Pressure bar ↔ atm

1 atm = 1.01325 bar = 14.696 psi.

Inputs

Result

Loading calculator…
—

General calculation reads

Amazon affiliate
How Not to Be Wrong
Jordan Ellenberg - math thinking
Shop on Amazon
The Joy of X
Steven Strogatz - accessible math
Shop on Amazon
Scientific calculator (Casio fx-991EX)
Shop on Amazon

As an Amazon Associate we may earn from qualifying purchases. This does not add cost for you.

How to use this calculator

  • Pick direction + enter value.
  • Read all units.

About this calculator

1 atmosphere is the defined standard sea-level pressure: exactly 101,325 Pa = 1.01325 bar = 14.696 psi = 760 mmHg. Bar is metric round number (100 kPa). For most casual use, atm and bar are interchangeable (within 1.3%). Underwater pressure increases ~1 bar per 10 meters depth — so at 30m, total pressure is ~4 atm (1 atm air + 3 from water).

Frequently asked

Why two near-identical units?+
atm = historical (sea-level standard). bar = metric (round 100 kPa). Both used; ~1.3% different.
Sea-level pressure varies?+
Yes — by altitude (drops ~12 mb per 100m), weather (storms drop 30-50 mb), latitude (~10 mb).
Underwater pressure?+
1 atm at surface + 1 atm per 10 m depth. Diver at 30m = 4 atm absolute.
Vacuum chamber?+
Below 1 atm = vacuum. "High vacuum" = below 10⁻³ Pa. "Ultra high vacuum" = below 10⁻⁷ Pa.
When use atm?+
Chemistry, biology, geology — historical convention. Engineering: Pa or bar. Medicine: mmHg.

Related calculators

Pressure psi ↔ bar
1 bar = 14.5038 psi = 100 kPa = 0.987 atm.
Wind Speed mph ↔ Knots
1 knot = 1.15078 mph = 1.852 km/h. Bidirectional, also m/s.
Temperature Rankine ↔ Fahrenheit
R = F + 459.67. Rankine is absolute (0 = absolute zero); Fahrenheit + 460.
Gravity on Other Planets
Surface gravity table for solar system bodies.
Time Seconds ↔ Minutes / Hours
Convert seconds to days/hours/minutes/seconds; auto-format hh:mm:ss.
Density g/cm³ ↔ kg/m³
1 g/cm³ = 1000 kg/m³. Water = 1 g/cm³ = 1000 kg/m³.

More tools you might like

Hand-picked tools that pair well with this one — same audience, same intent.

Pressure psi ↔ bar
Calc

1 bar = 14.5038 psi = 100 kPa = 0.987 atm.

Wind Speed mph ↔ Knots
Calc

1 knot = 1.15078 mph = 1.852 km/h. Bidirectional, also m/s.

Gravity on Other Planets
Calc

Surface gravity table for solar system bodies.

Temperature Rankine ↔ Fahrenheit
Calc

R = F + 459.67. Rankine is absolute (0 = absolute zero); Fahrenheit + 460.

Time Seconds ↔ Minutes / Hours
Calc

Convert seconds to days/hours/minutes/seconds; auto-format hh:mm:ss.

Blood Pressure Calculator
Health

AHA blood-pressure category — normal, elevated, stage 1, stage 2, or hypertensive crisis.