What is the difference between "at" and "atm"?

Different units! (Common source of confusion) at (technical atmosphere) : 1 at = 1 kgf/cm² = 98,066.5 Pa Engineering unit based on kilogram-force Symbol: at Historical European engineering atm (standard atmosphere) : 1 atm = 101,325 Pa (exactly, by definition) Based on sea-level atmospheric pressure Symbol: atm Scientific/meteorological standard Relationship : 1 atm = 1.033 at (about 3% higher) Why confusion? : Names sound similar, values close (both ≈ atmospheric pressure) Technical Atmosphere to Atmosphere converter →

How do I convert at to bar?

Formula : bar = at × 0.980665 Quick approximation : 1 at ≈ 1 bar (1.9% difference) Exact conversions : 1 at = 0.981 bar 2 at = 1.961 bar 5 at = 4.903 bar 10 at = 9.807 bar 100 at = 98.07 bar Inverse : 1 bar = 1.0197 at Why so close? : Bar defined (originally) to be close to atmospheric pressure, similar motivation as technical atmosphere at to Bar converter →

How do I convert at to PSI?

Formula : PSI = at × 14.2233 Examples : 1 at = 14.22 PSI 2 at = 28.45 PSI 5 at = 71.12 PSI (typical air compressor) 10 at = 142.23 PSI 100 at = 1,422.33 PSI (high pressure) Inverse : 1 PSI = 0.0703 at Memory aid : 1 at ≈ 14 PSI at to PSI converter →

How do I convert at to kPa or MPa?

Formula : kPa = at × 98.0665 Examples : 1 at = 98.07 kPa ≈ 0.1 MPa 5 at = 490.3 kPa ≈ 0.5 MPa 10 at = 980.7 kPa ≈ 1 MPa 50 at = 4,903 kPa ≈ 5 MPa 100 at = 9,807 kPa ≈ 10 MPa Quick rule : Multiply by ~100 to get kPa, divide by ~10 to get MPa at to kPa converter → at to MPa converter →

Why is this unit not used anymore?

SI adoption (1970s-1980s): Most countries transitioned to SI units (Pa, kPa, MPa, bar) Problems with technical atmosphere : Not SI-compliant : Based on kilogram-force (gravitational unit) Ambiguity : "kg" is mass, not force (kgf needed for clarity) Gravity dependence : Assumes standard gravity (9.80665 m/s²) Confusion : Easy to confuse with standard atmosphere (atm) Modern replacements : Bar : 1 at ≈ 1 bar (easy conversion) kPa : 1 at ≈ 100 kPa MPa : For high pressures (1 at = 0.1 MPa) Still seen in : Older European equipment specifications Chinese industrial standards (some applications) Russian/former Soviet engineering documents Japanese industrial equipment (occasionally) Legacy pressure gauges and instruments For new designs : Use bar, kPa, or MPa instead of at Historical importance : Was convenient unit when bar not yet standardized, and provided easy mental approximation to atmospheric pressure.

Technical Atmosphere (at) - Unit Information & Conversion

Symbol:at

Plural:technical atmospheres

Category:Pressure

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What is a Technical Atmosphere?

Technical atmosphere (at, symbol for technische Atmosphäre) = 1 kgf/cm² = 98,066.5 Pa ≈ 0.968 atm ≈ 14.22 PSI. Historical metric engineering unit. Used in older European/Asian engineering, hydraulics. Different from standard atmosphere (atm).

History of the Technical Atmosphere

Defined as pressure from 1 kilogram-force per square centimeter. Standard in European engineering (Germany, Austria) until SI adoption 1970s-1980s. Still used in some Asian countries (China, Russia). Chosen because 1 at ≈ 1 atm (atmospheric pressure), making mental calculations easier.

Quick Answer

What is Technical Atmosphere? Technical atmosphere (at) = 1 kgf/cm² = 98,066.5 Pa ≈ 14.22 PSI ≈ 0.968 atm. Historical metric engineering unit (pre-SI). 1 at ≈ 1 bar ≈ 1 atmosphere (easy to remember). Still used in some Asian industries. Use our pressure converter for conversions.

Definition

1 at = 1 kgf/cm² = 98,066.5 Pa = 98.07 kPa = 0.9807 bar = 0.968 atm = 14.223 PSI = 735.6 mmHg

Symbol: at (from German "technische Atmosphäre")

Also written as: kgf/cm², kg/cm², technical atmosphere, metric atmosphere (not standard atmosphere!)

Physical meaning: Pressure exerted by 1 kilogram-force over 1 square centimeter

Common Uses

Historical: European engineering (Germany, Austria, Switzerland) pre-1980s. Current: Some Asian countries (China, Russia, Japan) still use occasionally. Older Equipment: Pressure gauges, hydraulic systems from mid-1900s. Legacy Specs: Old engineering drawings, technical manuals.

Real-World Examples

Approximate Equivalents (Easy to Remember)

1 at ≈ 1 atm (actually 1.033 at = 1 atm)
1 at ≈ 1 bar (actually 1.0197 at = 1 bar)
1 at ≈ 14 PSI (actually 14.22 PSI)

These approximations made mental calculations convenient in older engineering

Tire Pressures (Historical European Specs)

Bicycle: 4-6 at (58-87 PSI)
Motorcycle: 1.8-2.5 at (26-36 PSI)
Passenger car: 1.8-2.2 at (26-31 PSI)
Truck: 5-7 at (71-100 PSI)

Modern equivalent: Now specified in bar or kPa

Hydraulic Systems (Older European Equipment)

Low pressure: 5-10 at (71-142 PSI)
Medium pressure: 50-100 at (710-1,422 PSI)
High pressure: 150-250 at (2,133-3,554 PSI)
Very high pressure: 300-500 at (4,266-7,106 PSI)

Water & Steam Systems (Historical)

Municipal water: 2-6 at (28-85 PSI)
Steam boiler (low): 5-15 at (71-213 PSI)
Steam boiler (medium): 50-100 at (710-1,422 PSI)
Steam turbine: 100-300 at (1,422-4,266 PSI)

Industrial Compressed Air (Old Systems)

Workshop air: 6-8 at (85-114 PSI)
Pneumatic tools: 5-7 at (71-100 PSI)
Paint spraying: 2-4 at (28-57 PSI)
Compressed air storage: 10-15 at (142-213 PSI)

Material Testing (Pre-SI Specifications)

Concrete compressive strength: 150-400 at (2,133-5,688 PSI)
- Modern: 15-40 MPa
Steel yield strength: 2,500-4,000 at (35,560-56,896 PSI)
- Modern: 250-400 MPa

Technical Atmosphere Conversion Formulas

To Pascal:

1 at = 98066.5 Pa

Example: 5 technical atmospheres = 490332.5 pascals

To Kilopascal:

1 at = 98.0665 kPa

Example: 5 technical atmospheres = 490.3325 kilopascals

To Megapascal:

1 at = 0.098067 MPa

Example: 5 technical atmospheres = 0.490333 megapascals

To Hectopascal:

1 at = 980.665 hPa

Example: 5 technical atmospheres = 4903.325 hectopascals

To Bar:

1 at = 0.980665 bar

Example: 5 technical atmospheres = 4.903325 bars

To Millibar:

1 at = 980.665 mbar

Example: 5 technical atmospheres = 4903.325 millibars

To Atmosphere:

1 at = 0.967841 atm

Example: 5 technical atmospheres = 4.839206 atmospheres

To Torr:

1 at = 735.55924 Torr

Example: 5 technical atmospheres = 3677.7962 torr

To Millimeter of Mercury:

1 at = 735.55924 mmHg

Example: 5 technical atmospheres = 3677.7962 millimeters of mercury

To Inch of Mercury:

1 at = 28.959018 inHg

Example: 5 technical atmospheres = 144.79509 inches of mercury

To Pound per Square Inch:

1 at = 14.223343 psi

Example: 5 technical atmospheres = 71.116717 pounds per square inch

To Kilopound per Square Inch:

1 at = 0.014223 ksi

Example: 5 technical atmospheres = 0.071117 kilopounds per square inch

To Kilogram-force per Square Centimeter:

1 at = 1 kgf/cm²

Example: 5 technical atmospheres = 5 kilograms-force per square centimeter

To Kilogram-force per Square Meter:

1 at = 10000 kgf/m²

Example: 5 technical atmospheres = 50000 kilograms-force per square meter

To Millimeter of Water Column:

1 at = 10000 mmH₂O

Example: 5 technical atmospheres = 50000 millimeters of water column

To Inch of Water Column:

1 at = 393.70079 inH₂O

Example: 5 technical atmospheres = 1968.50395 inches of water column

Frequently Asked Questions

Different units! (Common source of confusion) at (technical atmosphere):

1 at = 1 kgf/cm² = 98,066.5 Pa
Engineering unit based on kilogram-force
Symbol: at
Historical European engineering atm (standard atmosphere):
1 atm = 101,325 Pa (exactly, by definition)
Based on sea-level atmospheric pressure
Symbol: atm
Scientific/meteorological standard Relationship: 1 atm = 1.033 at (about 3% higher) Why confusion?: Names sound similar, values close (both ≈ atmospheric pressure) Technical Atmosphere to Atmosphere converter →

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Symbol:at

Category:Pressure

System:Various

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Technical Atmosphere (at) - Unit Information & Conversion

🔄 Quick Convert Technical Atmosphere

What is a Technical Atmosphere?

History of the Technical Atmosphere

Quick Answer

Definition

Common Uses

Real-World Examples

Approximate Equivalents (Easy to Remember)

Tire Pressures (Historical European Specs)

Hydraulic Systems (Older European Equipment)

Water & Steam Systems (Historical)

Industrial Compressed Air (Old Systems)

Material Testing (Pre-SI Specifications)

Technical Atmosphere Conversion Formulas

Frequently Asked Questions

What is the difference between "at" and "atm"?

How do I convert at to bar?

How do I convert at to PSI?

How do I convert at to kPa or MPa?

Why is this unit not used anymore?

Convert Technical Atmosphere

Technical Atmosphere Quick Info

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