If I have the elevation 2500' and QNH 29,60 what is the pressure altitude? how I calculate it?

Question

If I have the elevation 2500' and QNH 29,60 what is the pressure altitude? how I calculate it?

Answer 1

(29.92-current pressure) x 1,000 + field elevation = PA

Answer 2

Pressure altitude is just the altitude the airplane will "think" it's at if it were a "standard" day.

If you're in the airplane at the airport, you can just set the altimeter to 29.92 and read the altitude.  It would indicate the pressure altitude, not the true airport elevation.

Or to calculate:  the pressure lapse rate is 1000' per inch, or 100' per .1", or 10' per .01".  29.92 (standard pressure) - 29.60 (current QNH) = .32" deviation from standard.  Since the pressure is lower than standard, the pressure altitude will be higher (lower pressure as you go up).  .32"=320 feet, so the pressure altitude is 2820".