Page Speed Revenue Calculator
Estimate what shaving seconds off your store is worth. Enter the numbers from your own analytics, set the uplift you think is realistic, and see the monthly and annual figures side by side.
Page Speed Revenue Calculator
Put a number on a faster store. Everything except the last field is your own analytics; the uplift assumption is yours to set, and published benchmarks range from about 1% to 8% per 0.1 second.
Extra revenue per month
Large enough to justify dedicated performance work
$12,870.00
Updates as you type — nothing is sent anywhere.
The uplift figure you enter is an assumption, not a measurement. Published benchmarks disagree by nearly an order of magnitude, none of them were measured on your store, and correlation studies cannot prove a speed change caused a conversion change. Treat the output as a way to size a decision, not as a forecast — and verify it afterwards against your own analytics.
Why the uplift is a field, not a constant
Most speed-ROI calculators bake in a single conversion figure and present the output as a prediction. We do not, because the published research disagrees far too much to pick a winner: Amazon's often-quoted finding was that every 100ms of latency cost about 1% in sales, while Deloitte's retail study reported a 0.1 second improvement lifting mobile conversions by 8.4%. That is nearly an order of magnitude between two credible sources, on different sites, in different years, measuring different things. Choosing one and hiding it inside the formula would turn an assumption into a claim. So the assumption is yours, it is visible, and it defaults to the conservative end.
How the calculation works
Baseline revenue is sessions multiplied by conversion rate multiplied by average order value. The time saved is the difference between your current and target load times, converted to tenths of a second and multiplied by your uplift figure to give a relative conversion uplift. That uplift is applied to baseline revenue to give the monthly gain, and multiplied by twelve for the annual figure. The uplift is capped at 100 percent — a doubling of conversions — because the published figures are marginal rates measured over small improvements, and extrapolating one linearly across several seconds produces numbers no store has ever achieved.
Where to find each input
Sessions, conversion rate and average order value all sit in Shopify Analytics under Reports, or in GA4 if you use it. Use a full month rather than a single week so promotions and weekday cycles average out. For load time, use field data rather than a lab score: the Core Web Vitals report in Google Search Console and the CrUX section of PageSpeed Insights both show what real visitors experienced, which is usually slower than a Lighthouse run on a fast connection. Largest Contentful Paint is the closest single metric to what a shopper perceives as load time.
What the model deliberately ignores
It assumes traffic and average order value stay flat, which is the conservative assumption — in practice faster sites also tend to rank and retain slightly better, so the revenue figure may understate the total effect. It also assumes the whole conversion change comes from speed. It cannot account for seasonality, a competitor's pricing, or the redesign that shipped in the same release. If you want to know what a speed change actually did, hold everything else still and compare like periods afterwards.
Turning the estimate into a decision
The number worth acting on is the annual figure set against the cost of the work. A store where the estimate is a few hundred pounds a month has other priorities; one where it runs into thousands has a straightforward business case. Either way the estimate is a starting point for a conversation, not a substitute for measuring the result. Run the same calculation again with your real post-launch numbers and you will know whether the assumption you entered was right.
Frequently asked questions
Is this page speed calculator free?
Yes. It runs entirely in your browser, needs no signup, and nothing you enter is sent anywhere.
What conversion uplift should I enter per 0.1 seconds?
Start at 1%, the conservative end and roughly Amazon's classic finding. Deloitte's retail study supports figures as high as 8.4% for mobile, but that is an upper bound from one dataset. If you have run your own before-and-after test, use your own number instead of either.
Can it tell me what my revenue will be after optimisation?
No, and no calculator can. It shows what the revenue would be if the uplift you entered turned out to be correct. The arithmetic is exact; the assumption behind it is not.
Which load time should I measure?
Largest Contentful Paint from field data — the Core Web Vitals report in Google Search Console, or the real-user section of PageSpeed Insights. Lab scores from a fast connection will flatter your store and overstate the gain.
Why is the conversion uplift capped?
Because the published figures are marginal rates measured across small improvements. Applied linearly to a three or four second saving they imply conversion increases several times over, which no store has recorded. The cap holds the output at a doubling of conversions at most.
Does a faster store help with anything besides conversion?
Yes. Core Web Vitals are a Google ranking signal, faster pages reduce bounce on paid traffic so ad spend goes further, and mobile visitors on poor connections are affected most. None of that is in the calculation, which is one reason the output leans conservative.