I'm trying to compute the water pressure as water comes out of a syringe.

I'm using a standard 10 cc syringe (15.8mm diameter), with a gauge 20 (green cannula .603mm inner diameter) attached to its end.

How can I compute for the water pressure coming out at the end? What formula will I use?

Do I need to time it?

I'm working on a small project. Thank you.