Copy for Originals · Personal injury Google Ads
A personal injury law firm should budget at least 3 times its expected cost per lead each month for Google Ads. Below that, a month with zero leads can’t be told apart from bad luck, so the firm can’t tell whether the campaign works. This is the PPC Gumball Rule from Copy for Originals, applied to law firm budgets.
Minimum monthly budget = 3 × cost per click ÷ conversion rate
At $100 a click and a 5% conversion rate, a lead costs $2,000 and the minimum budget is $6,000 a month. At $200 a click, it’s $12,000.
Educational only, not legal advice. This guide covers Google Ads Search campaigns for personal injury lead generation. Plan with your own cost per click, not an industry average.
The PPC Gumball Rule, from Copy for Originals, says that if a Google Ads campaign spends 3 times its expected cost per conversion without a single conversion, bad luck explains it only about 5% of the time, so something is probably wrong. In clicks, the checkpoint is 3 ÷ your expected conversion rate: 60 clicks at 5%, 120 clicks at 2.5%.
For a personal injury firm, that makes 3 × the expected cost per lead the smallest monthly budget that can tell a working campaign from a broken one. The rule names a rule of thumb experienced advertisers already use and adds a 2× “yellow light” for when protecting budget matters more than certainty. Check your own numbers with the PPC Gumball Rule calculator.
The minimum useful Google Ads budget for a personal injury law firm is 3 × its expected cost per lead per month, where expected cost per lead = cost per click ÷ conversion rate. That’s the PPC Gumball Rule checkpoint: the spend at which zero leads stops being plausible bad luck (about a 5% chance). With less, the firm can still get leads, but a month with none tells it nothing.
The table gives the minimum monthly budget for common cost-per-click and conversion-rate combinations. The conversion rate is the share of ad clicks that call or submit a form.
| Cost per click | 3% convert | 5% convert | 8% convert | 10% convert |
|---|---|---|---|---|
| $50 | $5,000 | $3,000 | $1,875 | $1,500 |
| $100 | $10,000 | $6,000 | $3,750 | $3,000 |
| $200 | $20,000 | $12,000 | $7,500 | $6,000 |
| $300 | $30,000 | $18,000 | $11,250 | $9,000 |
The minimum gets you a verdict, not a caseload. To plan for a number of leads, budget leads wanted × cost per lead on top, and give Smart Bidding room: the Lead Gen Search Campaign Checklist sets a daily budget of at least 3× the target cost per lead once Target CPA is on.
A personal injury lead from Google Ads costs the firm’s cost per click divided by its conversion rate. At $100 a click and 5%, that’s $2,000. At $200 a click and 8%, it’s $2,500. The two numbers that matter are both in the firm’s own account.
| Cost per click | 3% convert | 5% convert | 8% convert | 10% convert |
|---|---|---|---|---|
| $50 | $1,667 | $1,000 | $625 | $500 |
| $100 | $3,333 | $2,000 | $1,250 | $1,000 |
| $200 | $6,667 | $4,000 | $2,500 | $2,000 |
| $300 | $10,000 | $6,000 | $3,750 | $3,000 |
Find your cost per click in Google Ads under Campaigns (the Avg. CPC column). For a new account, use Keyword Planner’s “Top of page bid (high range)” for the keywords you’ll bid on. Don’t plan with an industry average: averages mix cheap long-tail searches with the contested keywords that actually bring injury cases, so they can be several times too low.
Usually not. At $100 a click, $1,500 buys 15 clicks. At a 5% conversion rate, the chance of zero leads from 15 clicks is 0.9515, about 46%, so nearly half of months would bring nothing even with a campaign set up well. The firm can’t tell bad luck from a broken campaign, and most firms in that spot quit before they find out.
A small budget works better on cheaper ground: Local Services Ads (pay per lead), longer and more specific keywords, or a smaller service area where clicks cost less. Run the numbers again with the cheaper cost per click.
Enter your cost per click, expected conversion rate, and how many leads you want a month.
Enter your numbers to see your budget.
Google Ads is worth it for a personal injury firm when a signed case is worth several times what it costs in ads to sign one. Cost per signed case = cost per lead ÷ the share of leads that sign. At a $2,000 cost per lead and 1 in 5 leads signing, a case costs $10,000 in ads. Compare that to the firm’s average fee per case.
Track signed cases, not just leads. Import them into Google Ads as offline conversions so Smart Bidding learns which searches bring cases, not just calls.
It varies more with city and cost per click than with firm size. The useful question is the minimum: 3 × the firm’s expected cost per lead per month, by the PPC Gumball Rule. At $100 a click and 5%, that’s $6,000 a month; at $300 a click, $18,000.
Until it has spent 3 × its expected cost per lead, however many days that takes. A firm spending $200 a day with a $2,000 expected cost per lead reaches the $6,000 checkpoint in 30 days.
Check conversion tracking first (submit a test lead), then the landing page form and phone number, the search terms report and location settings. The PPC Troubleshooter walks through each check.