21 Pascals to Standard Atmospheres

21 Pa ≈ 0.00020725 atm

Calculation: atm = 21 Pa × 9.86923 × 10⁻⁶ ≈ 0.00020725 atm

Pascal to Standard Atmosphere Converter

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How much pressure is 21 Pa?

0.003 psi (0.021 kPa) is comparable to a laboratory vacuum, such as inside a glass bell jar.

What does 21 Pa look like?

Illustration of a vacuum bell jar
0.003 psi (0.021 kPa) is comparable to a laboratory vacuum, such as inside a glass bell jar.

How to Convert Pascal to Standard Atmosphere

1 pascal = 9.86923 × 10-6 standard atmospheres exact

Standard Atmosphere = Pascal × 9.86923 × 10-6

Example: 21 Pa × 9.86923 × 10-6 = 0.00020725 atm

Reverse Conversion

To convert standard atmospheres back to pascals:

  • Remember, 1 standard atmosphere equals 101325 pascals.
  • To convert 0.00020725 atm to Pa, multiply 0.00020725 x 101325, resulting in 21 Pa.

exact This conversion factor is exact by international definition.

21 Pa is also equal to:

  • 0.021 kPa
  • 0.00021 bar
  • 0.0030458 psi
About these units

Pascal: SI derived unit of pressure equal to one newton per square meter (N/m²).

Standard atmosphere: Standard unit of atmospheric pressure defined as exactly 101,325 pascals.

Frequently Asked Questions

How much is 21 pascals in standard atmospheres?

21 pascals equals 0.00020725 standard atmospheres. This is calculated by multiplying 21 by the conversion factor 9.86923 × 10⁻⁶.

What does 21 pascals look like in standard atmospheres?

21 pascals (0.00020725 standard atmospheres) is very low pressure — a gentle breeze creates about 1-10 Pa.

How do you calculate 21 pascals to standard atmospheres?

Multiply 21 by the conversion factor 9.86923 × 10⁻⁶. The calculation is 21 × 9.86923 × 10⁻⁶ = 0.00020725 standard atmospheres. This factor is defined by international measurement standards.

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21 pascals = 0.000207254 standard atmospheres
21 pascals = 0.000207254 standard atmospheres — conversion chart

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For general conversions between pascals and standard atmospheres, see the pascals to standard atmospheres converter.

Also convert Pascals to:

Conversion factors verified against NIST, BIPM, ISO 80000-4 1 atm = 101 325 Pa by definition (BIPM). Last reviewed: March 2026
Adilson Fernandes By Adilson Fernandes
Tiago Fernandes Reviewed by Tiago Fernandes

All unit conversions on CoolConversion use conversion factors defined or documented by internationally recognised standards bodies (such as ISO and NIST), including both SI and non-SI units.