CAC and UX: Where Design Loses Users in the Engagement Funnel

CAC (Customer Acquisition Cost) – how much it costs to attract one paying user. For most businesses, this is one of the most painful expenses.

Marketing spends money on traffic. Sales for leads. And part of the budget quietly leaks elsewhere: users come to the site, see the interface - and leave. Not because the product is bad. Because the design didn't deliver value, broke trust, or created too much friction.

This is the responsibility of the designer in the attraction funnel: not to bring users, but not to lose those brought.

## CAC: What it is and how to count it

** Formula:** CAC = All acquisition costs per period / Number of new customers for the same period

The costs of attraction include: advertising budget, marketing and sales salaries, tools, agency commissions.

** Example:**

• Monthly advertising budget: 500,000 м
• Salaries of the marketing team: 300,000 овой
• New paying customers: 100
• CAC = 800,000 / 100 = 8,000

The key ratio is LTV/CAC. The norm is 3:1 and above. If LTV = 24,000 . and CAC = 8,000 . is a 3:1 ratio, the business is sustainable.

## Where design lives in the attraction funnel

The attraction funnel looks something like this:

Advertising / Organic search
↓
Transition to landing / site
↓
Reading / viewing content
↓
Target action (registration, application, purchase)
↓
Onboarding / First Use
↓
First payment

Marketing controls the first step: showing. Design controls everything else.

If the conversion from go to the site to registration is 2%, and you can make 4%, it halves the CAC without changing the advertising budget.

## Landing: First touch and first losses

Landing is where most users decide to stay or leave. It takes less than 15 seconds on average.

### What Kills Conversion on Landing

**A new generation workflow management platform is not clear to whom, why and why. The user must understand in 3 seconds: what it is, for whom and what is the value.

The working structure of the header is: [What the product does] + [for whom] + [the result]. Manage team projects in one place – without unnecessary meetings.

**The difference between expectation and reality. ** If the ad was “automate reports”, and on the landing page – the general words about “business efficiency” – the user feels the discrepancy and leaves. Message match between advertising and landing is one of the strongest conversion factors.

Slow loading. With a download delay of 1 second, conversions drop by 7% (Akamai data). After 3 seconds, most of the users have already left. This is a technical issue, but the designer influences through: the weight of images, the number of fonts, the complexity of animations.

Too many options. Three CTAs on the screen - the user does not know where to click. One clear next step converts better than “register”, “watch the demo”, “read the cases”, “download the guide”.

No social proof in the right place. Customer reviews and logos work, but only if they are in the right place – near the decision points, not at the bottom of the page.

** There is no answer to the main objection.** “What if it doesn’t fit?”, “What if it’s difficult?”, “What if I can’t cancel?” – if the landing page does not respond to the main fears, some users leave with an unmoved objection.

### The structure of a highly convertible landing

This is not a universal formula, but a working framework:

1. Hero. Clear title + subheading + one CTA. No extra elements in the first screen.

2. Social proof. Logos of known customers or numbers ("use 15,000 commands") Right under the hero - not at the end.

3. **Describe the pain that the product solves. The user must recognize himself.

4. **How does the product solve this problem? Specifically, no abstractions.

5. Key features/advantages. Maximum 3-5. With an emphasis on value, not on technical specifications.

6. Social proof is deep. Cases, quotes, customer results.

7. Response to objections. FAQ or separate block with major fears.

8. CTA. Repeat the main call to action.

## Registration Form: Where “warm” users are lost

The user finished reading the landing page, clicked on "Register" - and here it is before the form. This is a warm, interested user. That's where it hurts to lose.

### Typical errors in registration forms

Too many fields. Each additional field reduces conversion. In the Formstack study, reducing the form from 11 to 4 fields increased conversions by 120%.

Minimum registration: email + password. Everything else is after.

Bad Error Messages. The incorrect format does not help the user. Enter email in name@domain.com format – helps. Errors should be near the field, specific and suggest a solution.

Weak password requirements without explanation. "A minimum of 8 characters, including a number and a special character" - OK. Showing this only after the user has already entered the password is bad. Requirements should be visible when focusing on or before the field.

No autocomplete. Browsers can autofill emails and passwords. If the form blocks this, users are annoyed.

No social login. Log in through Google converts better for most B2C products because it removes password friction. For B2B, it depends on the audience.

Double confirmation email. In 2026, this pattern looks archaic. Verification through single confirmation email is sufficient.

### Shape patterns that work

• One field on the screen (especially on mobile)
• Real-time validation: checking directly at input, not when sending
• Progress indicator if registration is multi-step
• "Back" works without loss of input data
• The submit button clearly shows what’s going to happen: “Create an account,” not just “Next.”

## First screen after registration: activation rate

The user has registered. Now the most important thing is what he sees next.

Most products throw the user onto an empty home screen with navigation and no direction. This is a direct path to zero D1 retention and high CAC (money spent and the user left with nothing).

The first screen should:

• Show a specific first action
• Don't overburden with choice
• Have guided setup or welcome flow elements

First screen Patterns:

• Welcome wizard. Let’s set up your account in 3 minutes. Structured onboarding with progress.
• A template or an example. Instead of an empty canvas, it is a ready-made example to study. This is how Notion works with ready-made templates.
• One CTA. One clear first step, the rest later.

## Landing for different segments

One landing page doesn’t convert the same for everyone. A LinkedIn user with an enterprise query and a user with a free task tracker are different people with different expectations.

What do you do

• Create separate landing pages for different channels or segments (enterprise vs. SMB, individual vs. team)
• Use message match: Landing header should echo what the user clicked on
• Test different value propositions for different segments

## A/B tests to optimize CAC

Intuition in landing design helps less than you want to think. What converts better, you need to check.

What to test for first:

1. Title: The main hypothesis: how value is formulated
2. Basic CTA (button formulation)
3. Social proof: customer logos vs. citations vs. numbers
4. Availability/absence of hero videos
5. Number of fields in the registration form

Test priority: Start with above-the-fold elements (first screen). It has the biggest traffic and the biggest impact on conversion.

Minimum test time: to statistical significance (p < 0.05). Usually a minimum of 1-2 weeks for sufficient data.

## How to count the contribution of design to reducing CAC

It is important to be able to show - as a justification for work on the landing or form.

** Example of calculation:**

Current status:

• Transitions to landing per month: 10 000
• Conversion rate (transition → registration): 3%
• New users per month: 300
• Advertising budget: 300,000 м
• CAC = 300,000 / 300 = 1,000

After the landing redesign:

• Transitions: same 10,000
• Conversion rate: 5%
• New users: 500
• Advertising budget: same 300,000 м
• CAC = 300,000 / 500 = 600

A 40% reduction in CAC without changing the advertising budget is a specific design contribution.

## Typical points of loss of users in the funnel: checklist

Landing:*

• Title clear from the first 3 seconds (test on someone who doesn’t know the product)
• Message match: Landing matches what the user clicked on
• One main CTA on the first screen
• Social proof is visible on the first two screens
• The main objection ("What if it doesn't fit?") is clearly worked out
• Download speed: Lighthouse score ≥ 90

** Registration form:**

• Minimum number of fields (email + password to start)
• Mistakes are specific and stand next to the field
• Real-time validation works
• Social login available (if B2C audience)
• The submit button describes what’s going on: “Create an account,” not “Next.”

First screen after registration:

• The user sees one specific next step, not an empty screen with navigation
• Guided setup or welcome flow
• The first action is possible in 2-3 minutes

## Why users do not believe the landing: working with trust

The conversion of a landing page depends not only on how clear and convincing the offer is – but also on how much the user trusts what is written.

There's a lot of promise online. The user comes with skepticism. The task of landing is not only to explain the value, but also to remove the barrier of distrust.

### Elements of trust and where to place them

Logos of well-known customers. Work best in the first or second screen – where the user still decides to stay or not. “Yandex, Sber, Tinkoff trust us” is a signal that the product has been tested by serious players.

** Specific numbers instead of adjectives.** "More than 10,000 commands" instead of "thousand commands." Saves an average of 4 hours a week instead of saving time. Specifics = trust.

“Maria Ivanova, Project Manager, Alfa-Bank” with a photo is a completely different level of trust than “User X, Financial Company”.

Transparency in pricing. Hidden commissions and unexpected terms are the biggest killer of trust. “No hidden payments, one-click cancellations” are not just words, they are insurance against the barrier of distrust.

** Data security. ** For products that work with user data – SSL certificate, mention of data protection, compliance with GDPR or 152-FZ. This is especially important for B2B.

** Guarantees.** “30 days free, no card is needed” or “We will return the money if it does not fit” – remove the main fear: “I will spend the money and it will be the wrong one.”.

### Anti-trust patterns

Stock photos instead of real ones. Users have learned to distinguish between stock images. They reduce trust, not increase it.

**Excellent product! 10/10 without name, company and specifics - does not work. More suspicious.

Exaggerated promises. “Enhance your productivity by a factor of 10” is perceived as a marketing bullshit and reduces trust in everything else on the page.

Intrusive pop-ups. "Only for you 50% off the next 10 minutes" - the user sees this and thinks "this is not a real discount." The urgency must be real, otherwise it is a manipulation pattern.

## Mobile-first: where landing pages lose mobile users

In 2026, most traffic comes from mobile devices. But most landing pages are still optimized primarily for desktop, and mobile is “somehow afterwards.”.

It's an expensive mistake.

### Specificity of mobile behavior

The thumb determines the design. On the mobile, the user holds the phone with one hand. The reach of the thumb is the lower third of the screen. CTA buttons should be there, not in the middle or top.

No pointing to the cursor. Hover effects do not work. If the hint appears on the desktop when hovering, it does not exist on the mobile.

Slow internet. Mobile connections are unstable. Landing weighing 5 MB with a dozen images on LTE loads acceptable, and 3G — not. Optimizing for the slow Internet is not an optional task.

Short attention. On mobile, the user often looks at the phone between business — in transport, in line. The key message should be read in 5-8 seconds.

### Typical problems of mobile landings

• Small text that cannot be read without zoom (<16px)
• The buttons are too small to press with your finger (<44×44px)
• Form with fields that are difficult to fill out on a virtual keyboard
• Horizontal scrolling (tables, long lines of code)
• Pop-up windows that cannot be closed on a small screen
• Autoplay video with sound

## Funnel attraction for B2B: features

B2B products have a fundamentally different funnel of attraction. There is not one user making a decision - there is a process of approval, demo, tender.

### Key differences of the B2B funnel

Many points of contact. Users see a product at a conference, then Google, then go to the site, then ask a colleague to look, then order a demo. Each point is a potential gap.

** Different roles make the decision.** Champion (the one who promotes the product inside), Decision Maker (the one who signs), IT (the one who agrees security). Everyone needs their own information.

Long sales cycle. Between the first visit to the site and the first payment can take 3-6 months. Content should keep you interested all the time.

### What it means for B2B Landing Design

Give different inputs for different roles. For development teams, for project managers, for IT managers, everyone finds their own.

ROI calculator. The B2B buyer must justify the purchase before management. The built-in ROI calculator helps to do this. Enter the size of the team – calculate how many hours per week you will save.

** Cases from your industry.** How Company X from [the realm] increased [the metric] by [the number]% is what a B2B buyer reads. Not abstract testimonials, but specific cases.

**Demo or trial without barriers. For B2B, “trying” is more important than ever. If a trial requires a corporate email and a call from a salesperson, most potential customers will go to competitors with a self-serve trial.

## What Happens to CAC as Product Growth

As a product grows, CAC tends to grow – and a designer needs to understand why.

At the very beginning: the first customers come by word of mouth, they are loyal and cheap. CAC's low.

When scaling: the advertising market is saturated, the best audiences are already covered, you need to pay more for each next display. CAC's growing.

What helps keep CAC under control when growing:

Organic growth and SEO. Content that ranks in search is traffic without fixed costs. Once created an article - it leads users for years. The design of landing pages for SEO traffic is critical.

Product-led growth. Users engage other users through product. Invitations to team products, results sharing, public pages are viral mechanics with CAC close to zero. These are all design solutions.

Viral coefficient. If each new user invites an average of 0.3 other users, 30% of the growth comes without marketing costs. Invitation design, sharing mechanic and “made with X” branding directly influence this ratio.

Brand awareness. When a brand is known, the cost of clicking in advertising is lower, conversion from landing is higher. The design of the product you want to show others works on brand awareness.

## AI and CAC: how to find and eliminate losses in the funnel of attraction

AI helps in three ways: Analyze the landing text, calculate the financial effect of UX changes, and generate hypotheses for A/B tests.

### Prompt: Landing audit for conversion

You can upload a screenshot or describe the structure of the landing:

Here is [screenshot/structure description] of our landing page.

Product: [What it does, for whom]
Target action: [Registration / application / purchase]
Current conversion rate: [%]
Main traffic source: [context/SEO/social media/etc]

Conduct a landing page audit in terms of conversion:
1. How clear is the title (rule of 5 seconds: is it clear in 5 seconds who it is and why)?
2. Is there a message match with a likely source of traffic?
3. How convincing is the social proof and is it correctly positioned?
4. How clear and convincing is the core CTA?
5. Have the main objections been worked out?

For each item: assessment and specific recommendation.

### Prompt: generate hypotheses for A/B tests on the landing

Landing: [description or screenshot]
Current conversion rate: [%]
Benchmark for our niche: [%] (if you know)
Data from analytics: [scroll depth, heatmap observations, if available]

Generate 10 hypotheses for A/B tests. For each:
- What's changing (element)
- What to change (specific version B)
- Why It Should Help (Conversion Impact Mechanics)
- Expected effect size: large/medium/small

Sort by impact potential × ease of implementation.

### Prompt: calculate the financial effect of improving conversion

Current data:
– Landing traffic per month: [number]
- Current conversion rate (visitor → registration): [%]
- Conversion from registration to payer: [%]
- ARPU: [sum]  

Calculate:
1. Current number of payers per month
2. Current CAC if advertising budget: [amount]

Then model three scenarios to improve conversion rate landing:
- Pessimistic: +0.5%
- Basic: +1%
- Optimistic: +2%

For each scenario: new CAC, decrease in % and in rubles, additional income for the year.

### Prompt: Improve CTA text and title

Here is the current title of our landing: "[insert]"
Current CTA: "[insert]"

Product: [Description]
Audience: [who is the target user]
The main pain of the audience: [what bothers them]

Offer 5 header options and 5 CTA options.

Each option should be clear in 3 seconds and answer the question “why do I need this?”
For CTAs, everyone should describe the action and the result, not just the command ("Start free" not "Try")