Most budget advice for law firms starts with a percentage of revenue. That number is easy to say and tells you almost nothing: it doesn’t know what your cases are worth, what it costs to sign one in your market, or how many calls your intake team can answer. A better budget is built from the bottom up, from the signed cases you want, and then checked against two ceilings. This guide shows the method, with a worksheet you can copy. It builds on our guide to cost per signed case, which is the input everything else depends on.
Why a percentage of revenue misleads
A percentage-of-revenue rule treats marketing as a cost to cap, not an investment to size. It has three problems.
- It looks backward. Revenue this year reflects cases signed in past years, often several years ago in injury work. The budget you need depends on the cases you want to sign now.
- It ignores price. Competition for legal advertising is heavy and rising. The American Tort Reform Association counted $4.1 billion spent on about 30 million legal services ads in 2025, up 47.4% on 2024 (ATRA). The same percentage buys fewer cases each year if prices rise.
- It ignores capacity. A budget that buys more leads than intake can answer wastes money twice: once on the click, and again on the case that signs with the firm that called back first.
The percentage can still be useful as an output. Once you’ve built the budget from cases, compare it with revenue as a sanity check. It just shouldn’t be the input.
The case-math method
The method has five inputs. Three come from your own records, and two from the market.
| Input | Where it comes from | What to watch |
|---|---|---|
| Target signed cases a month from paid channels | The partners’ plan | Separate paid targets from referrals and organic |
| Lead-to-sign rate | Your CRM: signed cases ÷ real leads, by channel | Use mature cohorts only (see cost per signed case) |
| Click-to-lead rate | Your ad accounts, checked against the CRM | Count real conversations, not every form fill |
| Cost per click | Your ad accounts, or Keyword Planner for new markets | Varies by keyword, practice and market |
| Value per signed case | Your resolved cases: average net fee by case type | Use two to three years of history |
The arithmetic is simple. Leads needed = target cases ÷ lead-to-sign rate. Clicks needed = leads needed ÷ click-to-lead rate. Media budget = clicks needed × cost per click. Cost per signed case = media budget ÷ target cases.
If you don’t yet have your own rates, start with published averages and replace them as your data arrives. The 2026 LocaliQ benchmarks, drawn from Google and Microsoft campaigns, put attorneys and legal services at a $9.87 average cost per click, a 5.55% conversion rate and a $131.63 cost per lead (LocaliQ). Those are averages across every legal category and every market. Personal injury in a large metro will usually sit well above them, and estate planning in a small town well below. Treat any average as a starting assumption, never a forecast.
Ceiling one: what a case is worth
The formula tells you what each case will cost. The first ceiling asks whether that is affordable.
Work out your average net fee by case type from resolved matters. For a rough injury example: the average auto bodily-injury liability claim was $28,278 in 2024 (Insurance Information Institute). At a one-third fee, that is about $9,400 of fee before case costs (our arithmetic). Your own number will differ by case mix, and your largest cases are worth many times the average.
Then decide what share of a case’s expected fee you are willing to spend to acquire it. That is a business decision for the partners, not a benchmark. Write it down. If the formula’s cost per signed case is above your ceiling, the budget is wrong, however much revenue the firm has.
For non-injury practices the same logic applies to a retained client: the average fee per matter, plus repeat and referral value if you can measure it.
Ceiling two: what intake can handle
The second ceiling is the one most budgets skip. Every lead the budget buys needs a person to answer it, qualify it, run conflicts, book a consult and follow up.
To size it, count three things from your own records:
- Minutes per lead: the average time intake spends on a lead from first contact to a yes or no, including callbacks.
- Coverage hours: the hours your phones are answered live, compared with when your leads actually arrive.
- Answer rate: the share of calls answered live. A budget that grows while the answer rate falls is buying cases for competitors.
Multiply leads by minutes per lead and compare it with the staffed hours you have. If the budget needs more hours than exist, either add intake staff before you add spend, or lower the target. Our law firm intake guide has a scorecard for checking the answer rate and follow-up.
The worksheet
Free worksheet: budget from case math
IllustrativeSame firm, same target: a better sign rate cuts the budget by 40%
| Step | Scenario A: 12% sign rate | Scenario B: 20% sign rate |
|---|---|---|
| 1. Target signed cases a month (paid search) | 10 | 10 |
| 2. Lead-to-sign rate (from your CRM) | 12% | 20% |
| 3. Leads needed (1 ÷ 2) | 83 | 50 |
| 4. Click-to-lead rate | 5.55% | 5.55% |
| 5. Clicks needed (3 ÷ 4) | 1,502 | 901 |
| 6. Cost per click (assumption) | $30 | $30 |
| 7. Media budget a month (5 × 6) | $45,060 | $27,030 |
| 8. Media cost per signed case (7 ÷ 1) | $4,506 | $2,703 |
| 9. Value per signed case (expected fee) | $9,400 | $9,400 |
| 10. Ceiling at 35% of expected fee | $3,290 | $3,290 |
| 11. Passes the value ceiling? | No | Yes |
| 12. Intake hours needed (3 × 45 minutes) | 62 hours | 38 hours |
| 13. Intake hours available for new leads | 50 hours | 50 hours |
| 14. Passes the intake ceiling? | No | Yes |
Scenario A fails both ceilings. The instinct is to cut the target. The better first move is usually intake: in this example, moving the sign rate from 12% to 20% means 33 fewer leads to buy and work each month for the same 10 cases. The intake fix also lowers the hours needed, so it clears the second ceiling at the same time.
If the sign rate is already as good as it will get, the other levers are the click side: drop keywords and areas that produce leads but rarely sign, and move the money to the ones that do. Only then lower the target.
How budgets differ by practice
Every practice changes the inputs. The method stays the same.
| Practice | Case value | Urgency and search behavior | What it does to the budget |
|---|---|---|---|
| Personal injury | High and uneven; a few large cases carry the year | Searches soon after an accident; the first firm to answer often signs | High cost per click; intake speed matters most; allow for long case timelines |
| Criminal defense | Moderate flat or staged fees | Very urgent, often at night or on weekends | Coverage hours are the real ceiling; budget by hour of day |
| Family law | Moderate, with retainers that can grow | Considered, with consults before retaining | Measure consult held and retained, not form fills |
| Estate planning | Lower per matter, often flat fees | Slow, research-heavy | Lower cost per click; content and local search carry more of the work |
| Employment (plaintiff) | High when a case fits, but many inquiries don’t | Deadline-driven once people learn of filing limits | Screening at intake decides the real sign rate |
| Immigration | Moderate, often flat fees | Trust-driven; Spanish matters in many markets | Budget for Spanish intake as well as Spanish ads |
| Lemon law | Fee shifting changes the economics | Searches by make, model and problem | Narrow keyword sets; check state rules on eligibility |
Read the table as a list of questions to ask about your own numbers, not as figures to copy.
How budgets differ by market
Cost per click is the input that changes most by market. Larger, more competitive markets have more advertisers bidding on the same searches. ATRA’s 2025 data show legal advertising concentrated in a handful of large media markets, with each of the top three drawing more than $100 million in tracked spending (ATRA).
To estimate your own market:
- Build a keyword list for each practice you plan to advertise.
- Run it through Google’s Keyword Planner set to your own target locations. Google says its forecasts depend on bid, budget, location targeting and other factors, so treat them as a range (Google).
- Put the middle of the range into the worksheet, then replace it with your actual cost per click after the first month.
- If you serve several markets, run the worksheet once per market. A blended cost per click hides the market where you’re losing money.
Local Services Ads work differently: you pay per valid lead rather than per click, against an average weekly budget, with a monthly maximum (Google). In the worksheet, skip steps 4 to 6 and multiply leads needed by your cost per lead. See our Local Services Ads guide for how lead charges and credits work.
Pacing the budget through the month
Google Ads budgets are set per day. Google may spend up to twice your average daily budget on a given day, but no more than 30.4 times it in a month (Google). So to spend a monthly budget, divide it by 30.4 to get the daily figure. Check pacing weekly against intake: a good week for clicks is a bad week if no one answered the calls.
When to add a channel
Add a channel when one of these is true, and not before:
- The current channel is at its spend ceiling. Each extra dollar now buys cases above your cost ceiling. The marginal cost per signed case, the change in cost divided by the change in cases between two spend levels, tells you where that is (The Probative Standard).
- Intake has spare capacity that the current channel can’t fill at an acceptable cost.
- A practice or language is uncovered, such as Spanish-speaking callers in your market.
Give the new channel its own line in the worksheet, its own target, and a test plan. A channel can look cheap because it takes credit for cases that would have signed anyway. A fair comparison, such as a holdout test by geography, is the way to tell. Our holdout test guide shows how to design one.
Common budgeting mistakes
- Budgeting by platform, not by case. “We spend $20,000 on Google” says nothing about what it buys.
- Using immature sign rates. Last month’s sign rate looks low because cases are still signing. Use mature cohorts.
- Blending markets and practices. One average hides the line that loses money.
- Forgetting fees. Compare your all-in cost per signed case, media plus fees plus tools, with what a case is worth.
- Raising spend before fixing intake. It is the most expensive way to grow.
What this means for your firm
- Write down the target in signed cases a month from paid channels, by practice.
- Pull three rates from your records: lead-to-sign, click-to-lead and cost per click, from mature cohorts.
- Set your value ceiling as a share of expected fee per case, and have the partners sign off on it.
- Measure intake capacity in minutes per lead and staffed hours, and fix the answer rate before you raise spend.
- Run the worksheet per practice and per market, and revisit it monthly.
Probative is AI-first SEO and ads for law firms. Every plan we run is built and reported this way, in signed cases from your own records, every Monday. Our fees are flat and published on the pricing page, never a percentage of ad spend. For a fuller view of what marketing costs beyond media, see what law firm marketing costs, and for the reporting itself, signed-case reporting.
Marketing information, not legal, tax or accounting advice. Fee arrangements and what you spend to acquire cases are your firm’s decisions, within your state’s rules.