For managing partners in law firms, accountancy practices and consultancies, marketing can feel like an expensive black box. You know you’re investing in it, but how do you measure success? This is where Key Performance Indicators (KPIs) come in. By tracking the right KPIs, you can see where your marketing efforts are paying off—and where you need to make changes to drive better ROI.

Here are six essential KPIs for professional services marketing, what they mean, how to measure them, and what to do if they’re not performing well.

1. New client acquisition cost

What it means

This KPI tells you how much it costs, on average, to bring in a new client. It includes marketing spend, sales time, and any other resources used to convert a prospect into a paying client.

How to measure it

Use this formula:
Total marketing and sales costs ÷ Number of new clients acquired

What to do if it’s too high

• Refine your target audience. If you’re marketing to too broad an audience, your cost per acquisition will be high. Tighten your messaging to reach the right prospects.
• Optimise your website and content. Ensure your site clearly explains your services and includes strong calls to action (CTAs). A well-structured website reduces the time and effort needed to convert visitors into clients.
• Leverage referrals. Encourage existing clients to refer new business, these leads are often lower cost and more likely to convert.

2. Client retention rates

What it means

Retaining clients is just as important as winning new ones. This KPI measures the percentage of clients who continue working with your firm over a given period.

How to measure it

Use this formula:
(Number of clients at the end of a period – New clients acquired) ÷ Number of clients at the start of the period × 100

What to do if it’s low

• Improve client experience. Regular check-ins, personalised service, and proactive support keep clients engaged.
• Introduce value-added services. Can you offer additional services that complement your existing ones? Expanding your support can make clients more likely to stay.
• Create client education initiatives. Webinars, newsletters, and legal updates help clients see ongoing value in your firm.

3. Revenue growth from existing clients

What it means

This KPI tracks how much revenue is generated from clients already on your books. Ideally, you want to see steady growth from repeat business and additional services.

How to measure it

Compare revenue from existing clients year-over-year or quarter-over-quarter.

What to do if growth is slow

• Develop a cross-selling strategy. Identify complementary services and educate clients on how you can support them further.
• Enhance client engagement. Regular strategic reviews with clients can uncover new legal needs before they arise.
• Implement a loyalty programme. Preferred rates or exclusive benefits for long-term clients can incentivise them to stay and spend more.

4. Market share in target sectors

What it means

This measures your firm’s position within the specific industries or practice areas you serve. If your goal is to be the go-to law firm for tech startups, for example, you should be tracking how much of that market you’ve secured.

How to measure it

Compare your firm’s revenue or client base within a sector to the total market size.

What to do if it’s lagging

• Refine your positioning. Make sure your firm is clearly differentiated in your target market.
• Strengthen industry partnerships. Speaking at industry events, joining trade associations, and contributing to sector-specific publications can boost your reputation.
• Invest in thought leadership. High-quality, sector-specific content can establish your firm as an expert and attract more clients.

5. Brand awareness metrics

What it means

Brand awareness measures how well your firm is recognised in your target market. Strong brand awareness makes client acquisition easier.

How to measure it

• Social media engagement
• Website traffic trends
• Brand mentions in the press and industry publications
• Direct traffic (people typing your firm’s name into search engines)

What to do if awareness is low

• Increase PR efforts. Contribute to professional journals, provide expert commentary in the media, and issue press releases.
• Strengthen LinkedIn presence. Thought leadership posts from senior partners can build visibility and credibility.
• Run targeted advertising. Google Ads and LinkedIn Ads can put your firm in front of the right audience.

6. Website traffic to lead conversion rates

What it means

Your website should be a key source of new business. This KPI measures what percentage of website visitors take a desired action (e.g., filling out a contact form or booking a consultation).

How to measure this KPI

Use this formula:
(Number of leads generated ÷ Total website visitors) × 100

What to do if conversions are low

• Improve website usability. Ensure your site is mobile-friendly, loads quickly, and is easy to navigate.
• Enhance calls to action. Clear, compelling CTAs (e.g., “Book a Consultation” or “Download Our Legal Guide”) can boost conversions.
• Use lead magnets. Free resources like legal checklists or whitepapers encourage visitors to share their details.

Final thoughts

Tracking these KPIs will give you a clearer picture of your firm’s marketing effectiveness. But don’t forget to track the KPIs that are most relevant to you and not to get too bogged down by data, If your numbers aren’t where you want them to be, use the tips above to refine your strategy and improve your return on investment.

Need help? If you would like help with your marketing, then bringing on a marketing consultant with a fresh pair of eyes can make all the difference. I work with B2B businesses and professional service firms in London, Kent, UK, and Europe, as well as specialising as a legal marketing consultant. Please get in touch or book a free 30-minute consultation.

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