Authoritative definitions of the International System of Units and SI prefixes.
Dedicated unit pair
Atmospheres to Bar
Convert atm to bar instantly, then review the formula, assumptions, and rounding guidance.
Pressure & stressInstant result
Decimals
Formula result = input × 101325 ÷ 100000. 1 atm = 1.0133 bar
Common examples
One value, several units
Pascals101,325 Pa
Kilopascals101.325 kPa
Megapascals0.1013 MPa
Bar1.0133 bar
Pounds per square inch14.6959 psi
Millimetres of mercury759.9999 mmHg
Conversion table
| atm | bar |
|---|---|
| 1 atm | 1.0133 bar |
| 2 atm | 2.0265 bar |
| 5 atm | 5.0663 bar |
| 10 atm | 10.1325 bar |
| 25 atm | 25.3313 bar |
| 50 atm | 50.6625 bar |
| 100 atm | 101.325 bar |
Conversion chart
1 atm1.0133 bar
5 atm5.0663 bar
10 atm10.1325 bar
25 atm25.3313 bar
50 atm50.6625 bar
Worked example
Standard atmosphere is 101,325 pascals.
Unit definition
Atmospheres (atm) One atmospheres equals 101,325 pascal.
Unit history
Atmospheres is represented here using its modern SI definition or an internationally accepted relationship to an SI base unit.
Step by step
1. Parse the value, including fractions.
2. Convert atm to pascal.
3. Convert the base value to bar and apply your display precision.
Understand the result before using it
Atmospheres to Bar converts a value measured in Atmospheres (atm) into the equivalent value in Bar (bar). The numerical value changes because the size and definition of the selected unit changes; the underlying quantity does not.
Calculated result
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.
Formula, assumptions, and example
Formula
result = input × 101325 ÷ 100000
Assumptions
- Atmospheres and Bar represent the same pressure & stress quantity.
- The input is expressed in atm; the output is expressed in bar.
- The unit definitions and conventional relationship shown on this page apply.
Worked example
1 atm = 1.01325 bar. For another value, apply the same relationship and round only to the precision your source measurement supports.
When to use it
Good uses
- Read a atm measurement in a document that expects bar.
- Compare a atmospheres value with a value reported in bar.
- Check the atm-to-bar arithmetic before copying the result into another calculation.
Limitations
Common mistakes to avoid
- Do not confuse atm with another unit that has a similar name or symbol.
- Round the output to a precision justified by the original measurement.
- Verify safety-critical, regulated, laboratory, and contractual conversions against the controlling standard.
Sources and further reading
These references explain the underlying standards or provide authoritative context. Your own contract, institution, clinician, product documentation, local code, or governing standard may be the controlling source.
Guidance on unit names, symbols, conversions, and numerical presentation.
Questions about this calculation
How do I convert Atmospheres to Bar?
result = input × 101325 ÷ 100000 Using the displayed relationship, 1 atm equals 1.01325 bar.
How many Bar are in one Atmospheres?
One Atmospheres is 1.01325 Bar. The displayed digits may be rounded.
Can I reverse the atm to bar conversion?
Yes. Swap the source and target units in the converter. The reverse relationship converts bar back to atm.
Is the Atmospheres to Bar result exact?
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.