inHg to mmHg Converter
One inHg equals 25.40000362 mmHg (1 inHg = 25.40000362 mmHg). Multiply a inHg value by 25.40000362 to get the equivalent in mmHg. Use the calculator above for instant results, or follow the formula, worked examples, and reference table below.
Formula
mmHg = inHg × 25.40000362
Multiply the inHg value by 25.40000362 to get the equivalent value in mmHg.
Example Conversions
1 inHg (inHg)
25.40000362 mmHg (mmHg)
5 inHg (inHg)
127.0000181 mmHg (mmHg)
10 inHg (inHg)
254.0000362 mmHg (mmHg)
25 inHg (inHg)
635.0000905 mmHg (mmHg)
100 inHg (inHg)
2540.000362 mmHg (mmHg)
Conversion Table
| inHg (inHg) | mmHg (mmHg) |
|---|---|
| 0.1 | 2.540000362 |
| 0.5 | 12.70000181 |
| 1 | 25.40000362 |
| 2 | 50.80000724 |
| 5 | 127.0000181 |
| 10 | 254.0000362 |
| 25 | 635.0000905 |
| 50 | 1270.000181 |
| 100 | 2540.000362 |
| 250 | 6350.000905 |
| 500 | 12700.00181 |
| 1000 | 25400.00362 |
How to Convert Manually
Use these steps to convert inHg values to mmHg without the calculator.
- Write down the value in inHg (inHg) that you want to convert.
- Multiply that value by 25.40000362.
- For example, 10 inHg × 25.40000362 = 254.0000362 mmHg.
- Label the result as mmHg (mmHg).
Relative Size Comparison
This chart shows the visual difference in size between exactly one inHg and one mmHg.
About inHg and mmHg
The inch of mercury is about 3,386.39 pascals. US weather reports and aviation altimeter settings quote barometric pressure in inches of mercury. The millimeter of mercury is about 133.322 pascals — the height a pressure pushes a mercury column. Blood pressure worldwide is still reported in mmHg. One inHg equals 25.40000362 mmHg (1 inHg = 25.40000362 mmHg). inHg to mmHg conversion comes up most often in US barometric weather reports and in aviation altimeter settings, typically when figures need restating for blood pressure readings.
Precision and Rounding: Several pressure factors are exact by definition (1 atm = 101,325 Pa; 1 bar = 100,000 Pa) while others, like psi and mmHg, are derived and carry long decimals. Tire and weather readings tolerate whole-number rounding; calibration, medicine, and process engineering need the full factor before rounding.
Conversion factors per NIST Special Publication 811 and the BIPM SI Brochure (9th edition) (reference).
Worked Example
15 inHg equals 381.0000543 mmHg.
15 inHg × 25.40000362 = 381.0000543 mmHg
FAQ
How do I convert inHg to mmHg?
Multiply the inHg value by 25.40000362 to get the equivalent value in mmHg.
What is the formula for inHg to mmHg?
The formula is mmHg = inHg × 25.40000362.
How many mmHg are in 1 inHg?
1 inHg equals 25.40000362 mmHg.
Can I convert mmHg back to inHg?
Yes. 1 mmHg equals 0.03937007313 inHg, and the related converter can reverse the calculation.
What are common names for inHg and mmHg?
inHg is shown as inHg and may also be searched as inches of mercury, in Hg. mmHg is shown as mmHg and may also be searched as millimeters of mercury, mm Hg.
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