It doesn't matter that you're measuring it in an odd way - pressure still has units of force per unit area. 1 "inch Hg" is 3386 Nm⁻². The fact that you can ex

It doesn't matter that you're measuring it in an odd way - pressure still has units of force per unit area. 1 "inch Hg" is 3386 Nm⁻². The fact that you can express length as "number of football fields" doesn't make length dimensionless.