30 inhg is equal to approximately 1015.92 hpa.
To convert inches of mercury (inhg) to hectopascals (hpa), you multiply the inhg value by 33.8639. This conversion is based on the pressure equivalence between these units used in meteorology and aviation.
Conversion Tool
Result in hpa:
Conversion Formula
The formula to convert inches of mercury (inhg) to hectopascals (hpa) is:
hpa = inhg × 33.8639
This works because 1 inch of mercury corresponds to 33.8639 hectopascals. The inch of mercury is a unit of pressure based on the height of a mercury column, whereas hectopascal is a metric unit representing pressure in Pascals multiplied by 100.
Example calculation for 30 inhg:
- Start with 30 inhg.
- Multiply 30 by 33.8639.
- 30 × 33.8639 = 1015.917 hpa.
- So, 30 inhg equals approximately 1015.92 hpa.
Conversion Example
- Convert 25 inhg to hpa:
- Multiply 25 by 33.8639.
- 25 × 33.8639 = 846.5975 hpa.
- Result is about 846.60 hpa.
- Convert 40 inhg to hpa:
- Multiply 40 by 33.8639.
- 40 × 33.8639 = 1354.556 hpa.
- Result is about 1354.56 hpa.
- Convert 10 inhg to hpa:
- Multiply 10 by 33.8639.
- 10 × 33.8639 = 338.639 hpa.
- Result is about 338.64 hpa.
- Convert 50 inhg to hpa:
- Multiply 50 by 33.8639.
- 50 × 33.8639 = 1693.195 hpa.
- Result is about 1693.20 hpa.
Conversion Chart
| inhg | hpa |
|---|---|
| 5.0 | 169.32 |
| 10.0 | 338.64 |
| 15.0 | 507.96 |
| 20.0 | 677.28 |
| 25.0 | 846.60 |
| 30.0 | 1015.92 |
| 35.0 | 1185.23 |
| 40.0 | 1354.56 |
| 45.0 | 1523.88 |
| 50.0 | 1693.20 |
| 55.0 | 1862.54 |
This chart shows the equivalent hpa values for inhg values from 5.0 to 55.0. Use it to quickly find the hpa reading by matching the inhg value on the left, the right column shows the pressure in hectopascals.
Related Conversion Questions
- What is the hpa equivalent of 30 inches of mercury in weather reports?
- How do I convert 30 inhg to hpa for aviation pressure settings?
- Is 30 inhg considered high or low pressure in hpa?
- What’s the formula to change 30 inhg into hectopascals?
- How many hectopascals equal 30 inhg in metric units?
- Can I use 30 inhg to hpa conversion for barometric pressure readings?
- Why does 30 inhg equal about 1016 hpa on the pressure scale?
Conversion Definitions
inhg: Inches of mercury (inhg) is a unit measuring pressure by the height in inches of a mercury column. It’s used mainly in weather reports and aviation to express atmospheric pressure, based on how mercury responds to force exerted by the air.
hpa: Hectopascal (hpa) is a unit of pressure equal to 100 Pascals. It’s widely used meteorology to quantify atmospheric pressure, replacing older units. The hpa provides a metric standard that is easier to use with SI units and instruments.
Conversion FAQs
Why is the conversion factor 33.8639 used between inhg and hpa?
The factor 33.8639 comes from the physical properties of mercury and the definition of pressure units. One inch of mercury column exerts a pressure equivalent to 33.8639 hpa due to mercury’s density and gravity. This constant lets people convert pressure measurements accurately.
Does temperature affect the conversion from inhg to hpa?
Temperature can slightly influence the density of mercury and air, but for standard atmospheric pressure conversions, the effect is negligible. The factor 33.8639 assumes standard temperature and gravity, so minor temperature variations won’t cause meaningful errors in typical pressure conversions.
Can I convert inhg to hpa without a calculator?
While possible by approximations, it’s hard to do quickly without a calculator because the factor 33.8639 is not a simple number. For rough estimates, you can use 34 as a multiplier, but for precise results, a calculator or conversion tool is recommended.
Why do pilots prefer inhg but meteorologists use hpa?
Pilots in the US use inhg because many aviation instruments and systems are designed with imperial units. Meteorologists use hpa internationally because it aligns with the SI system and is easier to integrate with other metric measurements and international data sharing.
Is there a direct physical measurement for both inhg and hpa?
Inhg is based on the height of mercury in a column, a direct physical measurement. Hpa is a derived SI unit based on force per area, related to Pascals. Both relate to pressure but are measured differently; inhg is tactile, hpa is calculated from force and area.