Glass table top - how big can I go? How much over hang is safe?

apples1

We have a rectangular trestle style table. Oak trestle and glass top. The glass sits on metal disks with small rubber rings on top. The glass is scratched and we'd like to replace with a slightly bigger top so we can fit 8 chairs more comfortably. Current glass size is 180 x 90 and want to 200 x 90.

How does one calculate the amount of glass it is safe to overhang the end. The current overhang is 43cm - can we go up to 53cm overhang each end? Glass is 1cm thick.

apples1

Anyone have any idea how I can find out the answer please?

AlwaysSomething

For what you want to do, just go ahead. There are engineering calculations you can do to work this kind of thing out exactly, but they always include a large safety factor. One engineer might use a safety factor of 2, another engineer would choose 3. So they would come up with very different answers. What you want to do is just a small percentage change, and would fall well within normal safety factors. If you want to be super careful, go up 1mm in thickness - you will end up with a stronger solution than the original. Not necessary though.
Make sure you use toughened glass. It is much stronger, and also a bit safer in the unlikely event that it breaks. Your original table top will be toughened glass.
For info, I have this coffee table

It's 110cm long, and is rated 80kg - more than a lot of people weigh. So glass is pretty strong stuff.