Pressure

mmHg to Inches of Mercury

Convert mmhg to inches of mercury instantly. 1 mmHg = 0.0393700746 inHg. Includes the exact factor, a conversion table of common values and the definition of both units.

mmHg
Inches of Mercury
One step, one exact factormmHgwhat you have× 0.0393700746Inches of Mercurywhat you getBoth units are defined against the same base unit, so the factor is exact — never an approximation.

How to convert mmhg to inches of mercury

To convert mmhg to inches of mercury, divide by 25.4000026977 (multiply by 0.0393700746). The relationship is fixed, so the same factor works for any quantity — there is nothing to look up and nothing that changes with temperature, location or context.

inHg = mmHg × 0.0393700746

mmHg to Inches of Mercury conversion table

The values people look up most often, rounded for reading. Use the calculator above for anything in between.

mmHgInches of Mercury
1 mmHg0.03937 inHg
2 mmHg0.07874 inHg
3 mmHg0.11811 inHg
5 mmHg0.19685 inHg
10 mmHg0.393701 inHg
20 mmHg0.787401 inHg
25 mmHg0.984252 inHg
50 mmHg1.968504 inHg
100 mmHg3.937007 inHg
500 mmHg19.685037 inHg
1,000 mmHg39.370075 inHg

What is a mmhg?

Millimetres of mercury, still the clinical unit for blood pressure.

What is a inches of mercury?

The aviation altimeter unit: 29.92 inHg is standard sea-level pressure.

The formula

inHg = mmHg × 0.0393700746

Every result on this page comes from this formula. Nothing is rounded until the final display, so figures match a spreadsheet to the cent.

How to use the mmHg to Inches of Mercury

  1. Type the number of mmhg you want to convert.
  2. Read the result in inches of mercury straight away — there is no button to press.
  3. Check the table below for the values that come up most often, or reverse the conversion with the linked inches of mercury to mmhg page.

mmHg to Inches of Mercury — frequently asked questions

How many inches of mercury are in a mmhg?

One mmhg equals 0.0393700746 inHg. inHg = mmHg × 0.0393700746

What is the formula to convert mmhg to inches of mercury?

The formula is inHg = mmHg × 0.0393700746. It is an exact definition rather than an approximation, so the conversion never drifts no matter how large the number.

How do I convert inches of mercury back to mmhg?

Divide instead of multiplying: one inches of mercury is 25.4000026977 mmHg. The reverse converter is linked in the related tools list.

Is this conversion exact?

Yes. Both units are defined against the same base unit by international agreement, so the factor is exact — any rounding you see is only in the display, which you can widen by entering more decimal places.

Is this mmhg to inches of mercury free to use?

Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.

What people search for

This page answers each of these searches. They are the exact phrases visitors use to find the mmhg to inches of mercury.

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About this calculator

Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.

Last reviewed August 19, 2026 · Calculation runs client-side · No data collected · Report an error