How do you convert atmospheres to hectopascals?

To convert atmospheres (atm) to hectopascals (hPa), multiply the pressure in atmospheres by 1,013.25 (hectopascals = atmospheres × 1,013.25).

What is 5 atmospheres in hectopascals?

5 atmospheres (5 atm) is equal to 5,066.25 hectopascals (5,066.25 hPa).

Which is larger, 1 standard atmosphere (atm) or 1 hectopascal (hPa)?

One standard atmosphere (atm) is larger than one hectopascal (hPa). Specifically, 1 atm contains 1,013.25 hPa, whereas 1 hPa is 0.00098692 atm.

How do I convert back from hectopascals (hPa) to atmospheres (atm)?

To reverse the calculation from hPa to atm, multiply your hectopascal value by the inverse factor 0.00098692 (or divide by 1,013.25). You can also click the Swap button in the tool above to flip directions in one click.

How many decimal places should I round atm to hPa results to?

For everyday comparisons and quick estimates, rounding to 2 decimal places is usually sufficient (for example, 5 atm ≈ 5,066.25 hPa). For engineering, laboratory, or machining specifications, select 4 or 6 decimals—or Scientific (10ⁿ) mode—in the calculator toolbar above.

Atmospheres to Hectopascals Converter

Enter the pressure in atmospheres below to convert it to hectopascals.

Hectopascals to Atmospheres (hPa → atm)

Convert Atmospheres to Hectopascals

Enter a value in atmospheres (atm) to convert to hectopascals (hPa).

Value (atm)

From

Result

•

5,066.25hectopascals

5 atm = 5,066.25 hPa

Result updates automatically

Get Widget

Equivalent Measurements Across UnitsFor 5 atm

Pascals506,625 Pa

Kilopascals506.625 kPa

Bars5.06625 bar

PSI73.47974 psi

Suggested Conversions

Reference:NIST SP 811 (NIST SP 811 App. B.9 (Pressure & Stress))

[1–3] ↓

Standard Atmosphere to Hectopascal Conversion Table

Table showing various standard atmosphere measurements converted to hectopascals. Click any preset value or arrow to load it into the converter.

Atmospheres (atm)	Hectopascals (hPa)
1 atm	1,013.25 hPa
2 atm	2,026.5 hPa
2.5 atm	2,533.125 hPa
5 atm	5,066.25 hPa
10 atm	10,132.5 hPa
15 atm	15,198.75 hPa
20 atm	20,265 hPa
25 atm	25,331.25 hPa
30 atm	30,397.5 hPa
50 atm	50,662.5 hPa

How to Convert Atmospheres to Hectopascals

To convert atmospheres to hectopascals, multiply the pressure by the following conversion ratio: 1,013.25 hectopascals/standard atmosphere.

Since one standard atmosphere is equal to 1,013.25 hectopascals, you can use this simple formula to convert:

hectopascals = atmospheres × 1,013.25

The pressure in hectopascals is equal to the pressure in atmospheres multiplied by 1,013.25.

For example, here's how to convert 5 atmospheres to hectopascals using the formula above.

hectopascals = (5 atm × 1,013.25) = 5,066.25 hPa

How Many Hectopascals Are in a Standard Atmosphere?

There are 1,013.25 hectopascals in a standard atmosphere, which is why we use this value in the formula above.

1 atm = 1,013.25 hPa|1 hPa = 0.000986923 atm

Our standard atmosphere to hectopascal calculator automatically converts your pressure measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.

Atmospheres and hectopascals are both units used to measure pressure. Keep reading to learn more about each unit.

What Is a Standard Atmosphere?

A standard atmosphere is a unit of pressure equal to 101,325 pascals (Pa), the base unit for pressure. Standard sea-level atmospheric pressure defined as 101,325 Pascals. [1]

The standard atmosphere is classified as a standard unit of pressure. Atmospheres can be abbreviated as atm; for example, 1 standard atmosphere can be written as 1 atm.

When working with atmospheres (atm) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.

In practice, atmospheres (atm) are widely used across large-scale industrial, bulk, and macro-level pressure specifications within international standard workflows, engineering documentation, and technical data sheets.

Learn more about atmospheres in our Pressure Converter.

What Is a Hectopascal?

A hectopascal is a unit of pressure equal to 100 pascals (Pa), the base unit for pressure. Equal to 100 Pascals (identical to 1 millibar). [2]

The hectopascal is classified as a metric and SI-compatible unit of pressure. Hectopascals can be abbreviated as hPa; for example, 1 hectopascal can be written as 1 hPa.

In the metric system, "hecto" is the standard SI prefix for hundreds, or 10². This makes the hectopascal (hPa) a convenient decimal multiple of the pascal (Pa).

In practice, hectopascals (hPa) are widely used across standard pressure applications within SI metric workflows, engineering documentation, and technical data sheets.

Learn more about hectopascals in our Pressure Converter.

When converting pressure between atmospheres (atm) and hectopascals (hPa), keep full floating-point precision (1 atm = 1,013.25 hPa; 1 hPa = 0.000986923 atm) during intermediate calculations and round only the final hectopascal figure to match your instrument tolerance.

More Standard Atmosphere & Hectopascal Conversions

Need to calculate in the opposite direction? Use our hectopascals to atmospheres calculator to switch your starting unit immediately. You can also explore related tools such as converting hectopascals to atmospheres, converting pascals to hectopascals, or converting inches of mercury to hectopascals.

Convert from Atmospheres

Convert to Hectopascals

Frequently Asked Questions

There are 1,013.25 hectopascals (hPa) in 1 standard atmosphere (atm). Conversely, 1 hectopascal (hPa) is equal to 0.00098692 atmospheres (atm).

Pressure Converter

Quick Info

Direct Factor: 1 standard atmosphere (atm) equals 1,013.25 hectopascals (hPa).
Inverse Factor: 1 hectopascal (hPa) equals 0.00098692 atmospheres (atm).
Formula: hectopascals = atmospheres × 1,013.25.
Verified Precision: Anchored to official NIST SP 811 and ISO/IEC 80000 standards.

Units Comparison

Standard Atmosphere (atm)

Standard sea-level atmospheric pressure defined as 101,325 Pascals.

Hectopascal (hPa)

Equal to 100 Pascals (identical to 1 millibar).

Pascal (Pa)

SI derived unit of pressure equal to 1 Newton per square meter (N/m²).

References

[1]NIST SP 811 · NIST SP 811 App. B.9 (Pressure & Stress)
Source
[2]NIST CUU · Derived SI Unit: Pascal (Pa)
Source
[3]BIPM · SI Brochure (9th Ed.) — Mechanics
Source

Related Categories

Add This Calculator to Your Site

Free HTML widget · 4 embed formats

Embed the interactive Atmospheres to Hectopascals converter on your blog, classroom, or documentation page.

Customize & Get Embed Code

References

NIST · BIPM · ISO

[1]
NIST SP 811 (NIST SP 811 App. B.9 (Pressure & Stress))·Pressure Metrology Standard — Atmospheres (atm) to Hectopascals (hPa)
NIST SP 811 Standard
[2]
NIST CUU (Derived SI Unit: Pascal (Pa))·Unit Specifications: Standard Atmosphere (atm) & Hectopascal (hPa)
NIST CUU Specification
[3]
BIPM (SI Brochure (9th Ed.) — Mechanics)·Conversion Factors & Mathematical Basis (atm to hPa)
BIPM Reference

Measurement Navigator78 Categories9 Scientific Domains

Browse All 78 Measurement Categories

A–Z Directory →Sitemap

Common ConvertersEveryday metric, imperial, and US customary converters for length, weight, volume, temperature, area, pressure, energy, speed, time, and data.