🌡️ mm (Hg) → atm Converter
Treat “mm” as shorthand for millimeters of mercury and convert to atmospheres.
Some legacy gauges and specifications abbreviate millimeters of mercury as just “mm.” This converter interprets those readings correctly and expresses the pressure in atmospheres.
Atmospheres: 1 atm
Kilopascals: 101.325 kPa
How to Use This Calculator
Enter mm (Hg)
Type the pressure reading labeled only as “mm” from older gauges or documentation.
View atmospheres
The value is divided by 760 to compute atmospheres.
Check kPa
Kilopascals provide an SI-compatible reference for the same pressure.
Formula
Atmospheres = mm ÷ 760
Kilopascals ≈ mm × 0.133322
Use the formula breakdown to confirm the calculation logic or perform the conversion manually if needed.
Full Description
In some industries, especially legacy vacuum systems, millimeters of mercury are abbreviated simply as “mm.” This tool removes ambiguity by translating those readings into atmospheres and kilopascals, the more widely recognized standards.
Because the conversion assumes millimeters of mercury, it preserves compatibility with modern pressure documentation while honoring legacy data.
Frequently Asked Questions
Is “mm” the same as mmHg?
In many older documents, yes. This converter treats mm as millimeters of mercury.
What happens if the value is already mmHg?
The result matches a standard mmHg-to-atm conversion; the page simply tolerates the shorthand.
Can I add other outputs?
Extend the page to include psi, bar, or other units as needed.
Is the conversion temperature-dependent?
The standard factor assumes 0 °C. Adjustments for temperature are rarely required outside high-precision contexts.