This converter turns inches of mercury into megapascals instantly, using the exact factor 1 inch of mercury = 0.003386389 megapascals. Type any number and the result updates as you go — nothing is sent to a server, so the arithmetic happens entirely in your browser.
US aviation and weather altimeter setting unit. Used for material strength and hydraulic systems.
Because the relationship is a simple proportion, one multiplication does the whole job. The table further down gives pre-computed values for the amounts people look up most often, and the result panel also reports the reverse conversion so you can check the figure both ways.
The formula
inches of mercury- The amount you are converting, measured in inches of mercury
0.003386389- The exact number of megapascals in one inch of mercury
megapascals- The converted result
How it works, step by step
- Enter the number of inches of mercury you want to convert.
- The value is multiplied by 0.003386389, the exact conversion factor.
- The result is displayed in megapascals, rounded for readability.
- The unrounded value and the reverse conversion appear underneath so you can verify it.
Worked examples
Converting 5 inches of mercury
Multiply 5 by 0.003386389. That gives 0.016932 megapascals. A quick sanity check: one inch of mercury is smaller than one megapascal, so the number should get smaller — and it does.
Converting 72 inches of mercury
72 × 0.003386389 = 0.24382 megapascals. Working backwards, 0.24382 ÷ 0.003386389 returns 72 inches of mercury, which confirms the factor is applied the right way round.
How to read your score
Frequently asked questions
How many megapascals are in one inch of mercury?
Exactly 0.003386389. Every conversion on this page is that single number multiplied by your input, so the result carries no rounding error beyond what is shown.
What is the formula to convert inches of mercury to megapascals?
Megapascals = inches of mercury × 0.003386389. To reverse it, divide instead: inches of mercury = megapascals ÷ 0.003386389, which is the same as multiplying by 295.2998016.
Is the inch of mercury bigger than the megapascal?
No. One inch of mercury is only 0.00338639 of a megapascal, so the megapascal is the larger unit.
Why does my answer differ slightly from other inhg to megapascals converters?
Most differences come from rounding the factor too early. This tool keeps full double precision through the calculation and only rounds at the final display step, and it also shows the unrounded value so you can see exactly where any difference appears.
What is a inch of mercury?
US aviation and weather altimeter setting unit.
What is a megapascal?
Used for material strength and hydraulic systems.
Inches Of Mercury to megapascals reference table
| Inches Of Mercury | Megapascals |
|---|---|
| 0.5 inHg | 0.001693 MPa |
| 1 inHg | 0.003386 MPa |
| 2 inHg | 0.006773 MPa |
| 3 inHg | 0.010159 MPa |
| 5 inHg | 0.016932 MPa |
| 10 inHg | 0.033864 MPa |
| 15 inHg | 0.050796 MPa |
| 20 inHg | 0.067728 MPa |
| 25 inHg | 0.08466 MPa |
| 50 inHg | 0.169319 MPa |
| 75 inHg | 0.253979 MPa |
| 100 inHg | 0.338639 MPa |
| 250 inHg | 0.846597 MPa |
| 500 inHg | 1.6932 MPa |
| 1000 inHg | 3.3864 MPa |
Exact factor: 1 inch of mercury = 0.003386389 megapascals. Values rounded for display.