Hi, you can set a default zoom level for all sites (such as 100%), but you can also change the zoom level on each site by using the Ctrl and + key or Ctrl and - key, if you prefer you can instead use the zoom controls, which will be remembered for every time you visit that site, so that might be why Firefox sometimes zooms to 80%. More - Font size and zoom - increase the size of web pages.

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Hi, How can i stop firefox remembering?

You can try this: Type about:config into the address bar, press Enter and accept any warning, then copy and paste the following into the search box browser.zoom.siteSpecific Now on the search result, click the Toggle button at the right-hand end to change from True to False. You may have to restart Firefox to implement the change. Now only the zoom level on that tab should be remembered.