Convert Atmospheres to Bar
Instantly convert Atmospheres (atm) to Bar (bar) with our free online calculator.
Formula: atm to bar — multiply by 1.01325
Reference Table
| Atmospheres (atm) | Bar (bar) |
|---|---|
| 1 | 1.01325 |
| 5 | 5.06625 |
| 10 | 10.1325 |
| 25 | 25.3313 |
| 50 | 50.6625 |
| 100 | 101.325 |
How to Convert Atmospheres to Bar
Formula
To convert Atmospheres (atm) to Bar (bar): multiply by 1.01325
Step-by-Step
- Start with your value in Atmospheres (atm).
- Multiply by 1.01325 to perform the conversion.
- The result is your value expressed in Bar (bar).
Conversion Factor
1 atm = 1.01325 bar
Reverse Factor
1 bar = 0.986923 atm
Worked Example
Convert 25 Atmospheres to Bar: 25 atm = 25.3313 bar
About Atmosphere (atm)
A non-SI unit of pressure defined as exactly 101,325 pascals, corresponding to the standard sea-level atmospheric pressure as adopted by ISO 2533 and the BIPM SI Brochure. Atmospheres are the default reference pressure in physical chemistry (Standard Temperature and Pressure conventions: 1 atm at 273.15 K under IUPAC's 'STP' definition, though IUPAC has since moved to 1 bar STP), in commercial diving (depths are quoted in atmospheres absolute, with each 10 m of seawater adding ~1 atm), and in pressure-sensitive materials research where vapor pressure and saturation data are tabulated at 1 atm. A common pitfall: the "technical atmosphere" (at, 98,066.5 Pa = 1 kgf/cm²) used in some legacy European and Japanese engineering is NOT the same as the standard atmosphere — older pressure-vessel drawings can read 100 at and mean either depending on context. 1 atm = 1.01325 bar = 14.696 psi = 760 mmHg = 760 torr.
About Bar (bar)
A metric unit of pressure equal to exactly 100,000 pascals (100 kPa), approximately the average sea-level atmospheric pressure on Earth (1 atm = 1.01325 bar). Defined by IUPAC and accepted for use with the SI by the BIPM, the bar is not itself an SI-proper unit but is universally recognized in engineering. Bars are the default unit in European industry for compressed gas systems (compressed air at 6-10 bar shop pressure), hydraulics (mobile equipment at 200-400 bar working pressure), and chemical process plants. Car tire pressures in much of the world outside the US are specified in bar (a typical passenger car runs ~2.2 bar / 32 psi cold). Gauges on scuba cylinders (200 bar fill / ~2900 psi), brewery CO₂ tanks, fire suppression systems, and espresso machines (9 bar extraction pressure) all read in bar. 1 bar = 14.504 psi = 100 kPa = 0.9869 atm.
Quick Facts
- 1 Atmosphere equals 1.01325 Bar
- 1 Bar equals 0.986923 Atmospheres
- Atmosphere is a unit of pressure
- Bar is a unit of pressure
- This conversion is commonly used in tire inflation, weather reporting, scuba diving, and engineering
- The Bar belongs to the metric system
Common Atmosphere to Bar Conversions
| Atmospheres (atm) | Bar (bar) |
|---|---|
| 0.1 | 0.101325 |
| 0.5 | 0.506625 |
| 1 | 1.01325 |
| 2 | 2.0265 |
| 5 | 5.06625 |
| 10 | 10.1325 |
| 14.696 | 14.8907 |
| 15 | 15.1988 |
| 20 | 20.265 |
| 25 | 25.3313 |
| 50 | 50.6625 |
| 100 | 101.325 |
| 150 | 151.988 |
| 200 | 202.65 |
| 500 | 506.625 |
| 1000 | 1013.25 |
Understanding Atmospheres
The Atmosphere (symbol: atm) is a unit of pressure. A non-SI unit of pressure defined as exactly 101,325 pascals, corresponding to the standard sea-level atmospheric pressure as adopted by ISO 2533 and the BIPM SI Brochure. Atmospheres are the default reference pressure in physical chemistry (Standard Temperature and Pressure conventions: 1 atm at 273.15 K under IUPAC's 'STP' definition, though IUPAC has since moved to 1 bar STP), in commercial diving (depths are quoted in atmospheres absolute, with each 10 m of seawater adding ~1 atm), and in pressure-sensitive materials research where vapor pressure and saturation data are tabulated at 1 atm. A common pitfall: the "technical atmosphere" (at, 98,066.5 Pa = 1 kgf/cm²) used in some legacy European and Japanese engineering is NOT the same as the standard atmosphere — older pressure-vessel drawings can read 100 at and mean either depending on context. 1 atm = 1.01325 bar = 14.696 psi = 760 mmHg = 760 torr.
Atmospheres are commonly used in tire inflation, weather reporting, scuba diving, and engineering.
Understanding Bar
The Bar (symbol: bar) is a unit of pressure. A metric unit of pressure equal to exactly 100,000 pascals (100 kPa), approximately the average sea-level atmospheric pressure on Earth (1 atm = 1.01325 bar). Defined by IUPAC and accepted for use with the SI by the BIPM, the bar is not itself an SI-proper unit but is universally recognized in engineering. Bars are the default unit in European industry for compressed gas systems (compressed air at 6-10 bar shop pressure), hydraulics (mobile equipment at 200-400 bar working pressure), and chemical process plants. Car tire pressures in much of the world outside the US are specified in bar (a typical passenger car runs ~2.2 bar / 32 psi cold). Gauges on scuba cylinders (200 bar fill / ~2900 psi), brewery CO₂ tanks, fire suppression systems, and espresso machines (9 bar extraction pressure) all read in bar. 1 bar = 14.504 psi = 100 kPa = 0.9869 atm.
It belongs to the metric measurement system.
Bar are commonly used in tire inflation, weather reporting, scuba diving, and engineering.
Why Convert Atmospheres to Bar?
Engineers, mechanics, and scientists frequently need to convert pressure between Atmospheres and Bar when working with different measurement standards. Tire pressure, blood pressure readings, weather barometric measurements, and industrial process specifications may all use different pressure units depending on the region or discipline. Reliable conversion prevents equipment misuse and ensures safety.
Frequently Asked Questions
How do I convert Atmospheres to Bar?
A non-SI unit of pressure defined as exactly 101,325 pascals, corresponding to the standard sea-level atmospheric pressure as adopted by ISO 2533 and the BIPM SI Brochure. To convert Atmospheres to Bar, multiply by 1.01325. For example, 25 atm equals 25.3313 bar.
How many Bar are in 1 Atmosphere?
There are 1.01325 Bar in 1 Atmosphere.
How many Atmospheres are in 1 Bar?
There are 0.986923 Atmospheres in 1 Bar.
What is the formula for Atmosphere to Bar conversion?
The formula is: multiply by 1.01325. This means 1 atm = 1.01325 bar.
Is a Atmosphere bigger than a Bar?
No. One Atmosphere is smaller than one Bar because 1 atm equals 1.01325 bar, which is greater than 1.
When do you need to convert between Atmospheres and Bar?
A metric unit of pressure equal to exactly 100,000 pascals (100 kPa), approximately the average sea-level atmospheric pressure on Earth (1 atm = 1. Atmosphere and Bar are both pressure units, so conversion comes up whenever one source of information uses one unit and another uses the other — a classic cross-reference challenge in engineering, trade, travel, and everyday life.