for the region-by-region detail.

2. Apply the 1.4 modifier (or the FEC rank)

For injuries on or after January 1, 2013 (SB 863), the WPI is multiplied by a flat 1.4 to get the standard rating. For injuries from 2005 through 2012, an impairment-specific FEC rank is used instead.

Standard rating = round(WPI × 1.4) → e.g. 10% WPI × 1.4 = 14

3. Adjust for occupation

The worker’s job maps to one of 45 occupational groups. Each group assigns every impairment a variant (C–J) that raises or lowers the standard rating based on how much that injury affects that kind of work. A machinist’s back injury goes up; an accountant’s goes down. See how each occupation adjusts a rating.

4. Adjust for age

Older workers receive a modestly higher rating for the same impairment; younger workers, a lower one. The adjustment comes straight from the PDRS age table.

5. Subtract apportionment (Lab. Code §4663)

If part of the disability was caused by something non-industrial — prior injury, degenerative disease — that percentage is removed. An 80% industrial cause on a 20% rating leaves 16%.

6. Combine multiple impairments (Combined Values Chart)

When there’s more than one body part, the ratings are combined, not added, so the total can never exceed 100%. Ratings are combined largest-first, rounding at each step.

Combined(a, b) = round(a + b − a × b ÷ 100) → 25 C 15 = 36 (not 40)

7. Convert to weeks and dollars

The final PD% becomes a number of weeks (Lab. Code §4658) paid at a weekly rate that is two-thirds of average weekly earnings, clamped to statutory caps for the year of injury (Lab. Code §4453). See the exact rate caps by year and what a rating is worth. Ratings of 70–99% add a lifetime life pension; 100% is permanent total disability.

Worked example · DOI 2024

A warehouse claim with a lumbar spine, right-shoulder, and cervical impairment combines to 32% PD. At the 2024 rate cap that is 145.00 weeks × $290 = $42,050 of PD indemnity. Walk the full breakdown on the sample exhibit, or rate your own in the calculator.

Reading the result

The calculator (and the DEU) express the whole computation as a single rating string — for the lumbar spine in the example above, 100% (15.03.01.00 - 8 - [1.4]11 - 230E - 10 - 11) = 11% PD. Each segment is one of the steps above. We break the format down field by field in how to read a PD rating string.