Hello, I have a Ford Fiesta mk7 1.25 duratec 82 KM, I wanted to find out what the compression pressure is because the only thing I found was the compression ratio of 11.0: 1.

How long is a piece of string ?

The pressure in the cylinder is not constant and is effected by many things, some of which are the pressure of the incomming air, the pressure of the incomming fuel, the temprature of the cylinder, the speed of the engine. This is why you will not find the compression pressure listed. The compression ratio is of course constant and therefore the figure that is quoted for engines.

I mean the approximate pressure because it seems to be taking more oil.

I'm still not sure how you think this will help. Why don't you just do a simple compression test on each cylinder and compare them ?

Peak cylinder pressures near TDC (where spark occurs) will be in the range of 300 psi for engine's at light loads, to 1000 psi for engines at full power.

If you can actually get a compression tester in place, do a comparison between all the cylinders and see if one is lower than the others.  As Unofix states, there are a number of variables, but if all the cylinders are with 10% of each other, probably OK.  Never done it on a modern engine, so there may be added complications because of the "cleverness" of the ECU.

 I used to do it with engine hot, all plugs out, no air filter, and a well charged battery, (and in neutral!!) - last time was on a 2.8i Capri, about 12bar/175psi about 30 years ago

Ok i will do that thanks.