Standard Atmospheres to Inches of Mercury Converter
1 standard atmosphere ≈ 29.9212528 inches of mercury
1 standard atmosphere equals 29.9213 inches of mercury
How to convert standard atmospheres to inches of mercury
Unit conversion preserves the pressure reference. Gauge pressure and absolute pressure are different readings; changing between them also needs the ambient pressure. Mercury and water-column units use the conventions stated in their unit notes.
inHg = atm × 29.92125276One standard atmosphere is 29.92125276 inches of mercury, so a single multiplication converts any value.
299.213 inHg ≈ 10 × 29.92125276Standard atmospheres to inches of mercury conversion table
Common values in standard atmospheres, converted to inches of mercury.
| Standard atmospheres (atm) | Inches of mercury (inHg) |
|---|---|
| 1 | 29.921253 |
| 2 | 59.842506 |
| 3 | 89.763758 |
| 4 | 119.68501 |
| 5 | 149.60626 |
| 10 | 299.21253 |
| 20 | 598.42506 |
| 25 | 748.03132 |
| 50 | 1,496.0626 |
| 100 | 2,992.1253 |
| 250 | 7,480.3132 |
| 500 | 14,960.626 |
| 1,000 | 29,921.253 |
About these units
standard atmosphereatm
Exactly 101,325 pascals, the defined standard sea-level pressure.
Reference: CGPM 1954.
inch of mercuryinHg
Exactly 25.4 mmHg. The US aviation and weather-report pressure unit.
Sources and precision
Table results are rounded to 8 significant digits; formula constants may be rounded to 10. Worked example answers use 6 significant digits. The converter starts at 6 significant digits and lets you change display precision. Calculations use the stored factors without intermediate rounding. Exact unit definitions do not make an input measurement more precise; conventional and measured factors follow the assumptions stated here.