They will always disagree, sometimes by a factor of five or more. Both can be working perfectly.
Why the server shows more
- It counts bots. Analytics mostly does not.
- It counts requests where the visitor left before the page finished loading.
- It counts visitors with JavaScript disabled, and requests for files rather than pages.
Why Analytics sometimes shows more
- Caching. A page served from a cache – on the server, or at a content delivery network – may never reach your web server logs at all, while the JavaScript still runs in the browser and reports the visit.
Why Analytics shows less than reality
- Ad and tracker blockers stop the script running. Depending on your audience this can be a significant proportion.
- Visitors who decline analytics cookies, if your consent banner is set up correctly.
Which number to use
Use each for what it is good at. Analytics for audience, behaviour and marketing decisions. Server statistics for load, bandwidth and working out what is consuming resources.
What matters in both is the trend. The absolute number from any single tool is an estimate; the direction it is moving is the useful part.
