Guide · Personal Auto

How much auto coverage do you actually need?

Most guides answer this with a number pulled from your net worth, or a flat "100/300 is plenty." Both are built for the average household, and both quietly leave high-asset families in the wrong place. Here's how we size it for our clients.

Logan Kroloff

Licensed Insurance Agent

5 min read

The right auto limit isn't set by what the state requires or what your lender will accept. Those are floors built for the average driver, not a measure of what you could owe. The amount that matters is whatever it takes to keep a serious at-fault accident from reaching past your insurance and into your savings, your home equity, and your future income.

That makes the real input your assets and income, not the make of your car or the minimum on a registration form. A schoolteacher and a software founder who cause the same accident face the same damages; the difference is how much each has exposed if the policy limit gives way.

What you're protecting

The claim that reaches your assets.

Liability is the part of your auto policy that pays for the harm you cause to others. This includes their injuries, their lost income, their vehicle and property. It also pays to defend you. When a claim settles inside your limit, the policy absorbs it and you never feel it. When it doesn't, the balance is yours: paid from savings, investments, equity, or garnished from future earnings.

Most auto claims are modest. The average bodily-injury claim runs in the tens of thousands. The accidents that threaten a household are the rare severe ones: a multi-car collision, a permanently disabling injury, a wrongful-death claim involving a working-age earner. Those resolve in the hundreds of thousands, occasionally the millions. Sizing your limit is really about making sure the severe-but-survivable claim is within your limits.

The number we recommend

For most of our clients: $500K CSL.

For high-net-worth households, we generally recommend a $500,000 combined single limit on their auto policy. A combined single limit is a single pool of coverage for any one accident, available in any mix of bodily injury and property damage. That's the meaningful difference from a split limit like 250/500/100, which caps a single injured person at $250,000 no matter how severe their claim. Combined single limit removes that per-person ceiling.

$500K CSL does two things at once. It satisfies the underlying-limit requirement nearly every umbrella attaches above, and it's high enough to contain the large majority of serious accidents on its own. This keeps the umbrella in reserve for the rare catastrophe instead of being pulled into ordinary claims.

How the limits ladder up

Where the common limits leave you.

It helps to see the recommendation against other tiers.

25/50/10 — state minimum

Meets the law and little else. One serious injury blows through it, and the balance comes straight from your assets. Dangerously thin for any household with something to protect.

Floor of last resort

100/300/50 — the mass-market floor

Adequate for many ordinary households, and the point where an umbrella can first attach cleanly above it. Still light once real assets are in the picture.

Where an umbrella can first attach

250/500/100 — a reasonable step up

Fewer gaps, but still a split limit: a single catastrophic injury is capped at $250K per person. Better than the floor, short of where HNW households should sit.

Better, but still split

$500K CSL — where we put most HNW clients

A single $500K pool with no per-person cap, sitting beneath an umbrella. Covers the majority of accidents outright and meets standard umbrella attachment requirements.

Our default recommendation

$1M CSL or the carrier maximum — — the maximum

The right move when an umbrella isn't in place, or if you want the maximum possible coverage.

Exception, not the plan

Insurer and state availability varies.

Limit availability and CSL options vary by carrier and state. A large umbrella or certain carriers may require a $1M CSL floor underneath rather than $500K.

Why not just rely on the umbrella

Keep the umbrella in reserve.

If an umbrella sits above the auto policy anyway, why not run a thinner auto limit and let the umbrella catch everything above it? Because the umbrella works best as the layer you almost never touch. Pulling it into routine-serious claims means more frequent claims against it, more erosion of a limit meant for true catastrophe, and a messier two-policy claim every time the auto limit runs short.

A $500K CSL auto layer absorbs the accidents that are more likely to happen, leaving the umbrella to do the one job it's priced for: the rare, severe judgment that runs into the millions. And the cost of carrying the stronger underlying limit is modest. Moving up the auto ladder adds far less than people expect, because higher liability limits are among the cheapest coverage on the policy.

The one exception

When you don't carry an umbrella.

There's one situation where the math changes: no umbrella. Some households can't place one, and a few choose not to. If the auto policy is your only liability layer, it has to do all the work. In that case, carry the maximum auto limit available. This is typically $1M CSL. You lose the umbrella's reach, so you take as much coverage as the auto policy will give you.

This is the exception, not the plan. For most HNW households, $500K CSL plus a properly sized umbrella protects more, for less, than maxing the auto policy alone ever could.

Common questions

On auto limits, specifically.

A combined single limit is one pool of liability coverage for an accident, usable in any mix of injury and property damage. A split limit like 250/500/100 divides coverage into separate buckets and caps each. CSL removes that per-person ceiling, so a single severely injured claimant can draw the full limit. For the rare severe accident you're actually insuring against, that flexibility is the whole point.

For most households, yes. $500K CSL contains the large majority of serious claims on its own and meets the underlying-limit requirement most umbrellas attach above. The umbrella then sits in reserve for the rare judgment that runs past it. Very large umbrellas or certain carriers may require a $1M CSL floor instead — an advisor confirms which applies to you.

Yes. The umbrella only attaches above a qualifying underlying limit, and it pays best when it's rarely touched. A thin auto limit means the umbrella gets pulled into ordinary-serious claims, eroding a layer meant for catastrophe and complicating every claim. Strong auto limits underneath are what let the umbrella do its one job cleanly.

Less than most people expect. Liability limits are among the cheapest coverage on a policy, because the severe claims they guard against are rare. Moving up to $500K CSL usually costs far less than the protection it buys — which is exactly why under-limiting is the more common, and more expensive, mistake.

Then the auto policy carries the full load, so you max it out — typically $1M CSL or the highest limit your carrier writes — rather than settling at the $500K floor. It's the one case where loading up the auto limit is the right call instead of leaning on a layer above it.

The standard advice, such as match your net worth or carry 100/300, answers a different question for a different household. For families with significant assets, the cleaner frame is an auto policy that covers the accidents that are more likely happen, and an umbrella held in reserve. $500K CSL is where that floor usually sits.

Don't size to the minimum.
Size to the accident.

Carry enough on the auto policy to contain the serious-but-survivable claim. Then let your umbrella step for the rare catastrophe.

Get bespoke auto coverage.

Our insurance advisors will create a custom insurance program for your assets and exposures. Quotes typically come back within one business day.

Get a quote