The percentage-of-revenue framework answers the wrong question. Here is the calculation that actually determines what your PI firm should spend.
A PI attorney in Atlanta sent me a screenshot of the marketing budget advice she had received from two different consultants. The first said to spend 5 percent of gross revenue on marketing. The second said the number should be 10 percent. Her revenue last year was $1.4 million. She was trying to decide whether to spend $70,000 or $140,000. The problem is that neither number tells her what she needs to know. Neither answers the only question that matters: what will it cost to sign the number of cases you need to sign next year?
The percentage-of-revenue framework was borrowed from consumer goods marketing, where it makes some sense. A consumer brand spends a portion of its revenue on advertising to maintain or grow market share. Revenue is a reasonable proxy for scale, and scale is correlated with what you need to spend to stay visible.
PI law does not work this way. PI revenue is lumpy, case-dependent, and structurally disconnected from marketing need. Consider two firms with $1 million in gross revenue last year. Firm A closed two trucking cases worth $500,000 each. Firm B closed 25 auto accident cases at $40,000 each. Both apply the 10 percent rule and arrive at a $100,000 marketing budget for next year. But Firm A needs a strategy to find high-value trucking cases, which may require different channels, different creative, and different intake qualification than Firm B’s volume-based auto accident practice. The same budget number for completely different marketing problems produces completely different results.
Ben Glass at Great Legal Marketing has made this point consistently for over a decade. Budget from the outcome backward, not from the revenue forward. Decide what it costs to produce a signed case from marketing, decide how many signed cases from marketing you need to hit your growth target, and multiply. That is your budget. Last year’s revenue is irrelevant to that calculation.
The benchmark data is still useful, but as a sanity check rather than a planning tool. Knowing that PI firms typically spend 10 percent of revenue on marketing tells you whether your current spend is in the range of what similar firms spend. It does not tell you whether that spend is producing the right outcome at the right cost.
Research from LEXGRO and PracticeProof looking at 2026 law firm marketing benchmarks confirms what most experienced PI marketers already know: the firms spending 15 to 20 percent of revenue on marketing are growing. The firms spending 5 percent are not. But that correlation does not mean spending more causes growth. It means the firms that have a system that is working are confident enough in their cost per signed case to invest more into it. The growth comes from the system working, not from the percentage being right.
If your cost per signed case is $4,000 and your average fee is $60,000, you should be spending as much as you can afford because every dollar into the system produces an obvious return. If your cost per signed case is $18,000 on a $40,000 average fee, spending more does not improve the ratio. Fixing the conversion problem does.
Here is the calculation. Work through it with your own numbers before reading the rest.
Step one: what is your average attorney fee on a signed PI case from marketing? Use your last 12 months of signed cases that came from a marketing channel, not referrals. Average the fees on those cases.
Step two: multiply your average fee by 0.07. That is your target cost per signed case at a 7 percent ratio, which is a healthy benchmark for most PI markets. More competitive markets or higher-value case types can sustain up to 10 percent without the math becoming unfavorable.
Step three: how many new cases per month from marketing do you need to hit your revenue target? Write that number down.
Step four: multiply your target cost per signed case by your target monthly case volume. That is your marketing budget.
Example: $70,000 average attorney fee. $70,000 multiplied by 0.07 equals $4,900 target cost per signed case. Eight cases per month from marketing multiplied by $4,900 equals $39,200 per month. That is a budget that has a logical connection to what the firm is trying to achieve. It is also verifiable. If you spend $39,200 and sign eight cases, the system is working. If you sign four, the conversion rate is breaking down somewhere and more spend is not the fix.
The percentage model also misses the phase of your firm’s development. A firm that just launched needs to spend more than 10 percent of its current revenue on marketing because its current revenue does not reflect the case volume it is trying to build toward. A firm that is holding steady at a comfortable case volume that covers overhead and partner distributions needs to spend differently than a firm that is trying to double its case volume in 18 months.
These are not subtle differences. They require fundamentally different budget logic. The newly launched firm should budget from its target revenue, not its current revenue. The firm in growth mode should budget from the incremental cases it needs, not from a percentage of what it already makes. The stable firm should budget to defend and maintain the channels that are working rather than experimenting with new ones.
None of these decisions come out of a percentage of last year’s revenue. They come from understanding the cost per signed case your system is currently producing, what it should be producing, and how many cases you need to close the gap between where you are and where you want to be.
Related reading
For dollar-amount budgets by firm size, read How Much Should a PI Law Firm Spend on Marketing in 2026. To understand the full cost breakdown of a PI marketing system, read How Much Does PI Lawyer Marketing Actually Cost in 2026. To see what your budget should be producing and why it may not be, read Why Your PI Firm Is Spending on Ads and Not Seeing Cases.
Industry data shows PI firms average 10 percent of revenue on marketing, with aggressive growth firms in competitive markets spending 15 to 20 percent. High-growth law firms collectively spend 16.5 percent compared to 5 percent for no-growth firms. The more useful question is what your cost per signed case should be as a percentage of your average attorney fee. A target of 5 to 10 percent of average fee per signed case is the correct benchmark. Work from that number backward to your budget rather than forward from your revenue.
No. The 5 percent rule was borrowed from consumer brand marketing and does not apply to PI law, where revenue is lumpy, case values vary widely, and the marketing need for a given quarter is determined by case volume targets rather than by what you earned before. A PI firm that closed two high-value trucking cases last year has very different marketing needs from a firm that closed 30 mid-value auto accident cases, even if both had similar gross revenue. Budget from what you need to achieve, not from what you already earned.
Take your average attorney fee on signed PI cases from marketing. Multiply by 0.07 to get a target cost per signed case at 7 percent. Then multiply your target cost per signed case by the number of cases you want to sign from marketing each month. That is your budget. Example: $60,000 average fee multiplied by 0.07 equals $4,200 target cost per signed case. Ten cases per month multiplied by $4,200 equals a $42,000 monthly marketing budget. This number has a direct logical connection to your case volume target. The percentage of last year’s revenue does not.
A new PI firm should almost always spend more than the industry percentage average as a proportion of current revenue, because its current revenue does not reflect the case volume it is trying to build. Budget from the target revenue the firm needs to sustain itself and grow, not from its first-year or second-year billings. An established firm trying to hold its current volume steady can spend less as a percentage because it has existing channels and referral relationships supplementing paid marketing. The phase of the firm’s development determines the right budget logic, not a universal percentage rule.
A free 15-minute session where we calculate your current cost per signed case, show you what it should be, and build the budget number that connects directly to your case volume target.
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