About

Pressure calculations are critical in environments where atmospheric conditions deviate from sea-level norms. Divers must monitor partial pressures to avoid toxicity, while pilots and meteorologists rely on accurate atmospheric data for navigation and forecasting. The Standard Atmosphere (atm) serves as the baseline reference, historically defined as the mean atmospheric pressure at mean sea level.

This tool converts atm into other essential units like PSI (common in mechanical gauges), bar (meteorology), and Pascals (SI unit). Accuracy here prevents equipment failure in hydraulic systems and ensures safety in hyperbaric medicine.

Formulas

The conversion relies on exact definitions established by international standards organizations.

P_Pa = P_atm × 101325

P_psi = P_atm × 14.6959

When calculating underwater pressure, remember that every 10 meters of depth adds approximately 1 atm of pressure.

Reference Data

Unit	Value (1 atm)	Context
Pascal (Pa)	101,325	SI Standard
Bar	1.01325	Meteorology
PSI	14.696	Imperial / Mechanics
Torr (mmHg)	760	Medical / Vacuum
cmH₂O	1,033	Fluid Dynamics
kgf/cm²	1.033	Technical Atmosphere

Frequently Asked Questions

This exact value was adopted in 1954 by the 10th Conférence Générale des Poids et Mesures (CGPM). It represents the mean atmospheric pressure at mean sea level at the latitude of Paris, serving as a universal baseline for thermodynamics and fluid mechanics.

At sea level, the pressure is 1 atm. For every 10 meters (33 feet) a diver descends, the pressure increases by 1 atm. A diver at 20 meters experiences 3 atm total (1 from air, 2 from water).

No. They are close but distinct. 1 bar equals 100,000 Pa, while 1 atm equals 101,325 Pa. The difference is roughly 1.3%, which is significant in high-precision scientific calibration.

Humans can survive at high pressures (saturation diving records exceed 70 atm) if the gas mixture is controlled. However, sudden changes (decompression) or oxygen toxicity at high partial pressures are the primary dangers.