Is your HTML document unusually large?
It compares decompressed HTML bytes with the engine's document-size cutoffs.
What Check Engine measures
Successful pages above 400000 HTML bytes join the larger-document group. Pages above 150000 HTML bytes and at or below 400000 HTML bytes join the moderate group. Larger documents are reported first. If none exist, a moderate group above a 0.5 share of successful pages can produce the lower-severity finding. This measures the HTML document alone. Images and separate files need their own size measurements. For example, a document of exactly 400000 HTML bytes stays in the moderate size group.
The check reads HTML sizes from successful responses. A capped response gives only the amount retained. Keep the size unit and any read limit beside the result.
How to read the result
The larger-document finding is medium severity. Widespread moderate documents produce low severity. Browser loading time, script execution and page painting need separate measurements.
Why it matters
A large document can contain repeated markup or extensive inline data. Its byte count identifies something concrete to inspect, while a separate resource review is needed to understand the weight of the whole page.
How to fix it
Inspect the largest served documents and identify what fills them. Remove unused inline data and repeated markup, or split long listings when that suits the content. Move reusable assets only where the resulting requests and caching make sense. Compare decompressed HTML after the change and preserve the useful content the page was meant to deliver.
Page weight: how heavy is too heavy?
What we found in field audits
Problems in Speed & Core Web Vitals were found on 13 of the 14 sites we audited. These are area totals. Read the field-audit method.
Method note
backend/seo_engine/checks/performance.py, page_weight, revision 0bb8e8d3.
Common questions
What counts as a very large HTML document in this audit?
A successful page above 400000 HTML bytes enters the larger-document group. Separate page resources are outside this HTML-size measure.
Is an HTML document of exactly 400000 bytes in the larger group?
No. Exactly 400000 HTML bytes stays moderate. The larger group requires a strict excess over the limit.
How small can HTML be and still enter the moderate-weight group?
Moderate documents must exceed 150000 HTML bytes. A qualifying site's share of moderate pages can affect the lower-severity result.