Which KPIs to Use to Measure Your Marketing Agency's Results: The Complete Guide

TL;DR — Article Summary
Measuring the results of a marketing agency requires a structured system of KPIs divided into 4 categories: Acquisition (CPA, ROAS, cost per lead), Engagement (CTR, email open rate, social engagement), Revenue (LTV/CAC, conversion rate, ROI) and Brand (NPS, share of voice, branded search). According to the Gartner CMO Spend Survey 2025, marketing budgets are flat at 7.7% of company revenue and 59% of CMOs consider them insufficient: every euro invested must be tracked. In this guide you will find formulas, updated benchmarks and templates for building a complete performance dashboard.

Why Measuring Agency Results Has Become Essential

The relationship between a company and its marketing agency is built on a fundamental principle: results must be measurable. According to the HubSpot State of Marketing 2025 report, 83% of marketers cite proving ROI as their primary challenge. Yet fewer than half (47%) have a clear framework for evaluating return on investment.

The Gartner CMO Spend Survey 2025 revealed that marketing budgets have remained steady at 7.7% of total revenue, with digital channels absorbing 61.1% of total spend. In a resource-constrained environment, the ability to measure and optimize becomes a crucial competitive advantage: 41% of CMOs surveyed ranked “data, analytics and measurement” among their top 5 productivity-boosting actions.

This guide provides all the tools you need to build a complete measurement system: formulas, industry benchmarks updated to 2025 and operational templates.

1. Acquisition KPIs: How Much Does It Cost to Generate Results

Acquisition KPIs measure the economic efficiency of campaigns in bringing in new customers or qualified leads. These are the first metrics every company should request from its agency.

1.1 ROAS (Return on Ad Spend)

ROAS is the ratio of advertising-generated revenue to advertising cost. It is the most direct KPI for assessing the effectiveness of paid campaigns.

Formula: ROAS = Advertising Revenue / Advertising Cost

According to Triple Whale data, the average Google Ads ROAS in 2025 dropped by 10.03%, settling at 3.68. On Meta (Facebook/Instagram) the average ROAS rose to 2.79. Search campaigns remain the highest-performing at 5.17:1, while Performance Max sits at 2.57:1.

Source: Triple Whale Google Ads Benchmarks, Triple Whale Facebook Ads Benchmarks

1.2 CPA (Cost Per Acquisition)

CPA indicates how much it costs to acquire a single customer or lead. It complements ROAS by measuring unit cost rather than overall return.

Formula: CPA = Total Advertising Spend / Number of Conversions

According to Triple Whale, the median Google Ads CPA grew by 12.35% in 2025, reaching $23.74. This increase reflects rising competition: 13 out of 14 sectors analyzed saw year-over-year increases.

CPAs vary enormously by industry. According to Phoenix Strategy Group data:

• Fintech: $1,450 (the highest)
• Insurance: $1,280
• B2B SaaS: $702
• E-commerce: $70
• Arts & Entertainment: $21 (the lowest)

1.3 CPL (Cost Per Lead)

For B2B or service-based companies, CPL is often more relevant than CPA, as it measures the cost of acquiring a qualified contact before final conversion.

Formula: CPL = Marketing Spend / Number of Leads Generated

According to the WebFX PPC Benchmarks 2026 report, the average CPL for PPC campaigns varies significantly by industry, making it essential to establish personalized benchmarks.

2. Engagement KPIs: The Quality of Interaction

Engagement KPIs measure how the audience interacts with the content produced by the agency. Strong engagement signals message relevance, targeting quality and creative capability.

2.1 CTR (Click-Through Rate)

CTR measures the percentage of people who click on an ad, link or search result relative to total views.

Formula: CTR = (Clicks / Impressions) × 100

According to the GrowthSrc study of 200,000 keywords, the organic CTR for position 1 on Google is approximately 27%, position 2 reaches 14% and position 3 gets 10%. The top 3 organic results capture 68.7% of all clicks.

For search advertising, the average CTR in 2025 stands at 6.66%, with the arts and entertainment sector leading at 13.10%.

Important note: according to GrowthSrc, brands are seeing a 30–60% decline in clicks from Google for informational queries, due to AI Overviews. The position 1 CTR has fallen by 32% compared with earlier data.

2.2 Social Media Engagement Rate

The engagement rate measures the level of audience interaction with social content (likes, comments, shares, saves).

Formula: Engagement Rate = (Total Interactions / Followers) × 100

According to data from Social Insider and Rival IQ, the 2025 benchmarks are:

Source: Social Insider Social Media Benchmarks 2025, Rival IQ 2025 Benchmark Report

Important note: Instagram experienced a 24.1% year-over-year decline in engagement rate in the first half of 2025. LinkedIn remains the platform with the best engagement for B2B.

2.3 Email Marketing: Open Rate and Click Rate

Email marketing remains one of the channels with the highest ROI. According to HubSpot, for B2C brands it is the channel with the best return on investment.

The 2025 benchmarks according to MailerLite:

• Average Open Rate: 43.46% (note: inflated by Apple Mail Privacy Protection)
• Average Click Rate: 2.09%
• Average Click-to-Open Rate: 6.81%
• Legal sector (best click rate): 4.90%
• Manufacturing sector: click rate 4.22%

Practical tip: since Apple Mail accounts for 46% of email clients and automatically pre-loads images, click rate and click-to-open rate are more reliable metrics than open rate for assessing actual performance.

3. Revenue KPIs: The Impact on the Bottom Line

These are the KPIs that directly connect agency activity to the company’s financial results. They are the most important for management and investors.

3.1 LTV/CAC Ratio

The ratio between Customer Lifetime Value (LTV) and Customer Acquisition Cost (CAC) is considered the “ultimate KPI” of marketing sustainability. It indicates how many times a customer’s value exceeds the cost of acquiring them.

Formula: LTV/CAC = Customer Lifetime Value / Customer Acquisition Cost

According to First Page Sage and HubSpot:

• Below 1:1 — The company loses money on every customer acquired
• 1:1 – 2:1 — Unsustainable in the long term
• 3:1 — Standard benchmark: every euro of CAC generates 3 euros of LTV
• 4:1 – 5:1 — Excellent business model
• Above 5:1 — Possible under-investment in marketing (you could be growing faster)

According to Genesys Growth, omnichannel customers generate a 30% LTV premium, and companies that excel at personalization see a 40% increase in revenue.

3.2 Conversion Rate

The conversion rate measures the percentage of visitors who complete a desired action (purchase, form submission, quote request).

Formula: CR = (Number of Conversions / Total Visitors) × 100

The 2025 data paints a varied picture. According to First Page Sage and Unbounce:

Sources: First Page Sage Landing Page Benchmarks, Unbounce Conversion Benchmark Report

Note: according to Triple Whale, the average Google Ads conversion rate fell by 9.28% in 2025 — users click more ads but convert less.

3.3 Marketing ROI

ROI is the ultimate KPI that every marketing director and CEO wants to see. It directly connects marketing investment to generated profit.

Formula: ROI = [(Marketing Revenue − Marketing Costs) / Marketing Costs] × 100

To calculate it correctly, all costs must be included: agency fees, media spend, technology tools, internal management costs. An ROI of 500% (5:1) is considered a solid digital marketing benchmark, while an ROI of 200% (2:1) is the acceptable minimum.

4. Brand KPIs: Long-Term Value

Brand KPIs measure the impact of marketing activities on brand perception, awareness and reputation. They are harder to quantify but essential for sustainable growth.

4.1 Net Promoter Score (NPS)

NPS measures the likelihood that customers will recommend the brand to others, on a scale from 0 to 10.

Formula: NPS = % Promoters (9–10) − % Detractors (0–6)

According to Retently, companies with the highest NPS in their sector grow at double the rate of competitors. Reference ranges:

• Below 0: Critical — more detractors than promoters
• 0 – 30: Average
• 30 – 50: Good
• 50 – 70: Excellent
• Above 70: World-class

4.2 Branded Search Volume

The increase in searches containing the brand name is a direct indicator of the awareness generated by marketing campaigns. It can be monitored via Google Trends or Google Search Console.

According to SmartyAds, consistent growth in branded search volume is positively correlated with increasing market share.

4.3 Share of Voice (SOV)

Share of Voice measures a brand’s visibility relative to competitors in a given context (organic search, social, PR, advertising).

Formula: SOV = (Brand Mentions / Total Industry Mentions) × 100

According to the “Share of Voice = Share of Market” principle (validated by ExecViva), over time share of voice tends to align with market share. A brand that invests to have an SOV greater than its market share tends to grow.

5. SEO KPIs: Organic Growth

If the agency manages the SEO strategy, specific KPIs are needed to evaluate organic positioning and unpaid traffic.

5.1 Organic Positioning and Visibility

According to the GrowthSrc study of 200,000 keywords and Backlinko data:

• Position 1 on Google receives 27.6% of all clicks
• Moving from position 2 to position 1 generates 74.5% more clicks
• The top 3 results capture 68.7% of total clicks
• A CTR above 3% in SEO is considered good

Beware of the AI Overviews impact: Google’s AI-generated answers are reducing organic clicks by 30–60% for informational queries. It is critical that the agency monitors not only rankings but also actual CTR and real traffic.

5.2 Organic Traffic and SEO Conversions

According to Zero Gravity Marketing benchmarks, lead-generation websites typically convert between 1% and 3% of organic traffic, with local services achieving higher percentages. It is essential to track not just traffic volume but also quality (bounce rate, time on page, conversions).

6. How to Build the Performance Dashboard

A common mistake is monitoring too many KPIs without a clear hierarchy. Here is a practical framework for organizing the data, inspired by the Gartner CMO Spend Survey 2025 budget breakdown (Paid Media 30.6%, Martech 22.4%, Labor 21.9%, Agencies 20.7%).

6.1 The KPI Pyramid

Organize your KPIs across three levels:

1. Strategic Level (monthly, for the CEO/Board): Overall ROI, LTV/CAC, revenue growth attributable to marketing
2. Tactical Level (weekly, for the Marketing Manager): ROAS by channel, CPA, conversion rate, organic traffic, engagement rate
3. Operational Level (daily, for the agency): CTR, CPC, CPM, email open rate, impressions, keyword rankings

6.2 Recommended Reporting Template

Ask your agency for a structured monthly report that includes:

• Executive Summary — 3–5 main KPIs with trends vs. the previous month
• Performance by Channel — Spend, results and ROAS breakdown for each channel (Google Ads, Meta, SEO, Email, Social)
• Conversion Funnel — Visualization of the full journey: impressions → clicks → leads → customers → revenue
• Benchmark Comparison — Comparison with industry benchmarks for each key KPI
• Insights and Recommendations — Qualitative analysis and proposed actions for the following month
• Budget Tracking — Actual vs. planned spend, with end-of-quarter projection

7. The Best-ROI Channels in 2025

Not all channels deliver the same returns. According to the HubSpot 2025 report:

For B2B brands, the highest-ROI channels are:

1. Website, blog and SEO
2. Paid social media
3. Social media shopping tools

For B2C brands, the highest-ROI channels are:

1. Email marketing
2. Paid social media
3. Content marketing

The content formats with the highest ROI are short-form video (21%), images (19%) and live video (16%). Additionally, 96% of marketers reported that personalized experiences increased sales.

8. Common KPI Measurement Mistakes

Even with the right KPIs, there are pitfalls to avoid:

1. Focusing on vanity metrics: Followers, impressions and likes do not pay the bills. Always ask for the connection to conversions and revenue.
2. Ignoring the attribution model: Last-click does not tell the full story. According to HubSpot, multi-touch models reveal which channels actually generate value.
3. Not contextualizing benchmarks: A €50 CPA can be excellent for a B2B company with a €10,000 LTV and disastrous for an e-commerce site with a €30 average order value.
4. Measuring too infrequently: A quarterly report does not allow for timely optimizations. Operational KPIs should be monitored daily.
5. Forgetting seasonality: Always compare year over year (YoY) and not just month over month (MoM) to avoid distorted conclusions.
6. Overlooking the AI impact: With 92% of marketers saying AI has already impacted their role (HubSpot 2025), benchmarks are changing rapidly. Organic CTR, for example, is declining because of Google’s AI Overviews.

9. Checklist: 10 Essential KPIs to Request From Your Agency

Here are the 10 KPIs every company should require in its agency’s monthly reporting:

1. ROAS for each paid channel (target: ≥ 4:1)
2. CPA / CPL with monthly trend and industry comparison
3. Conversion Rate for the website and landing pages (target: ≥ 3%)
4. Organic traffic with page and keyword breakdown
5. Engagement Rate on social with platform-by-platform comparison
6. Email CTR (not just open rate) segmented by campaign
7. LTV/CAC ratio (target: ≥ 3:1)
8. Overall marketing ROI (target: ≥ 5:1)
9. Branded Search Volume with quarterly trend
10. NPS or equivalent customer satisfaction metric (target: ≥ 30)

Frequently Asked Questions

What is the most important KPI for measuring a marketing agency?

There is no single universal KPI. The most important one depends on your objectives: for direct sales it is ROAS (target ≥ 4:1), for sustainable growth it is the LTV/CAC ratio (target ≥ 3:1), for brand awareness it is Share of Voice. Ideally, combine 3–5 strategic KPIs in an integrated dashboard.

How often should I receive reports from the agency?

Best practice involves three levels: an automated daily report for operational KPIs (spend, CPC, CTR), a weekly summary report for tactical KPIs (ROAS, CPA, conversions), and an in-depth monthly report for strategic KPIs (ROI, LTV/CAC, NPS) with insights and recommendations.

How can I verify whether the benchmarks provided by the agency are realistic?

Cross-check the data against independent sources such as Triple Whale for Google/Meta Ads, Rival IQ for social, MailerLite for email marketing, and First Page Sage for landing pages. Make sure the benchmarks are specific to your industry and geographic market.

ROAS is declining: does that mean the agency is doing a bad job?

Not necessarily. According to Triple Whale, the average Google Ads ROAS fell by 10.03% in 2025 and CPA rose by 12.35% globally. This is a market-wide trend driven by increased competition. What matters is that your company’s ROAS is declining less than the industry average and that the agency is proposing optimization strategies.

How much budget should I allocate to marketing for measurable results?

According to the Gartner CMO Spend Survey 2025, the average is 7.7% of revenue. Of that amount, 30.6% goes to paid media, 22.4% to martech, 21.9% to internal resources and 20.7% to agencies. For Italian SMEs, a budget between 5% and 10% of revenue is a reasonable starting point.

How do I measure the ROI of brand awareness activities?

Brand activities are harder to quantify in terms of direct ROI. Use a combination of: branded search volume (via Google Trends and Search Console), Share of Voice vs. competitors, NPS (periodic surveys), social mentions and direct traffic to the website. Monitor these indicators quarterly to identify trends.

What tools are needed to track all these KPIs?

A basic setup includes: Google Analytics 4 (traffic and conversions), Google Ads / Meta Business Suite (paid performance), Google Search Console (SEO), a CRM like HubSpot or Salesforce (LTV/CAC), an email marketing tool with built-in analytics, and a dashboard platform like Looker Studio or Databox to centralize everything.

Sources and References

• Gartner 2025 CMO Spend Survey — 2025 Marketing budget and allocation
• HubSpot State of Marketing 2025 — Trends, channel ROI, AI impact
• Triple Whale Google Ads Benchmarks 2025 — ROAS, CPA, CTR by industry
• Triple Whale Facebook Ads Benchmarks 2025 — ROAS and Meta metrics
• Triple Whale — What Is a Good ROAS? — ROAS benchmarks by industry
• First Page Sage — Landing Page Conversion Rates 2025
• First Page Sage — LTV to CAC Ratio Benchmark
• GrowthSrc — Google Organic CTR Study 2025 — Organic CTR by position
• Backlinko — Google CTR Statistics
• Social Insider — Social Media Benchmarks 2025
• Rival IQ — 2025 Social Media Industry Benchmark Report
• MailerLite — Email Marketing Benchmarks 2025
• Unbounce — Average Conversion Rates for Landing Pages
• Phoenix Strategy Group — CAC Benchmarks by Industry
• Retently — What is a Good Net Promoter Score? 2025 Benchmark
• Genesys Growth — CLV Growth Statistics 2025
• WebFX — PPC Benchmarks 2026
• SmartyAds — Brand Awareness KPIs 2025