Cost per signed case is what a law firm pays in marketing for each case it actually signs: total marketing spend divided by the cases that spend produced.
It decides whether a channel keeps its budget line, because leads and clicks are only worth what they turn into.
This is the calculation that sits under law firm marketing cost, the budget guide.
The cost per case acquisition formula
Cost per case acquisition for law firms comes down to one division: everything the firm spent on marketing in a period, divided by the cases signed from that period's marketing.
Cost per signed case
Count every acquisition line in the numerator: agency and consultant fees, ad spend, directory subscriptions, call tracking, and freelance help.
Leave out what the firm spends serving the case after signing; that belongs to margins.
Tag each lead at intake and count the cases those leads later produced, since a case usually closes days or weeks after the inquiry.
A worked example, illustrative throughout: a firm spends $6,000 in a month, $3,000 on paid ads, $2,500 on a marketing retainer, $500 on tools and directories.
The month's 120 leads produce 60 held consultations and 12 signed cases.
$6,000 divided by 12 signed cases is $500 per signed case.
The same month's cost per lead was $50, which is the number most reports stop at.
From cost per lead to cost per signed case
Cost per lead divides the same spend by everyone who raised a hand; cost per signed case divides it by the people who became clients.
The distance between the two is conversion.
Illustrative: one month, one firm
Each step in that funnel multiplies the lead cost into the case cost.
What each channel charges per lead is its own question: Google's Local Services Ads bill per valid lead (calls, messages and bookings), with prices that vary by location, job type, lead type and bidding mode, and Google publishes no lawyer-specific lead prices.
The lead-price catalog is in law firm cost per lead; this page takes the lead price as given.
Split the number by channel
One blended number hides which channel carries the firm.
Compute it per channel: the channel's spend divided by the cases signed from leads that channel produced.
It only works if intake records a lead source on every call and form.
Keep the channels separate for a second reason too: Google's own search documentation says advertising with Google has no effect on a site's presence in search results.
A channel that produces leads but never cases is cheap to cut once the source tag exists.
The multiplication that decides the number
The version of the formula worth memorizing: cost per signed case equals cost per lead divided by the product of two shares, the leads that book and the booked consultations that sign.
In the example above, $50 per lead, 60 of 120 leads booking, and 12 of 60 signing: $50 ÷ (0.5 × 0.2) = $500.
Every point of conversion you add divides the same spend across more cases.
In Clio's 2019 Legal Trends Report, 57% of consumers who had shopped for a lawyer said they contacted more than one firm, 44% believed they needed to talk to more than one lawyer, and 42% said that if they liked the first lawyer they spoke with, they would not need to speak with others.
The same survey found 64% of people who contacted a firm they did not hire said the firm never responded by phone or email, and 65% said they got no indication of what to do next, with respondents free to pick several reasons.
Clio's 2024 mystery-shopping update measured 41% of firms giving rate information on calls, only 12% able to estimate total cost, and 36% explaining the process and next steps.
Whether a firm quotes fees on intake is its own call under its state's fee rules, not something a benchmark decides.
The rate itself, how to measure it and what moves it, is the whole subject of consultation-to-signed-case rate.
Illustrative: the same $6,000 at two signing rates
At a 20% signing rate the month's 60 consultations produce 12 cases at $500 each; at 30% they produce 18 cases at roughly $333.
The spend never changed, and neither did the leads.
Client acquisition cost for law firms
Client acquisition cost for law firms is the wider version of the same division: everything that goes into winning clients, divided by the clients won.
That numerator can include intake staffing and software, referral entertainment and bar memberships, and the owner's own hours, not just the marketing budget.
General marketing writing calls the same figure "customer acquisition cost", or CAC; for a firm the unit is a client, and most consumer practices get a sharper read by counting signed cases.
Pick a numerator once and keep it stable quarter to quarter.
What the wider figure buys is honesty about channels that look cheap only because their costs sit on someone's calendar instead of a card.
What a signed case is worth, and cost per retained client
A cost per signed case cannot be judged until it sits next to what the case pays.
For contingency practices the fee comes out of the recovery, and what the firm keeps is the fee less the costs the agreement says come out of it.
ABA Model Rule 1.5(c) says a contingent fee agreement must be in a writing signed by the client, stating the percentage or percentages charged on settlement, trial or appeal, which expenses are deducted, and whether expenses come out before or after the fee is calculated.
States adopt their own versions (Ohio's also requires the lawyer's signature), so the firm's own state rule controls.
The rule describes what the agreement must say; the number this math needs is the fee the firm actually keeps per matter, net of costs and any referral fees paid.
For hourly and flat-fee practices the figure is simpler: whatever the matter pays.
Cost per retained client is the same spend divided by the unique clients retained rather than by matters.
It matters where one client can return or refer, which is the doorway to law firm client lifetime value.
Why no vendor publishes a price per signed case
A review of published law firm marketing pricing pages in October 2026 found six models in use: monthly retainers, management fees as a percentage of ad spend with a floor, one-time flat fees for builds and setup, per-piece content fees, pay per lead, and per-call intake pricing.
None of those pages published a pay-per-signed-case price.
Agencies do put cost-per-signed-case figures in case studies, but a results claim about one client is not a price anyone sells at.
The rules explain the gap.
ABA Model Rule 7.2's comments, as amended in August 2018, say lawyers may pay for advertising, including online directories and internet ads, and may pay employees, agents and vendors who provide marketing or client-development services, including website designers.
ABA Model Rule 5.4(a), in the ABA's text as of January 2023, says a lawyer or firm shall not share legal fees with a nonlawyer outside narrow listed exceptions, and Rule 5.4(c) bars letting someone who recommends, employs or pays the lawyer direct the lawyer's professional judgment.
A per-signed-case fee or a share of legal fees raises Rule 5.4 and Rule 7.2 questions, how a given structure is treated varies by state, and the Model Rules bind no one until a state adopts them.
More Booked Cases prices flat monthly, $2,500 a month for CRO or local SEO and $5,000 for both, and does not offer per-case pricing; whatever any vendor proposes, put the structure in front of your state bar's ethics counsel or an ethics lawyer first.
Judging your number
No published, method-disclosed benchmark says what a law firm's cost per signed case should be, and this page quotes none for exactly that reason.
Be skeptical of any per-case benchmark without a named survey or a disclosed method.
Judge the number three ways instead.
- Against the net fee. If a signed matter nets the firm $4,000 after costs (illustrative), a $500 acquisition cost spends 12.5% of it.
- Against the trend. One month is noise; six months by channel is a decision.
- Against the alternative. The same spend in the firm's best channel is the real comparison, which is the step into law firm marketing ROI.
Compute it monthly, per channel, from tagged leads, and judge it against what a signed case nets the firm: that is the whole discipline.
Frequently asked questions
What is a good cost per signed case for a law firm?
No published, method-disclosed benchmark sets one. The workable test is whether the number sits comfortably below what a signed case nets your firm after costs and any referral fees, checked channel by channel.
How is cost per signed case different from cost per lead?
Cost per lead divides spend by everyone who inquires; cost per signed case divides the same spend by the cases actually signed. The gap between them is your booking and signing conversion, which is why the signed-case number is never the smaller one.
What is client acquisition cost for a law firm?
The wider version of the same division: all spending and time that goes into winning clients, including intake staffing, software and the owner's hours, divided by clients won. Cost per signed case normally counts marketing only.
How do I lower my cost per signed case?
Two levers: sign more of the leads you already pay for, or cut spend on channels whose leads never sign. The first is conversion work on the website and faster follow-up in intake; the second needs a lead-source tag on every call and form.
How do I calculate cost per signed case for each channel?
Divide the channel's spend by the cases signed from that channel's leads, using the lead source recorded at intake. If intake does not record a source, the tag is the first thing to fix.