Put a Dollar Figure on Slow Pages
Site Speed Revenue Calculator
✓ Monthly and annual revenue left on the table
✓ Current vs. projected conversion rate
✓ Lift model capped at 6 seconds, so it under-promises
✓ Sourced methodology, no email required
01 / Traffic
How many sessions does your store get a month?
Total monthly sessions across all channels, from your analytics. For example, 15,000.
02 / Current speed
What's your current average load time?
Use your largest contentful paint (LCP) on mobile if you have it, otherwise your best estimate. For example, 4.5. Measure it with PageSpeed Insights
03 / Target speed
What load time are you aiming for?
Google's own guidance targets under 2.5 seconds for a good mobile experience. Google's LCP threshold
04 / Conversion
What's your current conversion rate?
Sessions to purchase, store-wide. For example, 1.8.
05 / Order value
What's your average order value?
Blended AOV before discounts. For example, 65.
Revenue left on the table, per month
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Current conversion rate
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Projected conversion rate
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Annualized, that gap is —. Modeled using a 7% conversion lift per second of load time saved, capped at 6 seconds of improvement.
How this is calculated
Slower pages convert fewer visitors, and the relationship is well documented across independent studies of ecommerce load times. This tool models a conversion rate improving by roughly 7% for every second of load time you cut, up to 6 seconds of improvement. Beyond that range the relationship weakens, so the model caps there rather than extrapolating.
This is a directional estimate to size the opportunity, not a guaranteed outcome. Actual impact depends on your traffic quality, device mix, and what specifically is slowing the page down.
Measure your own load time
The calculator is only as good as the load time you feed it. Run your storefront through Google PageSpeed Insights and use the mobile Largest Contentful Paint it reports. Where field data is available it reflects real visitors rather than a lab run, which is the number worth modelling.
Sources
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Deloitte with Google, Milliseconds Make Millions
Across 37 retail and travel brands, a 0.1 second mobile speed improvement lifted retail conversions 8.4% and average order value 9.2%. That is a steeper slope than this tool models, which is why the figure here is the more conservative one.
deloitte.com, Milliseconds Make Millions -
Google, Core Web Vitals
Defines the field metrics Google uses to judge page experience, including Largest Contentful Paint, the load-time measure this tool asks for.
web.dev/articles/vitals -
Google, Largest Contentful Paint
Sets the under 2.5 second target used as the default in step 3, measured at the 75th percentile of real page loads.
web.dev/articles/lcp
Sources last checked August 2026.
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