Does a Faster Store Actually Make You Money?
Everyone quotes the load-time conversion stats. Almost nobody measures what speed is worth on their own store.
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By Joris van Huët, Founder & CEOPublished 2 min read
The Stat Everyone Quotes
Slow storefronts do lose sales, but the famous load-time statistics describe other people's stores, and the only number that should move your roadmap is the lift you can measure on your own. Borrowed benchmarks are a starting hypothesis, not your P&L.
You have seen the figures: a one-second delay costing conversions, a few seconds erasing most of a page's revenue. Directionally true and genuinely motivating. The mistake is treating an industry average as your specific bill.
Correlation Wears a Convincing Costume
Slow sites are often slow for reasons that independently hurt sales: a pile of third-party marketing tags, heavy popups, a bloated theme. Speed correlates with revenue partly because the things that slow a page down are also the things that annoy buyers. Strip out the tags and you may capture a lift the stopwatch alone would have miscredited: the same correlation versus causation trap that haunts channel reporting.
Test Your Own Speed
You do not have to guess. Ship a performance fix to a random half of your traffic, hold the rest on the old build, and read the incremental difference in conversion rate and revenue per session. That is your number, not a conference slide's. And when you rank where to spend next, a causal attribution read tells you whether another 200 milliseconds beats another creative test.
Fast is good. Knowing what fast is worth is better.
Frequently asked questions
Do faster websites really convert better?
On average, yes: but industry load-time statistics describe other stores, not yours. Part of the effect also comes from what makes pages slow, like heavy tags and popups, which independently hurt conversion. Measure your own store to get a real number.How do I measure what site speed is worth on my store?
Ship the performance fix to a random half of traffic, hold the rest on the old build, and compare conversion and revenue per session. The difference is the incremental value of speed for your specific store.
Go deeper: Causal attribution, explained.
Sixty-second versions of these ideas: Causality Engine on YouTube Shorts.
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Terms in this article
- AttributionAttribution identifies user actions that contribute to a desired outcome and assigns value to each. It reveals which marketing touchpoints drive conversions.
- Causal AttributionCausal Attribution uses causal inference to determine which marketing touchpoints genuinely cause conversions, not just correlate with them.
- CausationCausation is the relationship where a change in one variable directly causes a change in another.
- ConversionConversion is a specific, desired action a user takes in response to a marketing message, such as a purchase or a sign-up.
- Conversion rateConversion Rate is the percentage of website visitors who complete a desired action out of the total number of visitors.
- CorrelationCorrelation is a statistical measure showing a relationship between variables; it does not imply causation.
- IncrementalityIncrementality is the part of an outcome, such as orders or revenue, that a marketing activity caused: the extra results compared with what would have happened without it. It is a causal effect, not the number of conversions credited to a channel.
- RevenueRevenue is the total income generated by the sale of goods or services related to a company's primary operations.