CRO Audit vs UX Audit vs Site Speed Audit: Which One Do You Actually Need?
You searched for why your site isn't converting, and you got three different pitches. One agency wants to run a UX audit. A freelancer is selling a site speed audit. Somebody else is offering a CRO audit. All three describe the same symptom on their sales page: you have traffic, you aren't making money.
They are not the same service. They measure different things, they produce different deliverables, and buying the wrong one is how people spend money and change nothing.
What each one actually measures
A site speed audit measures load performance. Time to first byte, largest contentful paint, render-blocking scripts, image weight, third-party tag bloat. The deliverable is a technical punch list, usually aimed at your developer. It answers one question: how fast does this thing load, and what is making it slow?
Is your site converting as well as it could be?
Get a CRO Audit - $99A UX audit measures usability. Can people find what they need, complete tasks, and understand where they are? It draws on interface conventions, accessibility standards, and sometimes real user testing. The deliverable is usually a set of interface recommendations, often with wireframes. It answers: is this thing confusing?
A CRO audit measures revenue leakage. It starts from the money, works backward through the path a buyer takes, and asks where people are dropping out and why. It covers positioning and messaging, offer clarity, objection handling, trust signals, the form or checkout, and yes, both speed and usability where they're costing you sales. The deliverable is a prioritized list of fixes ranked by what they're likely worth.
The short version: speed is a subset of UX, and UX is a subset of CRO. Each one is a wider aperture than the last.
Where they genuinely overlap
Any competent CRO audit will flag your load times, because slow pages lose sales. Any competent UX audit will flag a confusing checkout, and so will a CRO audit. The overlap is real, and anyone who tells you these are three completely separate disciplines is selling you three things.
The difference is the question being asked. A speed audit tells you your hero image is 4MB. A CRO audit tells you your hero image is 4MB and that the headline sitting on top of it doesn't say what you sell, and that the second problem is costing you more than the first.
That's the part that matters. Not what gets found, but what gets ranked.
How to tell which one you need
Get a site speed audit if you already know your conversion path works and the complaint is specifically about slowness. Your PageSpeed score is in the red, your bounce rate spikes on mobile, and you have a developer ready to act on a technical list. If you don't have someone who can implement it, a speed audit is a PDF you will not use.
Get a UX audit if you're running a product or app where people come back repeatedly, and the problem is task completion rather than a first purchase decision. Onboarding flows, dashboards, multi-step account setup. UX research earns its cost when the interface is complicated and used more than once.
Get a CRO audit if you're paying for traffic and the return isn't there, or your site gets visitors and they leave without buying. This is most small businesses and most DTC stores. Your problem usually isn't one broken thing. It's four or five medium things stacked on top of each other, and you don't know which to fix first.
The trap: buying the narrow one because it's cheaper
Speed audits are the easiest of the three to sell, because the tooling is free and the output is automatic. You can run PageSpeed Insights on your own site in ten seconds and get most of what a cheap speed audit will tell you.
What you can't get automatically is judgment about what to do first. That's the actual product. A tool will hand you nineteen items with no sense of which two are worth your Saturday. If the deliverable you're buying could have been generated by a script, you didn't buy an audit. You bought a report.
What I do, and where the line is
I run CRO audits. Full conversion analysis of a site or landing page, every fix prioritized by expected impact, delivered in one business day for $99. Speed and usability are inside that, because they affect conversions, and I'm not going to ignore a 6 second mobile load just because it's technically somebody else's category.
Here's the honest line. If you're a SaaS company with a complex product and real research budget, a dedicated UX study with actual moderated user sessions will tell you things I can't. If your only issue is that a developer bloated your theme, hire the developer. I'd rather tell you that than sell you the wrong thing.
But if you have traffic and no sales, and you can't tell where it's going wrong, that's a conversion problem. Here's what I usually find when I look, and here is a real audit start to finish if you want to see the document itself. And if you want me to look at yours, the audit is here.