Convert Decibars to Millimeters of Mercury

Formula

mmHg = dbar × 75.00615758457

Derivation from SI units:

• 1 dbar = 10⁻¹ bar = 10⁴ Pa
• 1 mmHg = 13 595.1 kg/m³ × 9.80665 m/s² × 0.001 m = 133.322387415 Pa
• 1 dbar = 10000 Pa ÷ 133.322387415 Pa per mmHg = 75.00615758457 mmHg

Both units are defined exactly, so the factor is exact. Decibar definition: decibar; Millimeter of Mercury definition: millimeter of mercury.

Worked examples

1. A reading of 50 dbar converts to 3750.307879 mmHg.
   50 dbar × 75.00615758 = 3750.307879 mmHg
2. A value of 1000 dbar is 75006.15758 mmHg.
   1000 dbar × 75.00615758 = 75006.15758 mmHg

Where it's used

Decibars are used for oceanography: CTD instruments report sea pressure in dbar, while millimeters of mercury appear in blood pressure (e.g. 120/80 mmHg). Both measure pressure, stress and differential pressure (force per unit area), so the conversion is a fixed factor.

Decibar 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, "bar", with SI prefix deci (10⁻¹).
• 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, "millimeter of mercury, conventional (mmHg)".

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