UI/UX Design Principles That Boost Conversions

Website UI/UX design that improves conversions and user experience

Contents

UI/UX design principles for business websites that have been shown to lift conversions: (1) Clarity: users know what to do within 5 seconds; (2) Visual hierarchy: the most important elements stand out the most; (3) Consistency: patterns repeat across pages; (4) Mobile-first: design for smartphones first, then desktop; and (5) Accessibility: sufficient colour contrast and complete ARIA labels.

UI (User Interface) and UX (User Experience) are often treated as the same thing, but they are different: UI focuses on appearance (colour, layout, typography), while UX focuses on the user's journey (flow, ease of use, satisfaction). This article covers 10 principles to apply when you build a business website.

Key points in this article

UI is the visual layer and UX is the user's journey (related, but different)
The 5-second test: users should understand the website's purpose within 5 seconds
Visual hierarchy: the most important element is the biggest, the highest-contrast and the nearest the top
Mobile-first is essential (60-70% of traffic comes from mobile)
Accessibility: WCAG AA as a minimum, for inclusivity and for SEO
One primary CTA per page, not 3-4 at once
Load time under 3 seconds and INP under 200ms for the best UX

1. Clarity: users understand your purpose within 5 seconds

The 5-second test: show your home page to a stranger for 5 seconds, then ask: “What is this website about?” If they are confused, your clarity has failed.

How to apply the clarity principle:

A clear H1 headline: state WHAT you offer (product or service) and FOR WHOM (audience)
A supporting subheadline: state the main BENEFIT in one sentence
A relevant hero image: a picture that represents your value proposition straight away
One visible primary CTA: a dominant “Buy/Sign up/Contact us” button

An example of CLEAR hero copy: “Company Profile Website Development for Manufacturing Companies”. A POOR example: “Welcome to our digital solutions” (too generic).

2. Visual hierarchy: guide the user's eye by priority

Visual hierarchy directs the user's eye to the most important element first, then down to the details. The main tools are:

Size: larger elements get more attention (headings larger than body text)
Colour: high-contrast colours (an orange button on a blue background) draw the eye
Position: the top and centre of the page carry high priority
Whitespace: surround important elements with empty space
Typography: bold or italic type for emphasis

Test it: scan your page while squinting. The elements you can still make out are high in the hierarchy. If your CTA button disappears from view, the hierarchy has failed.

3. Consistency: repeat patterns across pages

Users learn the patterns on the first page, then expect the same patterns on other pages. Inconsistency creates friction.

Elements that must stay consistent:

Navigation: the same position and menu order on every page
Colour palette: primary, secondary and accent colours (5-7 brand colours at most)
Typography: consistent H1/H2/H3 and body text sizes and line heights
Button style: the primary CTA in the same colour across the whole website
Iconography: one icon style (outline or filled, never mixed)
Spacing: a consistent margin and padding pattern

Use a design system (a Figma library, or Storybook for developers) to keep your team consistent. For inspiration, see also our comparison of the best WordPress page builders.

4. Mobile-first design is essential (60-70% of traffic is mobile)

Design for mobile first, then scale up to desktop. Not the other way round, because the constraints of mobile (a small screen, finger taps, slow connections) force you to focus on the essentials.

Mobile-first checklist:

Touch targets of at least 44x44px: the average fingertip is 16-20mm wide
Body text of at least 16px: anything smaller and users need to zoom
A hamburger menu for long navigation
A sticky CTA: the primary button stays visible while users scroll
Large form inputs with the right keyboard type (email fields bring up the email keyboard, phone fields the number pad)
Responsive images and lazy loading to save data

Learn more in our article on mobile-first responsive website design.

5. Accessibility: WCAG AA as a minimum

Accessibility is not optional. Some of your audience has a disability (visual, motor or cognitive). On top of that, many accessibility practices, such as alt text and a tidy heading structure, also help your SEO.

Basic WCAG AA checklist:

Colour contrast between text and background of at least 4.5:1 (check it at webaim.org/resources/contrastchecker)
Descriptive alt text for every image
Keyboard navigation: every action can be reached without a mouse (Tab and Enter)
ARIA labels for non-text elements (icons, modals, dropdowns)
Clear form labels (do not rely on placeholders alone)
Descriptive error messages, shown with an icon as well as colour
A visible focus indicator during tab navigation

Test it with the Lighthouse Accessibility audit in Chrome DevTools and aim for a score above 90.

6. One primary CTA per page, not 3-4 at once

The most common UX mistake is having too many CTAs that are all equally dominant. Users cannot decide which one to click, so they click none of them. This is known as “decision paralysis”.

Rule of thumb:

1 PRIMARY CTA: the most visually dominant (contrasting colour, large)
1-2 SECONDARY CTAs: outline buttons or text links, with less visual weight
Tertiary actions: ordinary links in the footer or sidebar

Example CTA hierarchy for a services landing page:

PRIMARY: “Book a Free Consultation Now” (large orange button)
SECONDARY: “View Portfolio” (outline button)
TERTIARY: “Learn about our process” (text link to the About page)

7. Load time under 3 seconds (UX and SEO)

53% of mobile users abandon a website that takes more than 3 seconds to load. In addition, Core Web Vitals are a Google ranking factor.

Core Web Vitals targets for the best UX:

LCP (Largest Contentful Paint) under 2.5 seconds: the hero image or text appears quickly
INP (Interaction to Next Paint) under 200ms: a fast response when users click
CLS (Cumulative Layout Shift) under 0.1: the layout does not jump around while it loads

See the optimisation details in Core Web Vitals 2026 and how to speed up WordPress.

8. Whitespace is a premium design element

Whitespace (empty space) is far from wasted space; it is one of the most important design elements. It gives elements “room to breathe”, improves focus and feels premium.

Applying whitespace:

Generous padding around the primary CTA button (60-80px)
A line height of 1.5-1.7 for body text, which makes it easier to read
Margins between sections of at least 60px (desktop) and 40px (mobile)
A container max-width of 1200-1400px, so content does not stretch full width on large screens

Compare Apple.com (generous whitespace, feels premium) with a local marketplace (crowded, feels low-budget). Whitespace shapes perceived value.

9. Colour psychology for conversions

Colour influences users' decisions unconsciously. Choose your brand and CTA colours to suit the psychology of your industry:

Colour	Associations	Suited to
Blue	Trust, professionalism, stability	Finance, corporate, B2B SaaS
Green	Growth, nature, success	Healthtech, eco, finance
Orange	Energy, urgency, friendliness	CTA buttons, e-commerce, F&B
Red	Urgency, passion, action	Sale promotions, alerts, sport
Black	Premium, luxury, elegance	Luxury fashion, premium brands

10. Test and iterate (UX is an ongoing process)

Good UX comes from iteration: test, learn and keep improving. Useful tools:

Hotjar / Microsoft Clarity: heatmaps and session recordings (free basic plans)
VWO: A/B testing to validate changes (Google Optimize was shut down in September 2023)
Google Analytics 4: funnel analysis and finding drop-off points (see our GA4 guide for beginners)
Manual user testing: 5 users try your website while thinking aloud

Iterate every 4-8 weeks based on the data. A UX that stands still will fall behind the competition.

References

Frequently asked questions

What is the difference between a UI designer and a UX designer?

A UI designer focuses on the visual side: colour, typography, layout, icons and button styles. Their output is a mockup in Figma or Sketch, ready to hand over to developers. A UX designer focuses on the user journey: research, user flows, wireframes, prototypes and usability testing. Their output is a research report, wireframes and interaction design. In practice, at small businesses (UMKM) in Indonesia, one person often handles both roles (the "UI/UX Designer"). For large projects, it is better to separate them: the UI designer is strong visually, while the UX designer understands the business and user behaviour.

Do I need to hire a UI/UX designer for my business website?

It depends on the scale. For a simple company profile website, you do not: use an Elementor or Divi template designed by professionals and customise the colours and content. For a landing page with demanding conversion targets, it is worth hiring a freelance UI/UX designer (Rp 5-15 million) to optimise the funnel. For SaaS or web applications, you need an in-house UI/UX designer or an agency, because the complexity calls for in-depth research. If you are a beginner doing it yourself, use a free UI kit (Figma Community) and follow the 10 principles in this article.

How much does a freelance UI/UX designer cost in Indonesia?

Typical rates: Junior (1-3 years): Rp 100-300 thousand per screen or Rp 3-8 million per landing page project. Mid-level (3-5 years): Rp 300 thousand-1 million per screen or Rp 10-25 million for a complete website project. Senior (5+ years): Rp 1-5 million per screen or Rp 30-100 million for a full SaaS design system. Platforms for hiring include Sribu, 99designs, Fastwork and Upwork. Make sure the designer's portfolio matches your type of business.

Do animations and parallax effects help UX or get in the way?

They help when they are subtle and purposeful: micro-animations on button hover (to give feedback), smooth scrolling between sections and fade-ins as elements enter the viewport. They get in the way when overdone: slow full-page parallax, animations that block reading and autoplay video with sound. The rule is that animation should support the user's task and never distract from it. Test on mobile, and if an animation makes the site lag on a budget phone, remove it. Performance comes before aesthetics.

How can I test whether my website's UX is good or bad?

Four practical methods: (1) The 5-second test: show the site to 5 strangers for 5 seconds, then ask what it is for. (2) Usability testing: ask 5 users to complete 1 specific task (for example "find the pricing packages and click order") and watch where they get stuck. (3) Heatmaps with Hotjar or Clarity: see where users click and what they ignore. (4) Conversion rate analytics: track bounce rate per page and funnel drop-off in GA4. Together, these 4 methods give you a comprehensive UX audit.

Which UX principles do Indonesian business websites break most often?

The top 5 UX violations on Indonesian small business websites: (1) Aggressive pop-ups on the first visit (email capture or discount promos) that block the content. (2) Lots of CTAs that are all equally dominant ("Sign Up Now", "Promo", "Consultation", "Live Chat", all big and orange). (3) Vague hero text ("Your Business Solution") with no clear value proposition. (4) Stock photos of Western models that do not resonate with an Indonesian audience. (5) A mobile site that is just the desktop layout squeezed down, with small fonts and buttons that are hard to tap. Fixing these five is a good starting point before you test other changes.

Is dark mode worth it for a business website?

It is worth it if your audience is tech-savvy and often uses websites at night. It suits SaaS dashboards, developer tools, content platforms (Medium, Dev.to) and gaming communities. It is unnecessary for general e-commerce, company profiles and service landing pages. To implement it: (1) Detect the browser's prefers-color-scheme setting. (2) Add a manual toggle in the header. (3) Maintain WCAG contrast in both modes. It adds around 30% to design time. If your core audience does not need it, skip it for now and focus on getting the basic principles right first.

Topics:AccessibilityConversion DesignUI/UX DesignUser ExperienceUX PrinciplesWeb Design

UI/UX Design Principles That Lift Conversions and User Experience