Assuming the density of sea water to be 1025 kg/m³ (in fact it is slightly variable), pressure increases by 1 atm with each 10 m of depth. Diver must alter their habits according to the pressure they experience.

Note that this calc gives the total pressure (not just the pressure due to the water), so it includes the 1 atm ambient air pressure at sea level.
Remember that the CalcTool units menu allows you to enter and output measurements convenient for you.