How many PSI are in 1 atmosphere?

One standard atmosphere (atm) equals approximately 14.696 PSI (often rounded to 14.7 PSI). This is the average atmospheric pressure at sea level.

What is a standard atmosphere?

A standard atmosphere (atm) is defined as exactly 101,325 pascals (101.325 kPa). It approximates the average atmospheric pressure at sea level at 15°C. It equals 14.696 PSI, 1.01325 bar, or 760 mmHg.

What is the PSI at sea level?

Standard atmospheric pressure at sea level is 14.696 PSI (1 atm). Actual sea-level pressure varies with weather, typically ranging from about 14.2 to 15.2 PSI.

How to Convert Atmospheres to PSI - Formula, Examples & Chart

The Atmospheres to PSI Formula

PSI = Atmospheres × 14.6959

One standard atmosphere is defined as exactly 101,325 pascals. One PSI equals approximately 6,894.76 pascals. Dividing 101,325 by 6,894.76 gives us 14.6959 PSI per atmosphere.

Step-by-Step Examples

Example 1: 2 Atmospheres (Scuba Diving at 10 m Depth)

Calculation: 2 × 14.6959 = 29.39 PSI.
Result: 2 atm = approximately 29.4 PSI.

Example 2: Hyperbaric Chamber at 3 atm

Calculation: 3 × 14.6959 = 44.09 PSI.
Result: 3 atm = approximately 44.1 PSI.

Example 3: Vacuum at 0.5 atm

Calculation: 0.5 × 14.6959 = 7.35 PSI.
Result: 0.5 atm = approximately 7.35 PSI (half standard pressure).

Pressure Unit Reference Table

Atmospheres	PSI	Bar	kPa	mmHg
0.5	7.35	0.507	50.66	380
1.0	14.70	1.013	101.33	760
1.5	22.04	1.520	151.99	1,140
2.0	29.39	2.027	202.65	1,520
3.0	44.09	3.040	303.98	2,280
5.0	73.48	5.066	506.63	3,800
10.0	146.96	10.133	1,013.25	7,600

Real-World Applications

Scuba Diving

Divers experience an increase of approximately 1 atmosphere for every 10 meters (33 feet) of seawater depth. At 30 meters, the pressure is 4 atm or about 58.8 PSI. Understanding pressure is critical for safe dive planning.

Chemistry and Physics

Many chemical reactions and gas law calculations use atmospheres as the standard pressure unit. Converting to PSI helps when using American pressure gauges and equipment in laboratory settings.

Aerospace

Aircraft cabin pressure is typically maintained at 0.74-0.81 atm (equivalent to 6,000-8,000 feet altitude), or roughly 10.9-11.9 PSI. This is important for understanding cabin pressurization systems.

Quick Tip

For a fast estimate, multiply atmospheres by 14.7. For most practical purposes, 1 atm = 14.7 PSI is accurate enough. Use our pressure converter for precise calculations across all pressure units.