Gigapascals to Pascals (GPa to Pa)

1 gigapascal equals 1,000,000,000 pascals exactly.

1 gigapascal = 1,000,000,000 pascals

How to convert gigapascals to pascals

To convert gigapascals to pascals, multiply the number of gigapascals by 1,000,000,000. This factor is exact. To go the other way, multiply pascals by 1×10⁻⁹.

pascals = gigapascals × 1,000,000,000

Example: 10 gigapascals = 10,000,000,000 pascals.

About these units

Gigapascal (GPa)

Metric (SI)Current unit

One billion pascals. Used for the stiffness (Young's modulus) of materials; steel is about 200 GPa.

Blaise Pascal's name was attached to the SI unit of pressure in 1971, when the 14th General Conference on Weights and Measures adopted it for one newton per square metre. A gigapascal is a billion of them, 10^9 Pa, which is a size that makes sense only for solid materials and deep-Earth conditions, not for weather or tyres.

Materials scientists quote stiffness in it. Wikipedia's table of Young's modulus lists structural steel at about 200 GPa and diamond at 1,220 GPa, while geophysicists use gigapascals for tectonic stresses and pressures inside the planet. Atmospheric pressure of about 101,325 Pa is therefore about 0.0001 GPa, and one gigapascal is roughly 145,000 psi or 145 ksi. A gigapascal also equals one thousand megapascals, the unit in which concrete and steel strengths are usually written.

1 gigapascal = 1,000,000,000 pascals (exactly).

Sources: Wikipedia: Pascal (unit); Wikipedia: Pounds per square inch

Pascal (Pa)

Metric (SI)Current unit

The SI unit of pressure: one newton per square meter. A very small unit; atmospheric pressure is about 101,325 Pa.

Blaise Pascal never saw a pascal, because the name was adopted by the 14th CGPM in 1971 for the newton per square meter. He did, however, earn the honor. In 1647 he published experiments on the vacuum, and on 19 September 1648 his brother-in-law Florin Périer carried a mercury barometer up the Puy de Dôme near Clermont, where the column stood at about 23 inches against about 26 at the base. Pascal had reasoned that air pressure should fall with altitude, and the result confirmed it.

One pascal is a tiny pressure, so the unit is mostly met with prefixes. Standard atmospheric pressure is 101,325 Pa, a typical sea-level reading is about 1,013 hPa, and the threshold of hearing in air is taken as a reference pressure of 20 micropascals. Building airtightness tests, in contrast, are run at 50 Pa.

Pascal is also remembered for hydrostatics, where he showed that pressure depends on height difference rather than the weight of the fluid, and for the hydraulic press.

The pascal is the reference unit for pressure on this site.

Sources: Wikipedia: Pascal (unit); Wikipedia: Blaise Pascal

Related conversions

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