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atm to mmHg Converter

1 atm = 760 mmHg (standard atmosphere → millimeter of mercury)

1 atm = 760 mmHg

1 standard atmosphere equals 760 millimeters of mercury. To convert standard atmospheres to millimeters of mercury, multiply the standard atmosphere value by 760. For quick reference: 1 atm = 760 mmHg, 5 atm = 3800 mmHg, 10 atm = 7600 mmHg, 100 atm = 76000 mmHg.

When to use standard atmospheres → millimeters of mercury

Standard atmospheres to millimetres of mercury multiplies by about 760 (101,325 Pa ÷ 133.322387415 Pa per mmHg = 759.9998 mmHg). The near-exact 760 is no accident — the atmosphere was historically defined by a 760 mm mercury column. A 0.5 atm partial pressure is 380.0 mmHg; 2 atm is 1520 mmHg. The subtlety is that the torr is defined as exactly 1/760 atm while the mmHg is defined via mercury density, so the two differ by a few parts in ten million — irrelevant clinically, real in vacuum metrology.

Altitude-physiology researchers studying hypoxia convert barometric pressure from atmospheres into millimetres of mercury because that's the unit blood-gas analysers and pulse-oximetry literature use. Sea level at 1 atm is 760.0 mmHg exactly; the pressure at a high-altitude research station near 0.6 atm is about 456.0 mmHg, enough to noticeably lower blood oxygen saturation. Because 1 atm was originally defined from a 760 mm mercury column, the conversion factor is exact rather than measured — one of the few pressure conversions with zero uncertainty either way.

How to convert standard atmospheres to millimeters of mercury

  1. Take your value

    Start with your value in standard atmospheres.

  2. Multiply by 760

    Multiply the standard atmosphere value by 760. This is the exact conversion factor from standard atmospheres to millimeters of mercury.

  3. Read the result

    The product is your value in millimeters of mercury. For example, 5 atm × 760 = 3800 mmHg.

Conversion formula

The exact factor from standard atmospheres to millimeters of mercury is 760.

Millimeters of mercury = Standard atmospheres × 760

Standard atmospheres to Millimeters of mercury conversion table

Fifty common reference values, hand-picked for skim utility. Use the calculator above for any value not listed.

Conversion table from standard atmospheres to millimeters of mercury
Standard atmospheres (atm)Millimeters of mercury (mmHg)
0.001 atm0.76 mmHg
0.01 atm7.6 mmHg
0.1 atm76 mmHg
0.5 atm380 mmHg
1 atm760 mmHg
1.5 atm1140 mmHg
2 atm1520 mmHg
2.5 atm1900 mmHg
3 atm2280 mmHg
4 atm3040 mmHg
5 atm3800 mmHg
6 atm4560 mmHg
7 atm5320 mmHg
8 atm6080 mmHg
9 atm6840 mmHg
10 atm7600 mmHg
14 atm10640 mmHg
15 atm11400 mmHg
20 atm15200 mmHg
25 atm19000 mmHg
30 atm22800 mmHg
32 atm24320 mmHg
35 atm26600 mmHg
40 atm30400 mmHg
50 atm38000 mmHg
60 atm45600 mmHg
75 atm57000 mmHg
80 atm60800 mmHg
100 atm76000 mmHg
101.325 atm77007 mmHg
150 atm114000 mmHg
200 atm152000 mmHg
250 atm190000 mmHg
300 atm228000 mmHg
400 atm304000 mmHg
500 atm380000 mmHg
760 atm577600 mmHg
1000 atm760000 mmHg
1013.25 atm770070 mmHg
2000 atm1520000 mmHg
5000 atm3799999 mmHg
10000 atm7599999 mmHg
14.7 atm11172 mmHg
50000 atm37999995 mmHg
100000 atm75999989 mmHg
101325 atm77006989 mmHg
200000 atm151999978 mmHg
500000 atm379999946 mmHg
1000000 atm759999892 mmHg
10000000 atm7599998917 mmHg

Real-world reference

Earth's mean sea-level pressure is approximately 1 atm. Pressure doubles roughly every 10 m of seawater. In millimeters of mercury, that gives you: 1 atm = 760 mmHg, 10 atm = 7600 mmHg, 100 atm = 76000 mmHg.

Frequently asked questions

How many millimeters of mercury are in 1 standard atmosphere?
1 standard atmosphere equals 760 millimeters of mercury.
How do I convert standard atmospheres to millimeters of mercury?
Multiply the standard atmosphere value by 760. So x atm × 760 = the equivalent in mmHg.
What is 5 standard atmospheres in millimeters of mercury?
5 standard atmospheres equals 3800 millimeters of mercury.
What is 10 standard atmospheres in millimeters of mercury?
10 standard atmospheres equals 7600 millimeters of mercury.
What is 100 standard atmospheres in millimeters of mercury?
100 standard atmospheres equals 76000 millimeters of mercury.
How do I convert back from millimeters of mercury to standard atmospheres?
Multiply the millimeter of mercury value by 0.00131579. For example, 1 mmHg = 0.00131579 atm.
Is the standard atmosphere bigger than the millimeter of mercury?
Yes. 1 standard atmosphere is larger than 1 millimeter of mercury — specifically 760 times larger.
Are these conversion factors exact?
The factor is derived directly from the SI definitions of standard atmosphere and millimeter of mercury; the displayed value is rounded for readability, and the browser computes using IEEE 754 double-precision arithmetic.

About the standard atmosphere and the millimeter of mercury

The standard atmosphere

The standard atmosphere (atm) is defined as exactly 101,325 Pa. It is the conventional reference for chemistry (gas-law calculations), aviation altimetry, and historic engineering. Despite the name, it is not the actual atmospheric pressure at any single place — that varies daily.

The millimeter of mercury

The millimeter of mercury (mmHg) equals approximately 133.322 Pa — the pressure exerted by a 1 mm column of mercury under standard gravity. It is the conventional unit for blood pressure worldwide, even in countries that have otherwise gone fully metric.

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