Convert Pressure from hectopascals to torr (hPa to torr)

hectopascal to torr Conversion Formula

Example

Let's convert 5 hectopascal (hPa) to torr (torr).

Using the formula:

Therefore, 5 hectopascal (hPa) is equal to 3.750308413520848754 torr (torr).

How many hectopascals are in one torr? One torr (torr) contains 1.3332236842105263158 hectopascals (hPa) — the inverse of the factor above. Multiplying by 0.7500616827041697508 takes you from hectopascals to torr; multiplying by 1.3332236842105263158 brings you back.

Put in words: one hectopascal equals 0.7500616827041697508 torr, so the hectopascal is the smaller unit of this pair. Converting between them never changes the amount of pressure being measured — only the size of the unit you count it in.

What is a hectopascal (hPa)?

A hectopascal (hPa) is a metric unit used to measure pressure.

You will most commonly see it in weather reports to describe atmospheric pressure (also known as barometric pressure).

Hectopascal vs. Millibar: Which is it?

If you've seen millibars (mbar) on older weather maps, the hectopascal is its modern replacement.

The switch was simple for meteorologists because the units are exactly the same (1 hPa = 1 mbar).

The hectopascal is now the international standard for measuring atmospheric pressure, making weather data consistent worldwide.

How to Convert Hectopascals to Pascals (hPa to Pa)

The conversion is in the name. The prefix "hecto-" means 100. This makes the math simple:

• 1 hectopascal (hPa) = 100 pascals (Pa)

How to Convert Hectopascals to Kilopascals (hPa to kPa)

Just as "hecto-" means 100, "kilo-" means 1,000. This defines their relationship:

• 1 hectopascal (hPa) = 0.1 kilopascals (kPa)
• 10 hectopascals (hPa) = 1 kilopascal (kPa)

What Is a Torr?

A torr (Torr) is a unit of pressure.

It is primarily used to measure a vacuum, or pressures much lower than the air pressure we experience every day.

While the modern standard (SI) unit for pressure is the pascal (Pa), the torr is still widely used in many scientific and engineering fields.

For conversion, one torr is equal to about 133.32 pascals.

A much simpler way to think about it is in relation to our atmosphere: one standard atmosphere (atm) is defined as exactly 760 Torr.

Where Did the Torr Come From?

The unit is named in honor of Evangelista Torricelli, the 17th-century Italian physicist who invented the mercury barometer.

Because of this, one torr was initially defined as being equal to one millimeter of mercury (mmHg).

This means 1 Torr is the pressure exerted by a column of mercury that is one millimeter high.

Torr vs. Atmosphere (atm)

As mentioned, the torr's most convenient relationship is with the standard atmosphere (atm).

One standard atmosphere—the average air pressure at sea level—is set at exactly 760 Torr.

This straightforward, whole-number conversion makes the torr a popular choice for anyone working with fractions of atmospheric pressure.

Where Is the Torr Used Today?

The torr is the primary unit of measurement for high-vacuum and ultra-high-vacuum technology.

Because it is such a small unit (it takes 760 of them to equal one atmosphere), it is ideal for quantifying pressures far below normal air pressure.

You will find the torr used in many advanced scientific and industrial fields, including:

• Semiconductor manufacturing
• Thin-film deposition (like adding anti-reflective coatings to glasses)
• Mass spectrometry
• Particle accelerators
• Vacuum furnaces

hectopascal to torr Conversion Table

Here are some quick reference conversions from hectopascal (hPa) to torr (torr):