Personal injury cost per case is your total marketing spend for a period divided by the number of retainers signed from that marketing in the same period. It's the number that tells you whether a channel is working, because cost per click and cost per lead in PI swing too much to judge on their own. The hard part isn't the division. It's counting honestly, and setting a target that respects how much PI case values vary.
- Cost per signed case = all marketing costs for the channel ÷ signed retainers from that channel.
- Small changes in contact rate or sign rate move the result more than CPC does.
- Judge channels on a rolling 6–12 month window, because PI case values are lumpy.
- Set your target from your own fee history, not from an industry average someone quoted at a conference.
How to Calculate Personal Injury Cost per Case
To calculate personal injury cost per case, add every cost tied to a marketing channel for the period and divide by the retainers that channel produced. "Every cost" means more than ad spend:
- Media spend (Google Ads, Local Services Ads, purchased leads, sponsorships)
- Agency or management fees
- Call tracking, intake software and answering service costs tied to that channel
- Website or landing page costs, spread over a reasonable life
"Signed" should mean a signed fee agreement, not a "likely" case or a consultation booked. And decide in advance how you'll treat cases that are signed and later dropped (for example, because treatment records don't support the claim). Many firms report both: cost per signed case and cost per case still active after 90 days.
A Hypothetical PI Funnel, Step by Step
Here's an illustrative Google Ads month for a small firm in a competitive metro. The numbers are hypothetical, chosen to show the mechanics. Your own will differ.
| Stage | Hypothetical figure | What drives it |
|---|---|---|
| Ad spend | $12,000 | Budget, bids, competition |
| Average cost per click | $150 | Market, keywords, ad quality |
| Clicks | 80 | Spend ÷ CPC |
| Calls and forms (15% of clicks) | 12 | Landing page, mobile experience, hours |
| Qualified (50% of contacts) | 6 | Keywords, negatives, geography |
| Signed (50% of qualified) | 3 | Intake speed and skill |
| Cost per signed case | $4,000 | All of the above |
Now change one thing. If intake improves and signs four of the six qualified callers instead of three, cost per signed case falls to $3,000 without spending a dollar more on ads. If the landing page converts 20% of clicks instead of 15%, you get 16 contacts, 8 qualified and 4 signed at the same spend. Those levers are usually cheaper to pull than lowering CPC in an auction against TV advertisers.
The Same Math With Pay-Per-Lead
When you pay per lead, cost per lead is fixed, but cost per case still depends entirely on how many leads you sign. APM prices PI leads in the $200–$350 range; using a hypothetical $275 lead:
| Sign rate (hypothetical) | Leads per signed case | Cost per signed case |
|---|---|---|
| 10% | 10 | $2,750 |
| 20% | 5 | $1,375 |
| 30% | about 3.3 | about $917 |
Same lead price, a threefold spread in cost per case. That's why we tell every firm the same thing before they buy leads from anyone, including us: fix intake first. Our PI intake guide covers how, and buying personal injury leads compares vendor types.
Why Case Value Variance Changes Everything
PI is the one practice area where two signed cases from the same campaign can differ in value by a factor of a hundred. A soft-tissue claim against a minimum-limits policy and a catastrophic injury claim against a commercial carrier both count as "one signed case."
That has three consequences for budgeting:
- Short windows lie. A month or a quarter can look terrible or brilliant by chance. Judge channels over six to twelve months.
- Cost per case alone isn't enough. A channel with a higher cost per case can still be better if it brings in more serious injuries. Tag signed cases by type and severity tier so you can compare quality, not just count.
- Fees arrive late. You pay for marketing today and may collect the fee a year or more later. Your marketing budget has to be funded from current cash flow, not from projected settlements.
A PI marketing plan can look profitable on paper and still strain a small firm, because case costs (records, experts, filing fees) also come out before any fee comes in. Build your budget so the firm can survive a slow stretch without cutting marketing at the worst moment. Our law firm marketing budget guide covers the general approach.
Do you know what a signed PI case costs your firm?
We'll reconcile your ad spend and lead data with your signed retainers and show you cost per case by channel. If you've never calculated it, this is the place to start.
Setting a Target You Can Defend
Work backward from your own history. Pull the attorney's fees your firm actually collected on cases from a given channel or case type over the last couple of years, and find a typical fee (the median is often more honest than the average, since one large case distorts the average).
Then decide what share of that fee you're willing to spend acquiring the case. As a hypothetical: if your typical fee on motor vehicle cases is $9,000 and you'll spend up to 20% on acquisition, your target cost per signed case is $1,800. A new firm without history should start conservative and revise after a year of data.
From there: target cases per month × target cost per case = monthly budget. If the budget that produces is more than you can fund from current cash, start with fewer case types and one channel, rather than spreading thin across five.
Mistakes That Distort the Number
- Counting referrals as marketing cases. If a former client sends their cousin, that's not a Google Ads case, even if the cousin Googled your name first.
- Ignoring intake costs. The answering service is part of acquisition.
- Comparing to TV firms. National advertisers run on different economics and longer horizons. See TV and billboards vs. digital.
- Judging too early. A new personal injury PPC campaign needs time to collect data before its cost per case means much.
More on the general method is in our insight on cost per signed case and our guide to legal marketing ROI.
Frequently Asked Questions
There's no single good number, because it depends on your market, case types and typical fees. A defensible target comes from your own history: take your typical attorney's fee for a case type and decide what share you'll spend to acquire one. A cost per case that looks high may still be worthwhile if the channel brings in more serious injuries.
Add all costs for a marketing channel over a period (ad spend, management fees, tracking and intake costs tied to it) and divide by the number of signed fee agreements that channel produced in the same period. Exclude referrals and repeat clients that didn't come through the channel, and decide upfront how to count cases that are later dropped.
Personal injury volumes per channel are usually small, so a couple of signed cases more or less swings the result sharply. Case value also varies enormously from one signed case to the next. That's why it's better to judge PI channels over six to twelve months and to track case quality alongside the count.
Cost per case. Cost per lead tells you what you paid to get a phone to ring. Cost per signed case tells you what you paid for a client, which is what matters. Two lead sources with the same cost per lead can produce very different costs per case depending on lead quality and how quickly your intake responds.