Six things you can check yourself.
Every one of these runs in your browser and sends nothing anywhere. They are estimates built on published benchmarks, and each one says which benchmark it used. An audit measures your own site directly, which is a different and more useful thing.
Speed and loss
What a heavy page costs.
Being found
What a search engine and an assistant can see.
These are estimates from published benchmarks and stated assumptions. None of them touches your site or sends data anywhere. If you want the real numbers for your own site, that is what the audit is for.
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