How does pressure increase as you dive deeper?

Pressure increases by 1 atmosphere (ATA) for every 10 meters (33 feet) of seawater. At the surface, you are already at 1 ATA.

What is the standard recreational diving depth limit?

Most recreational diving agencies set a hard limit of 40 meters (130 feet). Deeper dives require specialized decompression training and equipment.

How do you calculate pressure at depth?

The formula for salt water is: (Depth in meters / 10) + 1 = Pressure in ATA. For feet, it is: (Depth in feet / 33) + 1 = Pressure in ATA.

Why does freshwater depth exert less pressure than salt water?

Salt water is denser (approx. 1025 kg/m³) than fresh water (1000 kg/m³). Therefore, you must dive slightly deeper in fresh water—about 10.3 meters or 34 feet—to gain an additional atmosphere of pressure.

Scuba Diving & Maritime

Dive Depth Converter

Analyze the abyss. Convert depth metrics and calculate precise ambient pressure for safe recreational and technical diving.

Measurement Entry

Saltwater Depth (Meters)

Saltwater Depth (Feet)

Pressure at Depth

Ambient Pressure (ATA)

3.0

Pressure (BAR)

3.04

Pressure (PSI)

44.1

The Laws of Diving Physics

Boyle's Law

States that pressure and volume are inversely proportional. As you descend, the air in your lungs and equipment compresses. At 10m (2 ATA), air volume is halved; at 30m (4 ATA), it is reduced to one-fourth.

Dalton's Law

Concerned with partial pressures. As you dive deeper, the partial pressure of nitrogen and oxygen increases, which can lead to Nitrogen Narcosis or Oxygen Toxicity at extreme depths.

Depth Reference Chart

Meters	Feet	ATA	Notes
0	0	1.0	Surface Level
10	33	2.0	OWD Limit (Approx)
20	66	3.0	Advanced OWD Depth
30	99	4.0	Nearing Recreational Limit
40	132	5.0	Hard Recreational Limit