How much is the sea pressure at 100 feet?

At a depth of 100 feet (approximately 30.48 meters) in the ocean, the pressure increases due to the weight of the water above. The atmospheric pressure at sea level is about 14.7 pounds per square inch (psi), and water exerts approximately 0.43 psi for every foot of depth. Therefore, at 100 feet, the total pressure is about 43 psi from the water plus 14.7 psi from the atmosphere, resulting in approximately 57.7 psi.