Data

What a tenth of a second is worth to a booking website

Site speed is treated as a technical hygiene issue. In travel it is one of the largest commercial levers available.

Published 2026-08-18

The number

Research commissioned by Google and conducted by 55 and Deloitte, covering more than 30 million user sessions across 37 European and American brand sites, found that a 0.1 second improvement in mobile site speed produced a 10% increase in booking rates on travel sites, alongside a 2.2% rise in checkout completion⁵.

A tenth of a second. Not a second, not a redesign, not a new brand. A tenth of a second, worth ten per cent on the metric that pays your mortgage.

Why it hits self-catering harder

Sixty-one per cent of online accommodation bookings now happen on mobile². A great deal of holiday research happens on patchy connections, on older phones, in the evening.

Meanwhile the typical self-catering site is heavy in precisely the ways that hurt: large uncompressed photography, an embedded booking widget, a map library, a review widget, a chat widget and a cookie banner, all competing for the same first two seconds.

Where the weight actually is

In our experience, in this order: images, third-party embeds, fonts, and everything else. Images are usually more than half the payload and almost always the easiest win.

Modern formats, correct dimensions, explicit width and height to prevent layout shift, and genuine lazy loading below the fold will typically halve the weight of a property page without touching the design.

Treating speed as a design decision

The mistake is scheduling performance work as an optimisation phase after launch. By then the decisions that determine speed — how many embeds, which map, how the gallery works, whether the site is statically rendered — have already been made.

Set a budget before design begins: a target Largest Contentful Paint, a maximum page weight, a maximum number of third-party scripts. Then design within it. It is a constraint like any other, and constraints tend to improve design rather than damage it.

What to measure

Largest Contentful Paint, Cumulative Layout Shift and Interaction to Next Paint, on a property page, on a mid-range Android over 4G. Not on your laptop on office wifi.

Then measure booking rate by device. If the mobile booking rate is a fraction of desktop, speed is usually a large part of the reason — and unlike most conversion problems, it is entirely fixable with engineering rather than guesswork.