inches of mercury to mm of water
Convert inch of mercury to mm of water — instant, free, with the formula shown.
How to convert inch of mercury to mm of water
To convert inch of mercury to mm of water, multiply by 345.31557668:
For example, 10 inHg × 345.315577 = 3453.155767 mmH₂O.
inHg to mmH₂O conversion table
| inches of mercury (inHg) | mm of water (mmH₂O) |
|---|---|
| 1 inHg | 345.315577 mmH₂O |
| 2 inHg | 690.631153 mmH₂O |
| 5 inHg | 1726.577883 mmH₂O |
| 10 inHg | 3453.155767 mmH₂O |
| 25 inHg | 8632.889417 mmH₂O |
| 50 inHg | 17265.778834 mmH₂O |
| 100 inHg | 34531.557668 mmH₂O |
| 250 inHg | 86328.894169 mmH₂O |
| 500 inHg | 172657.788338 mmH₂O |
| 1000 inHg | 345315.576675 mmH₂O |
Other inch of mercury conversions
Convert to mm of water from another unit
inHg to mmH₂O — frequently asked
How many mm of water are in 1 inch of mercury?
1 inch of mercury = 345.315577 mm of water (inHg × 345.315577 = mmH₂O).
What is the formula to convert inch of mercury to mm of water?
Multiply your inch of mercury value by 345.31557668 to get mm of water.
How do I convert 10 inches of mercury to mm of water?
10 inHg = 3453.155767 mmH₂O. For 100 inHg the answer is 34531.557668 mmH₂O. Use the calculator on this page for any other value.
When to convert inch of mercury to mm of water
Pressure conversion — common questions
What's the difference between bar and psi?
1 bar = 100,000 Pa ≈ 14.504 psi. Bar is metric/SI-friendly; psi is US imperial. Tire pressure in cars is commonly 30–35 psi or ≈ 2.1–2.4 bar.
Is 1 atmosphere the same as 1 bar?
Very close but not identical. 1 atm = 1.01325 bar = 101,325 Pa. 1 bar = 100,000 Pa.
Why is blood pressure in mmHg?
Historically measured with mercury manometers — the pressure that supports a column of mercury that many millimetres tall. 120 mmHg systolic ≈ 16 kPa.