# Does a diameter of a brake line affect braking pressure

I am currently building a brake system for a vehicle ground up and I know that the diameter of the master cylinder would affect the braking force proportionally to the area of the master cylinder. But I was wondering if the diameter of the brake line would affect the braking pressure? I'm trying to be very precise with the braking force that's being delivered

Thanks!

Edit: If it does matter does anyone know what math formula I could use to determine the fluid pressure

• Diameter of pipe won’t affect the pressure unless it is so small that velocity losses become significant. As for a formula, check out Bernoulli. Commented Dec 8, 2020 at 7:09

According to Pascal's law, pressure must everywhere be equal. Pressure is defined as a force on a surface. Pressure equals force devided by area `P = F / a`. That is, the area of the master and slave cylinders (those inside the calipers or brake drums). So, brake pressure is only affected by the area of the master- and slave cylinders and the force that's applied to the brake pedal. This answers the question, but here is some more information:
Since `P = F / a`, `F = P . a`. If you have a master cylinder with a surface area of 10 cm^2, and you have a caliper with two 25cm^2 pistons, the total surface area in the caliper pistons is 5x greater, thus the force applied to the brake disk is multiplied by 5.