UnitsConverter

Technical Atmosphere to Hectopascal Converter

Convert technical atmospheres to hectopascals with our free online pressure converter.

Quick Answer

1 Technical Atmosphere = 980.665 hectopascals

Formula: Technical Atmosphere × conversion factor = Hectopascal

Use the calculator below for instant, accurate conversions.

Our Accuracy Guarantee

All conversion formulas on UnitsConverter.io have been verified against NIST (National Institute of Standards and Technology) guidelines and international SI standards. Our calculations are accurate to 10 decimal places for standard conversions and use arbitrary precision arithmetic for astronomical units.

Last verified: February 2026Reviewed by: Sam Mathew, Software Engineer

Technical Atmosphere to Hectopascal Calculator

How to Use the Technical Atmosphere to Hectopascal Calculator:

  1. Enter the value you want to convert in the 'From' field (Technical Atmosphere).
  2. The converted value in Hectopascal will appear automatically in the 'To' field.
  3. Use the dropdown menus to select different units within the Pressure category.
  4. Click the swap button (⇌) to reverse the conversion direction.
Share:

How to Convert Technical Atmosphere to Hectopascal: Step-by-Step Guide

Converting Technical Atmosphere to Hectopascal involves multiplying the value by a specific conversion factor, as shown in the formula below.

Formula:

hPa = at × 980.665

Example Calculation:

1 at = 980.665 hPa

Disclaimer: For Reference Only

These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.

Not for professional use. Results should be verified before use in any critical application. View our Terms of Service for more information.

Need to convert to other pressure units?

View all Pressure conversions →
📊 Pressure Table

Print-friendly conversion reference

📋 Unit Symbols

Copy at & hPa symbols

What is a Technical Atmosphere and a Hectopascal?

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

1 hPa = 100 Pa = 0.1 kPa = 1 mbar (exactly) = 0.001 bar = 0.0145 PSI = 0.000987 atm = 0.75 mmHg

Why Hectopascal?

The hectopascal perfectly bridges SI and traditional meteorology:

  • SI compliance: Uses SI base unit (Pascal)
  • Backward compatibility: 1 hPa = 1 mbar exactly (no conversion needed)
  • Convenient scale: Typical atmospheric pressure ~1,000 hPa (manageable numbers)
  • Global adoption: WMO (World Meteorological Organization) standard since 1980s

Note: The Technical Atmosphere is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Hectopascal belongs to the imperial/US customary system.

History of the Technical Atmosphere and Hectopascal

: The Transition from Millibar

The Evolution of Pressure Units

  • Pre-1900s: Mercury column (mmHg) standard for all pressure
  • 1900s-1980s: Meteorologists adopted millibar (mbar = 1/1000 bar)
    • Why: Sea level pressure ~1,013 mbar (convenient round number)
    • Advantage: Easy to work with 3-4 digit numbers
  • 1980s: International metric shift pushed for SI units
    • Problem: 1 mbar = 100 Pa (awkward multiplier)
    • Solution: 1 hectopascal = 100 Pa = 1 mbar (exact equivalence!)
  • 1980s-present: Smooth transition using hPa = mbar equivalence
    • No conversion confusion (same number, new name)
    • Allows decades of data to be "relabeled" without recalculation

Why This Worked

The brilliance: WMO chose hectopascal specifically because:

  1. 100 Pa = 1 hPa (clean, easy power of 10)
  2. 1 hPa = 1 mbar (exact, no confusion)
  3. Sea level pressure stayed ~1,013 hPa (same numbers as before)
  4. All existing meteorology infrastructure could transition seamlessly

Result: Weather services worldwide switched from mbar to hPa with zero data loss.

Common Uses and Applications: technical atmospheres vs hectopascals

Explore the typical applications for both Technical Atmosphere (imperial/US) and Hectopascal (imperial/US) to understand their common contexts.

Common Uses for technical atmospheres

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.

When to Use hectopascals

Meteorology: Weather forecasts, atmospheric pressure reporting (worldwide standard). Aviation: Altimeter settings, flight level pressure (ICAO standard). Oceanography: Atmospheric pressure corrections for sea level measurements. Climatology: Historical pressure data, pressure trends. Medical: Altitude acclimatization, pressure chambers, hyperbaric medicine.

Additional Unit Information

About Technical Atmosphere (at)

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.

About Hectopascal (hPa)

How do I convert hPa to PSI?

Formula: PSI = hPa × 0.0145

Examples:

  • 1,013 hPa = 14.7 PSI (sea level)
  • 1,000 hPa = 14.5 PSI
  • 900 hPa = 13.05 PSI
  • 800 hPa = 11.6 PSI

hPa to PSI converter →

Is hPa the same as mbar?

Yes, exactly! 1 hPa = 1 mbar

Why two names?:

  • Millibar (mbar): Traditional meteorology unit (1900s-1980s)
  • Hectopascal (hPa): SI-compliant name (1980s-present)
  • Same value, just renamed for SI consistency

Conversion: None needed! They're identical.

Modern usage: Weather services worldwide now use hPa, but many pilots and mariners still say "millibar."

What is normal atmospheric pressure in hPa?

Standard sea level: 1,013.25 hPa (exactly, by definition)

Typical range: 980-1,050 hPa depending on weather

Pressure variations:

  • Fair weather (high): 1,020-1,040 hPa
  • Normal range: 1,000-1,020 hPa
  • Stormy (low): 980-1,000 hPa
  • Hurricane: <980 hPa

Regional/seasonal: Varies ±30 hPa from standard

How does pressure change with altitude?

Rough approximation: Pressure decreases ~12 hPa per 100m near sea level

More accurate (ISA model):

| Altitude | Pressure (hPa) | % of Sea Level | |----------|---------------|----------------| | 0m | 1,013 | 100% | | 500m | 955 | 94% | | 1,000m | 899 | 89% | | 2,000m | 795 | 78% | | 3,000m | 701 | 69% | | 5,000m | 540 | 53% | | 8,848m (Everest) | 313 | 31% |

Formula (approximate): P = 1013 × (1 - altitude/44,300)^5.255

What hPa is considered high or low pressure?

High pressure (anticyclone):

  • Strong high: >1,030 hPa (stable, clear weather)
  • Moderate high: 1,020-1,030 hPa (fair weather)

Normal pressure: 1,005-1,020 hPa

Low pressure (cyclone):

  • Moderate low: 990-1,005 hPa (cloudy, possible rain)
  • Strong low: 970-990 hPa (rain, wind)
  • Very low: <970 hPa (storms, gales)

Extreme low: <920 hPa (major hurricanes/typhoons)

Context: Depends on region and season. 1,000 hPa may be "low" in winter anticyclone, "high" in tropical region.

Conversion Table: Technical Atmosphere to Hectopascal

Technical Atmosphere (at)Hectopascal (hPa)
0.5490.333
1980.665
1.51,470.998
21,961.33
54,903.325
109,806.65
2524,516.625
5049,033.25
10098,066.5
250245,166.25
500490,332.5
1,000980,665

People Also Ask

How do I convert Technical Atmosphere to Hectopascal?

To convert Technical Atmosphere to Hectopascal, enter the value in Technical Atmosphere in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our pressure converter page to convert between other units in this category.

Learn more →

What is the conversion factor from Technical Atmosphere to Hectopascal?

The conversion factor depends on the specific relationship between Technical Atmosphere and Hectopascal. You can find the exact conversion formula and factor on this page. Our calculator handles all calculations automatically. See the conversion table above for common values.

Can I convert Hectopascal back to Technical Atmosphere?

Yes! You can easily convert Hectopascal back to Technical Atmosphere by using the swap button (⇌) in the calculator above, or by visiting our Hectopascal to Technical Atmosphere converter page. You can also explore other pressure conversions on our category page.

Learn more →

What are common uses for Technical Atmosphere and Hectopascal?

Technical Atmosphere and Hectopascal are both standard units used in pressure measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our pressure converter for more conversion options.

For more pressure conversion questions, visit our FAQ page or explore our conversion guides.

Helpful Conversion Guides

Learn more about unit conversion with our comprehensive guides:

📚 How to Convert Units

Step-by-step guide to unit conversion with practical examples.

🔢 Conversion Formulas

Essential formulas for pressure and other conversions.

⚖️ Metric vs Imperial

Understand the differences between measurement systems.

⚠️ Common Mistakes

Learn about frequent errors and how to avoid them.

View All Guides →

All Pressure Conversions

Pascal to KilopascalPascal to MegapascalPascal to HectopascalPascal to BarPascal to MillibarPascal to AtmospherePascal to Technical AtmospherePascal to TorrPascal to Millimeter of MercuryPascal to Inch of MercuryPascal to Pound per Square InchPascal to Kilopound per Square InchPascal to Kilogram-force per Square CentimeterPascal to Kilogram-force per Square MeterPascal to Millimeter of Water ColumnPascal to Inch of Water ColumnKilopascal to PascalKilopascal to MegapascalKilopascal to HectopascalKilopascal to BarKilopascal to MillibarKilopascal to AtmosphereKilopascal to Technical AtmosphereKilopascal to TorrKilopascal to Millimeter of MercuryKilopascal to Inch of MercuryKilopascal to Pound per Square InchKilopascal to Kilopound per Square InchKilopascal to Kilogram-force per Square CentimeterKilopascal to Kilogram-force per Square MeterKilopascal to Millimeter of Water ColumnKilopascal to Inch of Water ColumnMegapascal to PascalMegapascal to KilopascalMegapascal to HectopascalMegapascal to BarMegapascal to MillibarMegapascal to AtmosphereMegapascal to Technical AtmosphereMegapascal to TorrMegapascal to Millimeter of MercuryMegapascal to Inch of MercuryMegapascal to Pound per Square InchMegapascal to Kilopound per Square InchMegapascal to Kilogram-force per Square CentimeterMegapascal to Kilogram-force per Square MeterMegapascal to Millimeter of Water ColumnMegapascal to Inch of Water ColumnHectopascal to PascalHectopascal to KilopascalHectopascal to MegapascalHectopascal to BarHectopascal to MillibarHectopascal to AtmosphereHectopascal to Technical AtmosphereHectopascal to TorrHectopascal to Millimeter of MercuryHectopascal to Inch of MercuryHectopascal to Pound per Square InchHectopascal to Kilopound per Square InchHectopascal to Kilogram-force per Square CentimeterHectopascal to Kilogram-force per Square MeterHectopascal to Millimeter of Water ColumnHectopascal to Inch of Water ColumnBar to PascalBar to KilopascalBar to MegapascalBar to HectopascalBar to MillibarBar to AtmosphereBar to Technical AtmosphereBar to TorrBar to Millimeter of MercuryBar to Inch of MercuryBar to Pound per Square InchBar to Kilopound per Square InchBar to Kilogram-force per Square CentimeterBar to Kilogram-force per Square MeterBar to Millimeter of Water ColumnBar to Inch of Water ColumnMillibar to PascalMillibar to KilopascalMillibar to MegapascalMillibar to HectopascalMillibar to BarMillibar to AtmosphereMillibar to Technical AtmosphereMillibar to TorrMillibar to Millimeter of MercuryMillibar to Inch of MercuryMillibar to Pound per Square InchMillibar to Kilopound per Square InchMillibar to Kilogram-force per Square CentimeterMillibar to Kilogram-force per Square MeterMillibar to Millimeter of Water ColumnMillibar to Inch of Water ColumnAtmosphere to PascalAtmosphere to KilopascalAtmosphere to MegapascalAtmosphere to HectopascalAtmosphere to BarAtmosphere to MillibarAtmosphere to Technical AtmosphereAtmosphere to TorrAtmosphere to Millimeter of MercuryAtmosphere to Inch of MercuryAtmosphere to Pound per Square InchAtmosphere to Kilopound per Square InchAtmosphere to Kilogram-force per Square CentimeterAtmosphere to Kilogram-force per Square MeterAtmosphere to Millimeter of Water ColumnAtmosphere to Inch of Water ColumnTechnical Atmosphere to PascalTechnical Atmosphere to KilopascalTechnical Atmosphere to MegapascalTechnical Atmosphere to BarTechnical Atmosphere to MillibarTechnical Atmosphere to AtmosphereTechnical Atmosphere to TorrTechnical Atmosphere to Millimeter of Mercury

Other Pressure Units and Conversions

Explore other pressure units and their conversion options:

View all pressure units →

Verified Against Authority Standards

All conversion formulas have been verified against international standards and authoritative sources to ensure maximum accuracy and reliability.

NIST Reference on Constants, Units and Uncertainty

National Institute of Standards and Technology — Fundamental physical constants and unit conversions

BIPM SI Units

Bureau International des Poids et Mesures — International System of Units (SI) definitions and standards

ISO 80000

International Organization for Standardization — Quantities and units international standards series

Last verified: February 19, 2026