Workers comp research guide
SIBTF calculator for California subsequent injuries benefits
Estimate a California SIBTF award from the combined rating, the 4751 gateway, and the 4753 credit, then verify the official rules before you rely on it.
Subsequent injuries fund
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Estimate the SIBTF gap
Enter the combined permanent disability rating, the rating for the subsequent injury alone, and your weekly permanent disability rate. The estimator applies the section 4658(e) week table and the section 4751 thresholds.
Arithmetic only. Both ratings have to rest on medical evidence in existence before the subsequent injury, and multiple body parts are combined with the Combined Values Chart rather than added.
Estimated fund indemnity
$90,553
Meets the section 4751 threshold on these numbers
Combined PD weeks
513.25
Later injury PD weeks
201
Combined PD value
$148,843
Later injury PD value
$58,290
Section 4753 credit
$0
Life pension
$116 a week for life
The life pension uses Labor Code section 4659(a): 1.5% of average weekly earnings, capped at $515.38, for each point above 60, paid for life after the permanent disability weeks run out and increased most January 1s to track the state average weekly wage.
This is an educational estimate. State rules, caps, medical evidence, attorney fees, and future care can change the result.
The Subsequent Injuries Benefits Trust Fund (SIBTF) is a California special fund, not your employer or its carrier. It pays additional compensation when a worker who was already permanently partially disabled is injured again and the combined permanent disability is 70% or more, provided one of the Labor Code section 4751 gateways is met. The award is the compensation for the combined disability minus the compensation payable for the subsequent injury alone, reduced by money you already received for the preexisting disability under section 4753. SIBTF is claimed separately, by application to the Workers' Compensation Appeals Board, and the fund pays only after a final determination of liability.
This page is educational information, not legal advice, and it does not create an attorney-client relationship. SIBTF eligibility and the amount of an award turn on medical evidence, apportionment, procedural deadlines, and the law that governs your claim. Talk to a qualified California workers' compensation attorney about your own case.
Illustrative SIBTF week gap by combined rating
Cumulative week counts from the Labor Code section 4658(e) bands for dates of injury on or after January 1, 2013: each band's weeks are added to the bands below it, so 70% is 433.25 weeks, not 70 x 16. The gap column assumes the subsequent injury alone is rated 35% (166 weeks), the smallest rating that opens the section 4751 gateway without an opposite-member finding. Multiply any week gap by your own weekly permanent disability rate to see dollars.
SIBTF questions
- What is the SIBTF?
- The Subsequent Injuries Benefits Trust Fund is a California state fund that pays additional permanent disability compensation to workers who were already permanently partially disabled before a work injury. It exists so employers can hire workers with a prior disability without carrying the full cost of the combined disability.
- Who qualifies for SIBTF benefits?
- Under Labor Code section 4751(a), the combined permanent disability must be 70% or more, and one of two gateways must be met: the preexisting disability affected a hand, arm, foot, leg, or eye and the subsequent injury is to the opposite corresponding member at 5% or more whole person impairment after apportionment, or the subsequent injury alone is 35% or more after apportionment. A 100% permanent total disability caused by the industrial injury alone is a bar under section 4751(b).
- How is a SIBTF benefit calculated?
- Section 4751(a) pays the compensation for the remainder of the combined permanent disability that exists after the last injury: the value of the combined disability minus the compensation payable for the subsequent injury alone. Section 4753 then reduces the award by money you already received for the preexisting disability, apart from listed exceptions such as military pensions and certain public assistance. Because the combined rating can be 70% or more while the employer owes nothing above 70%, the fund often also owes the life pension the carrier never owed.
- Does the preexisting disability have to be work-related?
- No. It can come from a car accident, an illness, a congenital condition, or an earlier injury, work-related or not. What matters is that it was labor disabling when the subsequent injury happened. Section 4750(e) defines labor disabling, and section 4754.1(b) requires evidence that existed before the subsequent injury, so a work restriction written after the fact will not establish it.
- How and when do I apply for SIBTF?
- SIBTF is a separate defendant and a separate application, filed with the Workers' Compensation Appeals Board; the SIBTF Claims Unit pays only after the board makes a final determination of liability. Under section 4754.2 an application must be filed within five years of the subsequent injury or six months after the permanent disability issue in that claim is resolved, whichever is later. SB 171 (2026) also keeps the prior version of the statute for certain pending claims that met procedural milestones by June 1, 2026.
Before you rely on a SIBTF estimate
- Get both ratings in writing: the combined permanent disability and the rating for the subsequent injury alone, after apportionment.
- Confirm which section 4751 gateway applies and whether SB 171's June 1, 2026 procedural rules or the older statute govern the claim.
- List every payment you already received for the preexisting disability, because section 4753 reduces the fund award by those amounts.