I’ve calibrated my ph pen but when I turn it on it reads1.25 do I need to calibrate again or do the math for the ph I want

It needs to be in a solution for a reading. If you just turn it on and keep it out of water for example it won't be reading anything so I'm assuming that's why it's showing 1.25

i would certainly attempt to re calibrate . 1.25 is like pure acid. what does it read when put into straight tap water?

I'd try to calibrate it again, but that's just 1 man's opinion.