Skip to main content

Standard Atmosphere to Bar (atm to bar) Calculator & Formula

Rate this converter 0 of 0 ratings
Live Conversion • ISO 80000-4:2019 Certified
1 Standard Atmosphere = 1.01325 Bar
1 atm = 1.01325 bar • 1 bar = 0.986923 atm
Standard Atmosphere to Bar: One Standard Atmosphere is equal to 1.01325 Bars.
Certified Authority Value
1.01325000
bar
Exact: 1 bar ≡ 0.9869232667 atm
atm
atm
bar
bar 1.01325
Conversion Formula
To convert Standard Atmosphere to Bar, multiply by 1.01325
atm × 1.01325 = bar

Calculation: 1 atm × 1.01325 = 1.01325 bar

Common Standard Atmosphere to Bar Calculations

Quick-lookup reference table showing calculated equivalents for standard increments between Standard Atmosphere (atm) and Bar (bar).

Tap any row to calculate
Standard Atmosphere to Bar: Primary Direct Table (15 Steps)
Bar to Standard Atmosphere: Reciprocal Summary

Real-World Context & Everyday Benchmarks

Tap to load into converter

To help contextualize these units in everyday life, science, and engineering, here are verified real-world reference points for Standard Atmosphere (atm) and Bar (bar):

Standard Atmosphere References:

  • Standard mean international atmospheric air pressure at sea level and 15°C 1 atm
  • Water pressure increase experienced by deep-sea scuba diver per 10 meters of depth 1 atm

Bar References:

  • Standard atmospheric pressure at sea level (1.01325 bar) 1 bar
  • Commercial espresso machine coffee extraction group head pressure 9 bar
  • Standard scuba diving compressed breathing air cylinder pressure 200 bar
  • Deep ocean floor water pressure at bottom of the Mariana Trench 1086 bar
ISQ Dimension: [M L⁻¹ T⁻²] Coherent SI Unit: pascal (Pa) Chemical Engineering, Solutions & Physical Chemistry

How to Convert Standard Atmosphere to Bar

Converting Standard Atmosphere (atm) to Bar (bar) is a core calculation in Pressure and Stress, which measures the perpendicular force exerted by a fluid or contact load per unit surface area. This calculation navigates the boundary between the International Metric System (SI) and British Imperial / US Customary engineering standards. In contemporary metrology, Imperial units are defined in terms of exact SI standards via international agreements—notably NIST SP 811 and the 1959 International Yard and Pound Agreement. Exactly 1 Standard Atmosphere equals 1.01325 Bar, while 1 bar equals 0.986923 atm.

Direct Factor1 atm = 1.01325 bar
Inverse Ratio1 bar = 0.986923 atm
Conversion ScaleMetric SI to British Imperial / US Customary Bridge
First-Principles SI Derivation ProofNIST SP 811 / ISO 80000 Compliance

Mathematical Conversion Derivation via Coherent SI Base Unit

Under the International System of Quantities (ISQ), dimensional conversion between non-SI units is rigorously resolved by bridging through the coherent SI base unit (pascal (Pa)) without arbitrary rounding:

Vtarget=Vsource×(ksource→SIktarget→SI)V_{\text{target}} = V_{\text{source}} \times \left( \frac{k_{\text{source} \to \text{SI}}}{k_{\text{target} \to \text{SI}}} \right)
Universal Dimensional Conversion Law (ISO 80000 / NIST SP 811)
1. Source SI Bridge (ksource):1 atm = 101325 pascal (Pa)
2. Target SI Bridge (ktarget):1 bar = 100000 pascal (Pa)
Step-by-step substitution for Standard Atmosphere → Bar:V(bar) = V(atm) × ( 101325 / 100000 ) = V(atm) × 1.01325
Mathematical FormulaValue in Bar = Value in Standard Atmosphere × 1.01325Direct computational formula applied for standard conversion.
Worked Example

Evaluating an input of 120 Standard Atmosphere (atm) produces 121.59 Bar (bar). In heavy-duty utility and industrial workloads, 240 atm equals 243.18 bar.

Inverse check: 1 bar = 0.986923 atm.

Understanding Standard Atmosphere and Bar

Standard Atmosphere

atm
Standard Unit

A Standard Atmosphere (atm) is a recognized unit for pressure and stress.

Applications & Practical Context

In practical pressure terms, a standard mean international atmospheric air pressure at sea level and 15°C equals 1 atm, a water pressure increase experienced by deep-sea scuba diver per 10 meters of depth equals 1 atm.

Physical Setup

A pressure of 1 atm corresponds to 101325 Pa (exerting a perpendicular force of 101325 newtons per square meter).

Conversion to SI Unit: pascal (Pa)
1 atm = 101325 Pa

Bar

bar
Metric Unit

The bar (bar) is a non-SI metric unit of pressure widely used in meteorology, engineering, and diving.

Applications & Practical Context

In practical pressure terms, a standard atmospheric pressure at sea level (1.01325 bar) equals 1 bar, a commercial espresso machine coffee extraction group head pressure equals 9 bar, a standard scuba diving compressed breathing air cylinder pressure equals 200 bar.

Physical Setup

A pressure of 1 bar is defined as exactly 100,000 pascals (100 kPa), approximating standard Earth atmospheric air pressure at sea level (1.01325 bar).

Conversion to SI Unit: pascal (Pa)
1 bar = 100,000 Pa

Domain Metrology & Engineering Applications

Governing Law & Equation

Pascal's Principle of Fluid Pressure (P = F / A)

Measurement Instrumentation

Rigorously quantified in laboratory and field settings using primary deadweight piston gauges, piezoresistive silicon pressure transmitters, and Bourdon tube test gauges.

Primary Industry Sectors

Applied across aerospace hydraulic flight actuators, oil & gas pipeline monitoring, chemical autoclave pressure safety, and industrial compressed air under international metrology standard ISO 80000-4:2019, NIST SP 811.

Physical Orders of Magnitude & Laboratory Reference Benchmarks

Physical Phenomenon / Engineering ReferenceReference ValueConverted to Bar
Standard mean international atmospheric air pressure at sea level and 15°C1 atm1.01325 bar
Water pressure increase experienced by deep-sea scuba diver per 10 meters of depth1 atm1.01325 bar
Institutional Metrology & Standard Authority:

Formulas, conversion coefficients, and base definitions on this page strictly adhere to the ISO 80000-4:2019, NIST SP 811 and the BIPM SI Brochure (9th Edition). Governed by Pascal's Principle of Fluid Pressure (P = F / A) under ISO 80000 dimensional vector [M L⁻¹ T⁻²].

Multi-Variable Engineering Bridge Fluid Power & Contact Mechanics

Hydraulic Cylinder & Contact Force Bridge (kN • lbf • Metric Tons • Bar • PSI • Pascals)

Calculate total thrust, clamp load, or bolt pretension from hydrostatic pressure [M L⁻¹ T⁻²] acting over cross-sectional geometry [L²] via Pascal's hydraulic principle F = P × A.

F = P × A
Live Calculated Bridge Equivalent:
1 atm at 100mm (4-inch) Standard Industrial Hydraulic Bore = 0.7958 kN
Equals 178.9044 lbf • 0.08115 t-force • 795.8066 N
Civil & Press Metric
0.7958
kN
Kilonewtons
US Hydraulic Standard
178.9044
lbf
Pounds-Force
Press Capacity
0.08115
t-force
Metric Tons Force
SI Standard
795.8066
N
Newtons
US Press Rating
0.08945
ton-force (US)
Short Tons Force
Workshop Standard
81.1497
kgf
Kilograms-Force
  1. 1. Normalize Input to SI Base Unit (Pa):
    P = 1 atm × 101325 = 101325 Pa
  2. 2. Apply Engineering Parameter (A):
    Selected condition: 100mm (4-inch) Standard Industrial Hydraulic Bore at A = 0.007854 m²
  3. 3. Execute Governing Physical Law in SI Units:
    F = P × A = (101325) × (0.007854) = 795.80655 N
  4. 4. Convert to Standard Engineering Units:
    • kN: 795.80655 × 0.001 = 0.7958 kN (Kilonewtons) • lbf: 795.80655 × 0.2248 = 178.9044 lbf (Pounds-Force) • t-force: 795.80655 × 0.000102 = 0.08115 t-force (Metric Tons Force) • N: 795.80655 × 1 = 795.8066 N (Newtons) • ton-force (US): 795.80655 × 0.0001124 = 0.08945 ton-force (US) (Short Tons Force) • kgf: 795.80655 × 0.102 = 81.1497 kgf (Kilograms-Force)
Explore Full Area Converter →
Engineering Substance / Operating Standard Parameter Value (m²) Reference State / Condition Typical Industrial & Engineering Application
25mm (1-inch) Micro Pneumatic Bore 0.0004909 Area = π × (0.0125m)² Automation grippers & electronic assembly tooling
50mm (2-inch) Medium Pneumatic Ram 0.001964 Area = π × (0.025m)² Industrial packaging presses & clamping fixtures
100mm (4-inch) Standard Industrial Hydraulic Bore 0.007854 Area = π × (0.05m)² Excavator booms, log splitters & machine shop presses
150mm (6-inch) Heavy Mobile Hydraulic Ram 0.01767 Area = π × (0.075m)² Mining shovels, dump truck lifts & forge actuators
200mm (8-inch) Massive Press Cylinder 0.03142 Area = π × (0.10m)² Automotive body stamping presses & scrap balers
Vehicle Road Contact Patch (4 Car Tires) 0.06 4 × 150 cm² tire patches Total passenger tire road contact footprint
Standard M12 High-Strength Bolt Tensile Area 8.43 × 10⁻⁵ ISO 898-1 stress area 84.3 mm² Flange fastener clamping stress analysis
Standard M20 Structural Bolt Tensile Area 0.000245 Stress area 245 mm² Heavy structural steel framing & anchor rods
1.0 Square Meter Reference Plate Area 1 1.0 m × 1.0 m area Architectural wind load & hydrostatic flood gate
Embed
Need this Standard Atmosphere to Bar calculator on your website, lab portal, or research blog?
Free HTML Widget 100% Responsive Zero Cookie Tracking
Notice a calculation discrepancy, rounding error, or glitch?
Help us maintain 100% scientific precision and report any issues directly to engineering.

Frequently Asked Questions

There are exactly 1.01325 bars (bar) in 1 standard atmosphere (atm). To calculate larger amounts manually, simply multiply your total number of standard atmospheres by the conversion multiplier of 1.01325.

The mathematical formula to convert standard atmospheres to bars is: [value] * 1.01325 = bars. Rather than doing the math manually, you can use our high-precision online calculator to process this exact equation instantly without rounding errors.

To perform the reverse calculation from bars back to standard atmospheres, you must divide your starting value by 1.01325. Our bidirectional tool automatically computes this inverse equation the moment you type into the bar input field.

1 Standard Atmosphere is larger than 1 Bar. Specifically, 1 Standard Atmosphere equals exactly 1.01325 bars, making it 1.0133 times larger (a difference of 0.01 orders of magnitude). Therefore, quantities expressed in bars require a larger numerical value to represent the same physical amount.

A typical standard mean international atmospheric air pressure at sea level and 15°C measures 1 atm, which corresponds to 1.0133 bar (Bar).

There are exactly 1.01325 Bar in 1 Standard Atmosphere (1 atm = 1.01325 bar).

The conversion formula is V(bar) = V(atm) × 1.01325.

To convert in reverse, use the formula V(atm) = V(bar) × 0.986923.

Under standard conditions, 1 atm is slightly greater than 1 bar (100 kPa), precisely defined as 1.01325 bar.