How to Convert Atmospheres to Pascals (atm to Pa)
Pressure conversions are used for tyre pressure (psi or bar), blood pressure readings in mmHg and weather maps in millibars. This guide shows how to convert atmospheres into pascals by hand, with examples and a quick-reference table.
The conversion
To convert atmospheres to pascals, multiply the value by 101,325. To go the other way, divide by the same number (or multiply by 9.869233e-06). For a quick estimate, multiply by about 100,000.
Pascals = atmospheres × 101,325
Worked examples
- 3 atm = 303,975 Pa
- 12.5 atm = 1,266,562.5 Pa
- 75 atm = 7,599,375 Pa
Atmospheres to Pascals table
| Atmospheres | Pascals |
|---|---|
| 1 atm | 101,325 Pa |
| 2 atm | 202,650 Pa |
| 5 atm | 506,625 Pa |
| 10 atm | 1,013,250 Pa |
| 20 atm | 2,026,500 Pa |
| 25 atm | 2,533,125 Pa |
| 50 atm | 5,066,250 Pa |
| 100 atm | 10,132,500 Pa |
| 250 atm | 25,331,250 Pa |
| 500 atm | 50,662,500 Pa |
| 1,000 atm | 101,325,000 Pa |
Common questions
Is atm to Pa exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Pascals to Atmospheres converter.
Mistakes to avoid
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Background
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
Writing the units next to every number while you work is the simplest way to avoid mistakes. If the units do not cancel to leave the one you want, the calculation is set up wrongly.
Many conversion factors are exact by definition. The inch has been defined as exactly 2.54 centimetres since 1959, and the pound as exactly 0.45359237 kilograms, so conversions involving them can be as precise as you need.
For any value, use the Atmospheres to Pascals Converter or browse all pressure converters.
Run your own numbers: Atmospheres to Pascals Converter