Step-by-Step Formula to Calculate Your Law Firm's Advertising Budget

Maximize Your Marketing ROI

You know that attracting high-quality clients is crucial for your legal practice's success. However, many solo practitioners and small to mid-sized law firms struggle with determining the right ad budget. 

But how much should you invest in digital advertising to achieve optimal results? 

Today, we'll explore a data-driven approach to calculating your ad budget that can help you make informed decisions and maximize your return on investment.

This blog post will walk you through a step-by-step formula for calculating your law firm's ad budget, ensuring a strategic and cost-effective approach that aligns with your business goals and ethical standards.

This 9 step approach provides a comprehensive method for determining an appropriate ad budget based on various financial metrics:

1. Calculate Average Case Value (ACV)

ACV: The average revenue generated per client or case.

Formula:

ACV = Total Revenue Per Month / Number of Cases Per Month

Example:

If your firm generates $100,000 per month and handles 20 cases per month, your average case value will be $5,000:

ACV=100,000/20=$5,000

2. Determine Client Lifetime Value (LTV)

LTV: The total revenue a client generates over the duration of their relationship with the firm.

If the ACV represents the average revenue per case and the average client has multiple cases, multiply ACV by the average number of cases per client to determine LTV.

Formula:

LTV = ACV × Average Number of Cases per Client 

Example:

If ACV is $5,000, average client has 2 cases:

LTV = $5,000 × 2 = $10,000

3. Calculate Customer Acquisition Cost (CAC)

CAC: The amount spent on marketing and sales to acquire a new client per month.

Formula:

CAC = Total Sales and Marketing Expenses / Number of New Clients Acquired

Example:

If your total marketing and sales spend is $10,000 and you acquire 5 new clients:

CAC = 10,000 / 5 = $2,000

4. Calculate LTV:CAC Ratio

LTV:CAC Ratio: A measure of the value generated from a client relative to the cost of acquiring that client.

A higher LTV:CAC ratio indicates better profitability and efficiency in client acquisition.

Formula:

LTV:CAC Ratio = LTV / CAC 

Example:

If LTV is $10,000 and CAC is $2,000:

LTV:CAC Ratio = 10,000 / 2,000 = 5 

This means for every $1 spent on acquiring a client, the firm generates $5 in revenue.

For Legal Services industry, the benchmark LTV:CAC ratio is 4.5:1.

This means that for every dollar spent on acquiring a customer, law firms typically see a return of $4.50. This ratio indicates a profitable acquisition strategy, as a ratio closer to 3:1 or higher is generally considered strong across industries. However, a significantly higher ratio might suggest underinvestment in marketing, potentially missing opportunities for growth.

5. Set CAC Target Based on Desired LTV:CAC Ratio

To achieve a target LTV:CAC ratio (e.g., 5:1), set the CAC target accordingly.

Formula:

CAC Target = LTV / Desired LTV:CAC Ratio

Example:

If LTV is $10,000 and the desired LTV:CAC ratio is 5:1:

CAC Target = 10,000 / 5 = $2,000 

6. Calculate Your Marketing Budget

A marketing budget is a financial plan that outlines the amount of money allocated for marketing and advertising efforts over a specific period, typically a month, quarter, or year. This budget covers a range of activities aimed at attracting new clients, retaining existing ones, and promoting the law firm's services.

Formula:

Marketing Budget = (LTV / Target LTV:CAC Ratio) * Number of Desired New Clients

Example:

• LTV (Lifetime Value) = $10,000
• Target LTV:CAC ratio = 5:1
• Number of Desired New Clients = 10

Marketing Budget = (10,000 / 5) * 10 = $20,000

Interpretation:

Based on an LTV of $10,000 per client, a target LTV:CAC ratio of 5:1, and a goal of acquiring 10 new clients, the law firm should allocate a marketing budget of $20,000. 

This budget allows for spending up to $2,000 to acquire each new client while maintaining the desired 5:1 ratio between the lifetime value of a client and the cost to acquire them.

7. Calculate the Ad Budget

Use the marketing budget and CAC target to determine the appropriate ad spend.

Ad Budget Formula:

Ad Budget = Marketing Budget × CAC Target / ACV​

Example:

If your marketing budget is $20,000, CAC Target is $2,000, and ACV is $5,000:

Ad Budget = 20,000 × 2,000 / 5,000 = $8,000

8. Calculate Return on Ad Spend (ROAS)

Before scaling your ad budget, it’s crucial to calculate your ROAS to ensure your campaigns are profitable.

Formula:

ROAS = Revenue Generated from Ads / Ad Spend 

Example:

If your ad spend is $8,000 and it generates $32,000 in revenue:

ROAS = 32,000 / 8,000 = 4 

This means you earn $4 for every $1 spent on ads.

9. Scale Based on Performance 

Increase your ad budget incrementally as you identify successful campaigns that generate a high Return on Ad Spend (ROAS). 

a) The scaling formula assumes reinvesting all profits from ads back into the ad budget. 

Scaling Formula:

New Ad Budget = Current Ad Budget + (Current Ad Budget × ROAS)

Example:

If your current ad budget is $8,000 and you achieve a 4x ROAS:

New Ad Budget = 8,000 + (8,000 × 4) = 8,000 + 32,000 = $40,000  

This means, with a 4x ROAS, your new ad budget would be $40,000, as you are earning $4 for every $1 spent on ads, significantly increasing your capacity to scale your advertising budget based on the proven success of your current campaigns.

b) While ROAS can indicate successful campaigns, law firms should be cautious with sudden large increases in ad budget.

Increase your ad budget incrementally as you identify successful campaigns that generate a high Return on Ad Spend (ROAS).

Incremental Scaling Formula:

New Ad Budget = Current Ad Budget × (1+Δ) 

Where Delta Δ is a smaller increment (e.g., 10-20% of the current budget), based on ROAS performance.

Example:

If your current budget is $8,000 and you achieve a 4x ROAS: 

New Ad Budget = 8,000 × (1 + 0.20) = 8,000 × 1.20 = 9,600 

This means, with a 4x ROAS, your new ad budget would increase incrementally, reflecting proven success without overcommitting funds.

By following this formula, law firms can systematically determine their ad budget, ensuring efficient use of resources, and scaling based on proven performance. 

Important Notes:

1. KPI Tracking: Throughout this process, it's crucial to continuously track and analyze key performance indicators (KPIs) such as click-through rates, conversion rates, cost per click, and cost per acquisition. These metrics will help you refine your ad strategy and budget allocation over time.
2. Flexibility and Adaptation: This formula should be used as a guideline and may need to be adjusted based on specific firm circumstances, practice areas, and local market conditions. Regularly review and update your calculations to reflect changes in your business and market environment.
3. Continuous Optimization: Ad budgeting is an ongoing process. Regularly review your campaigns' performance and be prepared to adjust your budget and strategies accordingly.
4. Compliance: Ensure all your advertising efforts comply with legal and ethical standards set by your local bar association and other regulatory bodies.

By following this formula and keeping these important considerations in mind, law firms can develop a more effective and adaptable approach to their digital marketing budget allocation.

Remember, these calculations provide a starting point – continually monitor and adjust your strategy based on real-world performance. Effective digital marketing is an ongoing process that requires continuous analysis, optimization, and adaptation.

With a thoughtful approach to ad spending, you'll be well-positioned to attract high-quality clients and grow your practice efficiently.

Summary of Steps for Law Firm Ad Budget Calculation

1. Calculate Average Case Value (ACV):
   Determine the average revenue generated per case by dividing the total monthly revenue by the number of cases per month.
2. Determine Client Lifetime Value (LTV):
   Calculate the total revenue a client generates over their relationship with the firm by multiplying the ACV by the average number of cases per client.
3. Calculate Customer Acquisition Cost (CAC):
   Find the cost to acquire a new client by dividing total sales and marketing expenses by the number of new clients acquired.
4. Calculate LTV:CAC Ratio:
   Measure profitability by dividing the LTV by the CAC to understand the value generated per client relative to the cost of acquisition.
5. Set CAC Target Based on Desired LTV:CAC Ratio:
   Establish a target CAC to maintain a desired LTV
   ratio, ensuring efficient spending on client acquisition.
6. Calculate Your Marketing Budget:
   

   Determine the overall marketing budget needed to reach your client acquisition goals while ensuring that your spending aligns with your financial targets.

7. Calculate Your Ad Budget:
   Use the marketing budget and CAC target to determine the portion of the budget to allocate to advertising.
8. Calculate Return on Ad Spend (ROAS):
   Evaluate the effectiveness of ad spend by dividing the revenue generated from ads by the ad spend.
9. Scale Based on Performance:
   Incrementally increase the ad budget based on successful campaigns that generate a high ROAS, optimizing for continued growth and profitability.