Pascals (Pa)
0
Equivalent pressure
Accurate conversion between atmospheres (atm) and pascals (Pa)
Convert atmospheres to pascals instantly with precise calculations for 2026. Includes reverse Pa to atm conversion, kPa, MPa, bar, psi, torr, full formula reference, and pressure conversion tables.
Professional pressure conversion for science, engineering, meteorology, and industrial applications
Convert standard atmospheres (atm) to pascals (Pa) using the exact defined value: 1 atm = 101,325 Pa. One standard atmosphere is the pressure exerted by a 760 mm column of mercury at sea level and 0°C. Our tool outputs Pa, kPa, MPa, bar, psi, and torr simultaneously, giving you a complete multi-unit pressure breakdown in a single step.
Switch seamlessly between atm → Pa and Pa → atm conversion modes. Whether you are reading atmospheric pressure data, working with gas laws, or converting a pressure rating from technical datasheets, both directions are handled instantly from a single input. No manual calculation or unit-factor memorisation needed.
Essential for physics and chemistry laboratories, meteorology, HVAC and mechanical engineering, scuba diving, aviation, automotive tyre pressure, and industrial gas systems. Correct pressure conversion is critical anywhere the SI unit Pascal must relate to the commonly used atmosphere unit in 2026 standards.
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The standard atmosphere (atm) is a unit of pressure defined as exactly 101,325 pascals. It was originally defined as the average atmospheric pressure at sea level on Earth. Although not an SI unit, the atmosphere remains widely used in chemistry, physics, scuba diving, and everyday weather discussion. When converting atmospheres to pascals, the relationship is exact and defined — making the conversion perfectly precise with no rounding error involved.
The pascal (Pa) is the SI derived unit of pressure, equal to one newton per square metre (N/m²). It is named after the French mathematician and physicist Blaise Pascal. Because 1 Pa is a very small pressure unit, kilopascals (kPa) and megapascals (MPa) are frequently used in engineering applications. Understanding how to convert atmospheres to pascals is fundamental to gas law calculations, pressure gauge readings, and international scientific reporting in 2026.
1 standard atmosphere = 101,325 Pa (exact, by definition)
| Atmospheres (atm) | Pascals (Pa) | Kilopascals (kPa) | Bar | PSI | Torr (mmHg) |
|---|---|---|---|---|---|
| 0.1 atm | 10,132.5 Pa | 10.133 kPa | 0.10133 bar | 1.4696 psi | 76 Torr |
| 0.25 atm | 25,331.25 Pa | 25.331 kPa | 0.25331 bar | 3.674 psi | 190 Torr |
| 0.5 atm | 50,662.5 Pa | 50.663 kPa | 0.50663 bar | 7.348 psi | 380 Torr |
| 0.75 atm | 75,993.75 Pa | 75.994 kPa | 0.75994 bar | 11.022 psi | 570 Torr |
| 1 atm | 101,325 Pa | 101.325 kPa | 1.01325 bar | 14.696 psi | 760 Torr |
| 1.5 atm | 151,987.5 Pa | 151.988 kPa | 1.51988 bar | 22.044 psi | 1,140 Torr |
| 2 atm | 202,650 Pa | 202.65 kPa | 2.0265 bar | 29.392 psi | 1,520 Torr |
| 3 atm | 303,975 Pa | 303.975 kPa | 3.03975 bar | 44.088 psi | 2,280 Torr |
| 5 atm | 506,625 Pa | 506.625 kPa | 5.06625 bar | 73.48 psi | 3,800 Torr |
| 10 atm | 1,013,250 Pa | 1,013.25 kPa | 10.1325 bar | 146.96 psi | 7,600 Torr |
| 20 atm | 2,026,500 Pa | 2,026.5 kPa | 20.265 bar | 293.92 psi | 15,200 Torr |
| 50 atm | 5,066,250 Pa | 5,066.25 kPa | 50.6625 bar | 734.8 psi | 38,000 Torr |
| 100 atm | 10,132,500 Pa | 10,132.5 kPa | 101.325 bar | 1,469.6 psi | 76,000 Torr |
1 atm = 101,325 Pa is an exact, defined value — not an approximation. This was established by the International Union of Pure and Applied Chemistry (IUPAC) and is used in all scientific and engineering calculations worldwide.
The pascal is the official SI derived unit for pressure, approved by the General Conference on Weights and Measures. Despite this, the atmosphere unit persists in many fields because 1 atm conveniently represents everyday ambient pressure at Earth's surface.
1 bar = 100,000 Pa, while 1 atm = 101,325 Pa. They are close but not equal — the bar is exactly 100 kPa and is widely used in meteorology and industry, whereas the standard atmosphere is the historical reference pressure for thermodynamic standard states.
1 atm = 101,325 Pa = 101.325 kPa = 1.01325 bar = 14.6959 psi = 760 Torr = 29.9213 inHg
For quick mental estimation: 1 atm ≈ 100 kPa (within 1.3%). This approximation is acceptable for most engineering estimates but use the exact value for scientific calculations.
Converting atmospheres to pascals is straightforward using the exact conversion factor. Follow these steps for accurate results every time:
STP (Standard Temperature and Pressure) as defined by IUPAC since 1982 is 0°C (273.15 K) and 100,000 Pa (1 bar) — not 1 atm. However, many older texts and engineering standards still use 1 atm (101,325 Pa) as the standard pressure reference. Always check which definition applies to your field when using tabulated gas data.
A common error is confusing atm with bar — they differ by 1,325 Pa (about 1.3%). Another mistake is using 100,000 Pa for 1 atm (that is 1 bar). Always use the exact factor of 101,325 Pa per atm for scientific and engineering accuracy. Also note that gauge pressure (psig, barg) is measured relative to ambient — convert to absolute pressure before applying the atm-to-Pa formula.
The atm to Pa conversion appears across a wide range of disciplines. In chemistry, the ideal gas law PV = nRT uses pressure in Pa (SI) or atm depending on the R value chosen (8.314 J/mol·K for Pa, or 0.08206 L·atm/mol·K for atm). In meteorology, surface pressure of about 1 atm is reported in hPa or mbar — 1 hPa = 100 Pa, so standard pressure = 1013.25 hPa. You can also use our BTU to Joules converter for related energy unit conversions in thermodynamics problems.
In scuba diving, pressure increases by roughly 1 atm for every 10 metres of water depth, so a diver at 30 m experiences approximately 4 atm (404,000 Pa) of absolute pressure. In automotive and industrial settings, tyre pressure (~2–3 bar), hydraulic systems, and gas storage cylinders are all specified in units that require converting to or from pascals for engineering compliance. For area-based unit needs in related projects, see our acres to square metres converter.
The National Institute of Standards and Technology provides authoritative definitions of the pascal, atmosphere, and all related pressure units used in scientific and industrial measurement.
Visit NIST →The International Union of Pure and Applied Chemistry defines standard pressure as 100 kPa (1 bar) for thermodynamic tables, while 1 atm = 101,325 Pa remains the standard atmosphere definition.
Our atm to Pa Tool →Explore our full library of free unit conversion tools for pressure, energy, area, time, and more. All tools are updated for 2026 standards and optimised for mobile use.
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