How do you calculate manifold absolute pressure?

Manifold absolute pressure (MAP) can be calculated by measuring the pressure inside the intake manifold relative to a vacuum. It is typically expressed in inches of Mercury (inHg) or kilopascals (kPa). The formula to calculate MAP is: MAP = Barometric Pressure - Vacuum Pressure + Atmospheric Pressure. In practice, automotive MAP sensors provide direct readings of this pressure, factoring in ambient atmospheric conditions.