Convert Atmospheres to Decibars

Formula

dbar = atm × 10.1325

Derivation from SI units:

• 1 atm = 101 325 Pa (exact, by definition)
• 1 dbar = 10⁻¹ bar = 10⁴ Pa
• 1 atm = 101325 Pa ÷ 10000 Pa per dbar = 10.1325 dbar

Both units are defined exactly, so the factor is exact. Atmosphere definition: atmosphere; Decibar definition: decibar.

Worked examples

1. A reading of 1.5 atm converts to 15.19875 dbar.
   1.5 atm × 10.1325 = 15.19875 dbar
2. A value of 10 atm is 101.325 dbar.
   10 atm × 10.1325 = 101.325 dbar

Where it's used

Atmospheres are used for chemistry and gas laws (STP and NTP conditions), while decibars appear in oceanography: CTD instruments report sea pressure in dbar. Both measure pressure, stress and differential pressure (force per unit area), so the conversion is a fixed factor.

Atmosphere to other pressure units

Frequently asked questions

Sources

• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "atmosphere, standard (atm)".
• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "bar", with SI prefix deci (10⁻¹).

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.