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Split Limits vs Combined Single Limit (CSL) Explained

Split limits (like 100/300) cap each person and the whole crash separately. A combined single limit uses one pool. How they differ in a multi-injury accident—education only.

Alex Rivera3 min read
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Educational only. PolicyPlain does not sell insurance and does not provide insurance, legal, or financial advice. Coverage rules and prices vary by state and insurer. Read our full disclaimer.

Auto quotes often show 100/300 or a single number like $300,000 CSL. Those are different ways to write liability caps. Same marketing word—“liability”—different math when more than one person is hurt.

Educational only—not advice to buy a specific limit.

Split limits in one glance

A common US bodily injury split looks like 100/300:

NumberUsual meaning
First (100)Up to $100,000 for one injured person
Second (300)Up to $300,000 for all injured people in that crash

Property damage (PD) is often a third number. See 50/100 vs 100/300 and property damage liability.

Combined single limit (CSL)

A combined single limit is one pool—for example $300,000 CSL—that the insurer can apply to covered liability damages for that accident under the policy’s rules. There is no separate “per person” BI cap in the classic split sense.

Some CSL forms wrap BI only; others combine BI and PD in one number. Always read the declarations page—do not assume every “CSL” means the same thing.

Where the difference shows up

One severely injured person

  • Split 100/300: that person is capped at $100,000 even if $200,000 of the per-accident pool is unused.
  • $300,000 CSL: more of the pool can go to that one person (subject to policy wording).

Several injured people

  • Split 100/300: the $300,000 per-accident cap matters; no one person can take more than $100,000.
  • CSL: claimants share one pool; allocation follows policy and claim practice—not a free-for-all.

Watch how split caps drain across claimants:

Interactive tool

Liability waterfall

Accident limit remaining$0 left

  • Driver A injuries

    Claimed

    $75,000

    Policy pays

    $50,000

    Uncovered (you)

    $25,000

  • Passenger injuries

    Claimed

    $45,000

    Policy pays

    $45,000

    Uncovered (you)

    $0

  • Property / other

    Claimed

    $18,000

    Policy pays

    $5,000

    Uncovered (you)

    $13,000

Hard truth from this scenario

$38,000 uncovered

Policy pays $100,000 of $138,000 claimed. Per-person caps and the per-accident bucket both bite—this is why “state minimum” is not a risk plan.

Claimed dollars: paid vs uncovered

  • Policy pays$100,000
  • Uncovered (you)$38,000

Driver

Paid $50,000

Passenger

Paid $45,000

Property

Paid $5,000

Decision pack · Download a colorful Excel workbook with your numbers, checklist, and matched guides—built for this run, not a blank template.

Full page: Liability waterfall simulator

Fair quote comparison

  1. Ask whether Quote A is split BI and Quote B is CSL
  2. Confirm whether CSL includes PD or BI only
  3. Run the same two scenarios: one catastrophic injury; three moderate injuries
  4. Align UM/UIM, deductibles, and other lines before comparing price

Decision checklist

  1. Circle BI (and PD) on each declarations page or quote
  2. Label each quote “split” or “CSL”
  3. Ask for a written example with two claimants
  4. Only then decide if the premium gap is worth it

Sources

Disclaimer

PolicyPlain publishes educational explainers and tools. Forms and laws vary. This is not a quote or legal advice.

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Frequently asked questions

What are split limits?+

Split bodily injury limits use two numbers—per person and per accident—such as 100/300. Each injured person has a personal cap, and all injured people together share the per-accident cap.

What is a combined single limit (CSL)?+

A CSL is one dollar amount that can pay for bodily injury (and sometimes property damage, depending on how the policy is written) for a covered accident, instead of separate per-person and per-accident BI caps.

Is CSL always better than 100/300?+

Not automatically. A large CSL can be more flexible when one person is severely hurt; a high split can be stronger when many people are hurt. Compare equal total protection and price—not labels.

Can I compare a split-limit quote to a CSL quote?+

Only after translating both into the same crash story. Ask the agent to walk through two injured people and one severe injury under each form, then compare premium.

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