How can I tell how many watts I'm I using on things. (like how many watts does A/C use.) how can I measure the watts I know volts and amps.

Power (W) = Volts x Amps

Just work it through

Multiply the two together, P = IV.

That's about all I can remember from A-LEVEL physics ;)

Ok do the folloing:-

check the A/C Amp multible in the main voltage for example
A/C is 5A X the voltage is 220 = 1100

regards
The roket 101

You would happen to pick the AC unit.

VA = Volt-Amps - loosely watts
Watts = V * I
Watts = V * I * Cos(theta) for AC circuits; Cos(0) = 1 for non-motor loads
FLA = Full load amps or what the unit draws at full load. Motors may not operate there.
LRA - Locked rotor amps. Usually what the motor draws at startup.

There is an inexpensive device in various varients called the Kill-a-Watt. It can help you determine energy usage for 120 V appliances that plug into the wall.

Remember too, that energy usage is time dependent, so the cost to run an AC depends on how long it's on.

I have a turbine 12volt how can I find how much in watts it generates OK with amps about 5 ampc

You added a new question to an old thread, that explains how to answer your question.

P=EI

Power = Volts times Amps

P= 12 x 5

Power = 60 watts