The spine is the most-rated body part in California workers’ comp, and “what’s my back worth” is the question every party asks first. The honest answer is a computation, not a quote: whole-person impairment × the schedule’s adjustments × the statutory dollars. This page runs that computation across the whole realistic range, with every figure produced by the rating engine.
How back injuries are measured
Physicians rate the lumbar spine under the AMA Guides’ DRE method (impairment number 15.03.01.00), which sorts injuries into categories with fixed WPI anchors: category II (5–8% — muscle guarding, asymmetric motion loss), category III (10–13% — verifiable radiculopathy), category IV (20–23% — fusion or lost motion-segment integrity), and category V (25–28% — both). The category call is the physician’s; everything after the WPI is arithmetic, and that arithmetic is what moves the money.
The money table
Final PD and total indemnity for the common DRE anchor WPIs, computed for three occupations at age 42–46, 2026 injury, maximum PD rate ($290/week), single impairment, before apportionment:
| WPI | Clerical · 111 | Custodian · 340 | Carpenter · 380 |
|---|---|---|---|
| 5% (cat. II floor) | 5% · $4,350 | 9% · $7,830 | 11% · $9,932.50 |
| 8% (cat. II top) | 8% · $6,960 | 14% · $13,412.50 | 15% · $14,645 |
| 10% (cat. III floor) | 11% · $9,932.50 | 17% · $17,545 | 19% · $20,445 |
| 13% (cat. III top) | 14% · $13,412.50 | 21% · $23,345 | 23% · $26,245 |
| 20% (cat. IV floor) | 22% · $24,795 | 33% · $44,080 | 36% · $50,170 |
| 25% (cat. V floor) | 29% · $36,177.50 | 40% · $58,290 | 43% · $64,380 |
Read down a column and the WPI drives the dollars; read across a row and the occupational variant does — the same spine is worth roughly twice as much on a construction site as at a desk, because the schedule rates lost earning capacity, not anatomy. Every percentage maps to weeks and dollars on the PD money chart.
Same WPI, different jobs — the strings
Here is the 13% WPI row as the DEU would write it, for the clerk and the carpenter:
Same impairment, same ×1.4, same age — the variant letter (C vs. H) is the entire difference. Paste either string into the rating-string decoder and it verifies every step against the schedule.
Apportionment: the number that shrinks
Spine cases attract apportionment like no other body part — degenerative disc disease is nearly universal on imaging past 40, and Labor Code §4663 requires the physician to split industrial from non-industrial causation. The split applies at the end of the string:
The unapportioned rating was 36% PD — $50,170. The 30% non-industrial finding removed $20,952.50. That single physician’s sentence is worth more than most disputes over the WPI itself, which is why how apportionment works — and whether the report’s split is substantial evidence — is where back cases are actually fought.
What this table can’t tell you
The PD indemnity is the computable anchor, not the whole case: multiple body parts combine on the CVC rather than add, temporary disability and future medical ride on top, and a settlement prices the medical tail and litigation risk beyond any table. And if your rate is below the maximum — most workers’ is not — the dollars scale down with your average weekly wage. Companion pages: the knee and shoulder versions of this analysis. Estimates for informational use; not legal or medical advice.