Audio Systems: amp size, ohm speaker, ohm load

Question
My amp is a 2.5. What watt is it?

Answer
I need more information in order give a reliable answer.

If the ac current to the load is 2.5 amp rms then depending on the load, the power rating would be i**z or current squared times the impedance of the speaker load.  So, a 4 ohm load - if the amp is rated for a 4 ohm speaker - would be 25 watts.  An 8 ohm load rating for the amp would be a 50 watt unit.

But, give me a model number or something to verify the specifications and we can be more specific and accurate.  The above is just a guess based on your inadequate information.

Have a nice day.