Pressure

mmHg to Inches of Water

Convert mmhg to inches of water instantly. 1 mmHg = 0.535240179 inH2O. Includes the exact factor, a conversion table of common values and the definition of both units.

mmHg
Inches of Water
One step, one exact factormmHgwhat you have× 0.535240179Inches of Waterwhat 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 water

To convert mmhg to inches of water, divide by 1.8683201286 (multiply by 0.535240179). 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.

inH2O = mmHg × 0.535240179

mmHg to Inches of Water conversion table

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

mmHgInches of Water
1 mmHg0.53524 inH2O
2 mmHg1.07048 inH2O
3 mmHg1.605721 inH2O
5 mmHg2.676201 inH2O
10 mmHg5.352402 inH2O
20 mmHg10.704804 inH2O
25 mmHg13.381004 inH2O
50 mmHg26.762009 inH2O
100 mmHg53.524018 inH2O
500 mmHg267.620089 inH2O
1,000 mmHg535.240179 inH2O

What is a mmhg?

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

What is a inches of water?

A low-pressure unit used for ventilation and gas appliances.

The formula

inH2O = mmHg × 0.535240179

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 Water

  1. Type the number of mmhg you want to convert.
  2. Read the result in inches of water 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 water to mmhg page.

mmHg to Inches of Water — frequently asked questions

How many inches of water are in a mmhg?

One mmhg equals 0.535240179 inH2O. inH2O = mmHg × 0.535240179

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

The formula is inH2O = mmHg × 0.535240179. 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 water back to mmhg?

Divide instead of multiplying: one inches of water is 1.8683201286 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 water 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 water.

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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