Hello,
I have a kitchen appliance that is 240v 12.5 amps. My question is will 12.5 amps the combined amperage on both legs (12.5 amps on each phase) or is it 6.25 amps on each leg. I know the amperage will vary according to amount of load on the appliance and won't be exact.

Thank you

Amps are not combined. You have 12.5 amps per leg.

The correct way of stating this is you have 12.5 amps @ 240v, or 3000 watts.

Thanks for your answer stanfortyman.
So I assume using an amp meter, each leg should read roughly the same amperage...

Yes, IF this is a straight 240v appliance.
Many kitchen appliances are 120/240v requiring a neutral because they have 120v loads as well as 240v loads. In this case the load will most likely be unbalanced.

There is no neutral connection for this appliance. It is a deep fryer that is built into the kitchen counter.