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hPa to atm converter

1 hectopascal equals 0.0009869233 standard atmospheres. Conversions use atm = hPa × 0.000987

hPa → 0.0009869233 atm

atm = hPa × 0.000987

Converter

Worked examples

1 hPa = 0.0009869233 atm
2 hPa = 0.0019738465 atm
5 hPa = 0.0049346163 atm
10 hPa = 0.0098692327 atm
100 hPa = 0.09869233 atm

hectopascals to standard atmospheres conversion table

hPa	atm	Arithmetic
1 hPa	0.0009869233 atm	× 0.000987
2 hPa	0.0019738465 atm	× 0.000987
3 hPa	0.0029607698 atm	× 0.000987
4 hPa	0.0039476931 atm	× 0.000987
5 hPa	0.0049346163 atm	× 0.000987
6 hPa	0.0059215396 atm	× 0.000987
8 hPa	0.0078953861 atm	× 0.000987
10 hPa	0.0098692327 atm	× 0.000987
12 hPa	0.01184308 atm	× 0.000987
15 hPa	0.01480385 atm	× 0.000987
20 hPa	0.01973847 atm	× 0.000987
25 hPa	0.02467308 atm	× 0.000987
30 hPa	0.0296077 atm	× 0.000987
40 hPa	0.03947693 atm	× 0.000987
50 hPa	0.04934616 atm	× 0.000987
60 hPa	0.0592154 atm	× 0.000987
70 hPa	0.06908463 atm	× 0.000987
80 hPa	0.07895386 atm	× 0.000987
90 hPa	0.08882309 atm	× 0.000987
100 hPa	0.09869233 atm	× 0.000987

How to convert hPa to atm

Take your value in hectopascals.
Multiply by 0.000987
That is your answer in standard atmospheres — no rounding needed until you choose a display precision.

atm to hPa kPa to atm bar to atm psi to atm atm to kPa atm to bar atm to psi atm to mmHg atm to inHg all pressure units

Questions

How many standard atmospheres in 1 hectopascal?

Exactly 0.0009869233 atm. The factor follows from the definitions of both units, not from a measurement, so it is exact.

How do I convert hPa to atm?

Multiply the hectopascals figure by 0.000987 — or use the converter above, which updates as you type.

Is hPa to atm the same as atm to hPa?

No — they are inverses. One hPa is 0.0009869233 atm, while one atm is 1,013.25 hPa.

What is 1 hPa in atm?

1 hPa = 0.0009869233 atm (see the value page for the full arithmetic).