Can someone explain to me how the shift differential works?

I started working as a nursing assistant in the day shift. However, I worked at night to cover for someone. I heard at night I get paid $1.50 more than my day shift pay. I just checked my payroll, and it says the amount of hours for the day and shift 2. however, for shift 2 it's a small amount and i didn't get paid 1.50 more than my day shift pay. can someone explain to me how this works?

let's say I get $16 an hour for the day hours. if i work the night shift, don't i get paid 17.50 an hour for 8 hours? it doesn't show it like that on my payroll
It can be calculated two ways:Ex:$16 x 8 hours = $128 $1.50 x 8 hours = $12Add them together = $140Or$17.50 x 8 hours = $140

Doesn't matter what we say. You need to find out from your employer how they work it. And it is entirely possible they made a mistake. Find out.

Every facility's system is a little different and it will look different on your pay stub depending on your facility.