Cost per signed case
How does a law firm work out its cost per signed case?
The formula, which costs belong in it, why cost per good lead beats cost per lead, how to handle cases that sign months later, and how to tell if your number is good.
By Santiago Alvarez, Founder, Ad Hoc Digital
Last updated
The short answer
If you read one part of this page, read this.
Cost per signed case is what you spent on a marketing channel divided by the cases that channel signed. Work it out per channel, count the cases against the month their leads came in, and compare the result with what a case is worth to you.
The arithmetic is one line. The judgment is in the inputs: which costs you include, which leads you count as good, and how long you wait for slow cases to sign. Get those wrong and a channel that works looks like one that doesn't.
Below: three versions of the formula, the costs that belong in each, the step in the middle that most firms skip (cost per good lead), how to handle the lag, and how case value decides what a good number is. We work with law firms across the US and Canada, and also in Australia and the UK.
The formula
Spend divided by signed cases, in one of three versions.
Pick the version that matches the question you're asking. Ad spend alone tells you whether a channel works; the fuller versions tell you whether the whole operation does.
| Version | What you divide | Answers the question | Use it when |
|---|---|---|---|
| Ad spend only | What you paid Google or Meta for that channel, after any lead credits | Is this channel worth more budget? | Comparing channels month to month |
| Marketing cost | Ad spend plus what you pay to run the channel: agency or marketer, tracking, creative | Is the channel worth what it really costs us? | Deciding whether to keep, change or drop a channel |
| Acquisition cost | Marketing cost plus intake: staff time, answering service, CRM | What does a new client cost the firm in total? | Setting fees, hiring, and yearly planning |
Most month-to-month decisions only need the first version, because the other costs don't change much with each extra dollar of ad spend. Use the fuller versions a few times a year, or whenever someone asks whether marketing as a whole is paying off.
What goes in
Put each cost with the channel that caused it, and leave out what would happen anyway.
A cost belongs to a channel if it would stop when the channel stops. Your office rent wouldn't; your landing pages and tracking numbers would.
- Ad spend, net of credits
Take it from each platform's billing page, per channel. On Local Services Ads, Google credits low-quality leads automatically, in most cases within 30 days, so the month's real spend isn't final until those credits land. Automatic credits aren't available to advertisers in EMEA, which includes UK firms.
- Lead vendors and directories
A paid directory listing or a bought lead is a channel like any other. Give it its own line, and its own tracking number, so its signed cases can be counted.
- Running the channel
Whatever you pay an agency, freelancer or in-house marketer for that channel, plus channel-specific tools such as call tracking numbers, landing pages and video shoots. Split shared costs by a simple rule (time spent, or share of spend) and keep the rule the same each month.
- Intake
Staff time, an answering service, the CRM. These belong in acquisition cost, not channel cost, because they serve every channel. They matter when a channel sends many leads that take a long time to screen.
- Not marketing at all
Referral fees between lawyers, where your rules allow them, and the cost of the work itself. Keep them out, or the number stops comparing like with like.
The middle step
Between cost per lead and cost per signed case sits cost per good lead.
A good lead is a real person with a matter you handle, in the area you serve. It's the earliest number that predicts signed cases, and the one we judge new campaigns on.
| Number | Divide spend by | Shows up | Good for |
|---|---|---|---|
| Cost per lead | Every call, form and message | Days | Spotting a channel that's broken or flooding |
| Cost per good lead | Leads relevant to the firm's services and area | Days to a week | Judging new campaigns and keywords early |
| Cost per signed case | Cases signed from those leads | Weeks to months | Deciding where the budget goes |
"Relevant to services" is the only positive label we put on a lead, because it's all a call or form can tell you. Whether that person signed is something only the firm knows, so intake marks it in the CRM. We never label a lead converted from the lead alone.
Cost per lead on its own misleads in both directions. We've seen a cheap channel send a month of leads where none were good, while a pricier channel for the same firm sent leads that were good. Judged on cost per lead, the wrong one wins. And we don't judge a search campaign's lead rate on fewer than about 40 clicks, because below that a single good or bad day decides the answer.
The lag
Credit each signed case to the month its lead arrived, not the month it signed.
Cases sign days, weeks or months after the first call. If you divide this month's spend by this month's signings, you're comparing two different groups of people.
The fix is to track by intake month, sometimes called a cohort. Every lead keeps the month it arrived. When it signs, the signing counts toward that month's spend. A month's cost per signed case then improves as late cases come in, and you can watch it settle.
| Intake month | Signed by month end | Signed after 60 days | Signed after 90 days |
|---|---|---|---|
| July | 3 ($1,333 each) | 6 ($667 each) | 7 ($571 each) |
| August | 2 ($2,000 each) | 5 ($800 each) | Not yet known |
| September | 4 ($1,000 each) | Not yet known | Not yet known |
Read that way, August only looked weak at month end; at 60 days it was not far behind July. Judging on the month-end column alone would have cut a channel that was working. Our guide on how long marketing takes covers typical lags by channel.
By channel
Never blend channels into one number.
A blended cost per signed case can look fine while one channel carries another. Work it out per channel, then look at the blend for the firm as a whole.
- Paid channels: straightforward
Local Services Ads, Google search ads and Meta ads each have a bill and their own leads. With tracking numbers and source fields in the CRM, each gets its own cost per signed case. Our attribution guide covers getting the source right.
- Reputation, AI search, social and referrals: no click cost
These cost time and service fees rather than ad spend, and they build over months. Use the marketing cost version and a longer window, such as a quarter. Expect the number to look poor early and improve as the work compounds.
- Referral partners
The cost is mostly time. Count the cases they send, and treat the cost per case as low and lumpy rather than as zero.
Real results show how far apart channels can sit. A DUI defense solo who had tried SEO, PPC, social and bought leads generated $13,500 from $600 in ad spend in 12 days on Local Services Ads. On Google search ads, a Toronto real estate solo starting from zero online presence brought in $10,875 in its first week, on just over $300 of ad spend. Individual results, not promises.
What's a good number
A good cost per signed case is a small slice of what a case is worth to you.
There's no industry benchmark worth using, because case values differ by a factor of a hundred across practices. Start from your own average fee and work out what you're willing to pay to win one.
| Fee model | Compare against | Watch for |
|---|---|---|
| Flat fee (estate plans, uncontested matters, many immigration filings) | Your average flat fee | Volume: a low fee means cost per signed case has to stay low |
| Hourly with a retainer (family, business, litigation) | Average first retainer, then average total billed | Clients who sign but pay a small first retainer |
| Contingency (injury, some employment) | A realistic expected fee, discounted for cases that don't recover | The long wait between signing and payment |
Case value changes everything. For one injury firm, a single $250,000 settlement meant $82,000 in revenue, which paid for the entire system more than 10 times over after 18 months of consistent cases. A cost per signed case that would sink an estate planning practice can be cheap in that context. Our personal injury marketing page covers how those cases are won.
Capacity is the other limit. A low cost per signed case doesn't help if the firm can't take more matters, and a rising one is fine if the extra cases are still well worth it. Our Google Ads budget guide works budgets back from signed cases.
A worked example
A hypothetical family firm working out all three versions.
Invented numbers for a single 90-day look, to show how the versions differ. Not a client result, and not a benchmark.
The lesson is in the last step: the channel with the higher cost per signed case was the better buy once case value came in. Our family law marketing page covers how those clients choose a firm.
This month
A monthly routine that keeps the number honest.
Once a month, a few days in, after billing has settled. Local Services Ads credits for the month before may still be arriving, so revisit that line the following month.
Pull net spend per channel
From each platform's billing page, after credits. Add channel running costs if you track the fuller version.
Count good leads per channel
From the CRM, filtered to leads relevant to your services. Note the cost per good lead next to last month's.
Update signed cases by intake month
Add the month's signings to the month each lead arrived. Our intake metrics guide covers the stages behind this.
Compare to case value
Average fee or retainer per channel. Note any channel where cost per signed case is rising faster than value.
Move budget slowly
Shift toward what signs, in steps, and judge each change over at least a month. A single month of signings is too small to swing a budget on.
Our systems work sets up the CRM stages and source fields this needs, and the reports come from it. The firm owns all of it.
Common mistakes
Where firms go wrong.
The cost per signed case mistakes we see most often in the numbers firms bring to us.
Dividing this month's spend by this month's signings
The cases that signed this month mostly came from earlier leads. Track by intake month instead.
One blended number for the whole firm
A strong referral month can hide a paid channel that signed nothing. Work it out per channel.
Using gross spend on Local Services Ads
Credits for low-quality leads arrive later. Use spend net of credits, or the channel looks dearer than it is.
Judging a new campaign on signed cases in week two
Too early. Use cost per good lead until enough time has passed for cases to sign.
Ignoring case value
A low cost per signed case can belong to the channel bringing small matters. Compare against what each case is worth.
Real results
What this looked like for real firms.
Three results that show the math from different directions: a DUI solo on Local Services Ads, a new Toronto real estate firm on Google search ads, and one injury settlement that paid for the system many times over.
Identifying details are anonymized to protect our clients. Individual result, not a promise or prediction of any specific outcome for your firm.
FAQ
Questions lawyers ask us.
Straight answers to the questions that come up most.
What is cost per signed case?
It's the marketing spend for a channel divided by the cases that channel signed. It's also called cost per acquisition or client acquisition cost, though some firms use those terms to include intake costs too. Whatever you call it, say which costs are included and keep it the same each month.
What's a good cost per signed case for a law firm?
It depends on what a case is worth to you. A number that's cheap for a contingency injury practice can be ruinous for flat-fee estate plans. Start from your average fee and capacity rather than an industry figure. Our guide to law firm marketing costs covers typical ad spend by platform.
Should cost per signed case include our agency's fee?
For channel comparisons month to month, ad spend alone is usually enough. To decide whether a channel is worth keeping, include what you pay to run it, agency or in-house. To set firm-wide budgets, include intake costs as well.
How long should we wait before judging a channel on signed cases?
Long enough for most of a month's leads to have had a chance to sign: often 60 to 90 days, longer for contingency work. Until then, judge on cost per good lead. A search campaign needs about 40 clicks before its lead rate means anything.
How do we handle a case that came from two channels?
Pick one rule and keep it, usually the source of the first inquiry, and note the second source in the record. Changing rules month to month makes the numbers useless. Our attribution guide covers first and last touch in more detail.
Can Google Ads optimize for signed cases?
Partly. You can import signed cases from your CRM as offline conversions, but Google's conversion window is 30 days by default and at most 90, and many cases sign later than that. We import an earlier stage for bidding and judge on signed cases. Our Google Ads call tracking guide explains the setup.
Can you work out our cost per signed case?
If your CRM has a source and an outcome on each lead, yes, and if not, setting that up is the first step. Schedule a consultation and bring last quarter's spend by channel.
Where we do this
The services this guide touches.
What this looks like when we run it for a firm, with a demo for your practice on each page.
Sources
Where these facts come from.
Official pages we read when writing this page. Platforms and rules change, so check the current version before you act on any of it. This is marketing guidance, not legal advice.
Written by
Founder of Ad Hoc Digital. Leads strategy and works directly with every client firm on AI search, Local Services Ads, Google Ads and Meta ads.
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