How do I make sure a new website is fast from the start?

The short version

• Write the targets into the brief: LCP 2.5 seconds or less, INP 200 milliseconds or less, CLS 0.1 or less.
• Keep the top of the page light: one well-sized image, not a slider or a video.
• Every plugin, font and outside script has a cost. Choose them on purpose.
• Pick hosting that suits the platform, with caching.
• Test on a real phone on mobile data before launch, not just on office wifi.

What targets should I set?

Google’s web.dev team publishes the Core Web Vitals, the three measures Google uses for how a page feels:

web.dev says to measure at the 75th percentile of page loads, separately for phones and computers. In plain terms: most of your real visitors should get a good experience, not just you on a fast connection. Our answer on Core Web Vitals explains each one.

Put one line in the brief: “Key pages must meet Google’s Core Web Vitals ‘good’ thresholds on mobile.”

What decisions affect speed most?

At design

• The top of the page. A single, properly sized photo loads far faster than a slider or a background video. It usually communicates better too.
• Fonts. One or two font families, a few weights. Every extra weight is another file.
• Pop-ups and banners that push content down cause layout shift.

At build

• Platform and theme. A lean theme beats a heavy multipurpose one. See choosing a platform and page builder or block editor.
• Plugins and outside scripts. Chat widgets, review feeds, tracking pixels and social embeds each add weight and delay taps. Add only what earns its place. See how many plugins is too many.
• Images. Sized for the space they fill and compressed, in modern formats. See how big images should be.
• Video embedded so it loads only when played. See embedding video without slowing your site.

At hosting

Good hosting answers quickly and caches pages. A WordPress site that brings in business usually belongs on managed WordPress hosting. See how to choose web hosting.

How do I test before launch?

1. Open each key page on a mid-range phone, on mobile data, not wifi.
2. Note how long until you can read the main content and tap the main button.
3. Run Google’s PageSpeed Insights on the staging copy if it’s reachable, or on launch day. Read the advice, but don’t chase a perfect score; see should I worry about a low PageSpeed score.
4. Scroll and tap while it loads. Does anything jump?

After launch, real-visitor data appears in Search Console’s Core Web Vitals report once enough people have visited.

Why does speed matter?

A slow page tests a customer’s patience, especially on a phone, and makes a business look careless. Speed is also easier to build in than to add later. Once a heavy theme, slider and a dozen plugins are in place, removing them is a redesign.

What are the common mistakes?

• Testing only on the office computer. Your customers are on phones.
• Hero videos and sliders at the top of every page.
• Uploading photos straight from a camera at full size.
• Adding every widget a vendor offers.
• Treating the PageSpeed score as the goal. Real-visitor data matters more.

What if the new site is slow at launch?

Start with the biggest item at the top of the page, then plugins and scripts, then hosting. Our article on what to fix first on phones gives the order.

How much does it cost, and how long does it take?

Built in from the start, speed costs little: it’s mostly choices. Fixing a slow finished site costs more. Testing key pages takes about an hour.

How does E-3 handle this?

E-3 builds on WordPress or as static sites, and runs a speed program for existing sites. Speed fixes, like redesigns, are tested on a staging copy first. “Why is my website slow?” is a question we’ve answered about 50 times in our records.

Related questions

• What are Core Web Vitals?
• WordPress, Shopify or a website builder?
• What goes on a launch checklist?
• Why is my website slow?
• Back to the complete guide to planning a website

Sources

1. Web Vitals (web.dev)