i have a late 2013 imac can i upgrade to big sur

The big sur page states the oldest iMac is as you say 2014 whereas the app page states compatibility as OS X 10.9 or later.

These are different qualifications and not contradictory. Compatible Macs (such as a 2014 iMac or later) can update only from 10.9 (which is to say not earlier than 10.9) but it would be clearer if both specifications were stated. The support page says if a Mac is running 10.8 Mountain Lion then you first must upgrade to 10.11 El Capitan.

The App store will say if it is compatible with your computer. What does it say when you look at the Information panel? Mine says "Works on this iMac".

Unfortunately no. The oldest iMac capable of running Big Sur is the 2014.

See Apple's compatibility checklist here.

I have the same question. There appears to be conflicting information between the bigger page and the App store page. The big sur page states the oldest iMac is as you say 2014 whereas the app page states compatibility as OS X 10.9 or later. In my own case i'm running Catalina 10.15.7 so should be able to download Bigsur but it also says its not available when i try.

Yes I have the view button first and click that then get the get button and when I hit that it then whirrs and tells me it not available. Looks like as things are I’ll have to wait till they upgrade the iMac with the new Mac chip before I can get bigsur. I’m feel sure that earlier in the development of big sur I formed the impression that late 2013 iMacs could get bigsur in some of the advance publicity but as it stands I now can’t be bothered to try to track that back to find out where I formed that view.

https://support.apple.com/en-us/HT211238 This has the full list of compatible machines.

Mine says exactly the same but clicking on the down arrow along side it produces the older than 10.9 details

Does your App store page for Big Sur have the blue Get button on the top left? I get the same text "Requires macOS 10.9 or later" when I click the down arrow.