Website speed checklist: twenty checks before you spend

Key takeaways

This website speed checklist covers twenty checks in five groups: the first screen, responsiveness, stability, the wider journey and upkeep. Work through it on a phone over mobile data before paying for any speed work. Most small business sites fail the same six or seven checks, and several of those can be fixed without a developer. The list is ordered so that the cheapest, highest-impact items come first.

• Twenty checks in five groups, done on a phone in about an hour.
• First screen checks come first, because they affect every visitor.
• Several fixes need no developer: images, unused plugins and old tags.
• Re-run the list every quarter and after any redesign.

How should you use this checklist?

Use a mid-range phone, switch off Wi-Fi and open a private browsing window. Pick the three pages that receive most first visits. Mark each check pass, fail or not sure, then fix failures in the order listed. Have PageSpeed Insights open on the mobile tab for the checks that need a measurement.

• How website speed affects customer experience and conversions
• How to test website speed the way customers feel it

Checks 1 to 5: is the first screen fast?

• 1. The headline is readable within about 2.5 seconds.
• 2. The main image is sized for the screen and in a modern format.
• 3. There is no slider or background video on mobile.
• 4. The main button and phone number appear as text, not inside an image.
• 5. The server responds within about 0.8 seconds.

• Optimise website images for speed and search
• Time to first byte: is your server the slow part?

Checks 6 to 9: does the page respond?

• 6. The menu opens on the first tap, as soon as it appears.
• 7. Every button shows a pressed state.
• 8. Chat, pop-ups and reviews load after the main content.
• 9. Interaction to Next Paint is within 200 milliseconds in field data.

• Website slow to respond to taps and clicks? Causes and fixes
• Third-party scripts: the hidden reason your site is slow

Checks 10 to 13: does the page stay still?

• 10. Nothing moves after the visitor starts reading.
• 11. Images and embeds have their space reserved.
• 12. The cookie banner is an overlay, not pushed in at the top.
• 13. Cumulative Layout Shift is below 0.1 in field data.

• Why your website jumps around while it loads
• Is your cookie banner slowing your website down?

Checks 14 to 17: is the whole journey fast?

• 14. The second and third pages load faster than the first.
• 15. The back button returns to the previous page at once.
• 16. The enquiry form confirms within a second of Send.
• 17. Booking, search or checkout steps show progress while they work.

• Speed between pages: why the second click matters too
• Slow enquiry forms: the wait after a visitor clicks Send
• Slow booking widgets: where appointment bookings are lost
• Checkout speed: how slow payment steps lose orders

Checks 18 to 20: will it stay fast?

• 18. Page caching is on for public pages.
• 19. There is a current list of plugins, tags and third-party scripts, each with an owner.
• 20. Someone checks key pages monthly and after every change.

• Website caching explained for business owners
• Performance budgets: stop your website slowing down again
• Website speed monitoring: catch slowdowns before customers

What does the checklist not cover?

The checklist tells you what is slow, not always why, and it rates speed alone. A site can pass all twenty checks and still fail to win enquiries because the offer is unclear or the proof is thin. It also relies on one phone on one day, so confirm borderline results with field data.

Use it to build a short, ordered fix list. If more than half the checks fail, or the failures point to the theme or platform, get a diagnosis before spending.

• High-converting website checklist
• Website audit checklist for small businesses

What does this look like in practice?

A pattern we see when owners run this list for the first time: the first screen checks mostly pass, because someone has optimised the homepage, and the journey checks fail. The form takes several seconds, the back button reloads the page and nobody has looked at the tag list in two years.

Those failures are usually cheaper to fix than the ones people expect to find. Across client work at Global Bridge Labs (GBL), we have seen a 2.4x enquiry rate from conversion changes like these.

• See client work
• Website Design & Development for UK businesses

Next step

Twenty checks and an hour will tell you whether you have a speed problem and roughly where. If you would like the list run for you, with the fixes costed, we can do that.

• The website speed scorecard: score your site in an hour
• A 90-day plan to make your website faster
• Website speed optimisation costs in the UK