Piston Area Calculator | Total Brake Caliper Piston Area

Total area of caliper pistons per axle in case of FIXED MOUNT calipers.

This is the area of one piston, multiplied by the number of pistons in one caliper, multiplied by the number of calipers on that axle.

In case of different piston diameters per caliper, calculate the area of every different piston, multiplied by the number in which every one of those different pistons occur in one caliper, add those numbers and multiply the result by the number of calipers on that axle.

Total area of caliper pistons per axle in case of SLIDING calipers: Do the calculation as described above and multiply the result by two.

The area of one piston = π • r² = ¼ • π • d² (π = 3.14)
So: the area of one piston = 0.785 • d • d (d = piston diameter in inches or millimeters)

If you prefer to have the math done by your PC, then enter the required numbers in one of the calculators below. You can overwrite/delete the current numbers. These are just popular values entered as an example.

REMINDER: For sliding calipers, multiply the result of the calculator by 2.

	Standard
N	=
d₁	= in
n₁	=
d₂	= in
n₂	=
d₃	= in
n₃	=

Total Caliper Piston Area
per Axle = in²


N	= number of calipers per axle*
d₁	= Ø of largest piston in caliper
n₁	= number of pistons with d₁
d₂	= Ø of 2^nd largest piston in cal.
n₂	= number of pistons with d₂
d₃	= Ø of 3^rd largest piston in cal.
n₃	= number of pistons with d₃

* Usually 2, although some classic sports and race cars have 4 calipers on the front axle (2 per wheel). NOTE: n₁, n₂, n₃ are per caliper; not per axle!

	Metric
N	=
d₁	= mm
n₁	=
d₂	= mm
n₂	=
d₃	= mm
n₃	=

Total Caliper Piston Area
per Axle = mm²