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Atm to mmHg converter, atmospheres into millimetres of mercury.
Type atmospheres and read mmHg. One standard atmosphere is 760 mmHg, the same as 760 Torr. Cards give kPa, psi and bar.
1 atm equals
760 mmHg
1 standard atmosphere = 760 mmHg exactly1 millimeter of mercury = 0.001315789474 atm (rounded)
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Gauge or absolute?
Common values, click one to use it
| Standard atmospheres | Millimeters of mercury |
|---|---|
| 7.6 mmHg | |
| 38 mmHg | |
| 76 mmHg | |
| 190 mmHg | |
| 380 mmHg | |
| 570 mmHg | |
| 684 mmHg | |
| 760 mmHg | |
| 836 mmHg | |
| 950 mmHg | |
| 1,140 mmHg | |
| 1,520 mmHg | |
| 2,280 mmHg | |
| 3,040 mmHg | |
| 3,800 mmHg | |
| 4,560 mmHg | |
| 6,080 mmHg | |
| 7,600 mmHg | |
| 15,200 mmHg | |
| 38,000 mmHg |
Standard atmospheres to millimeters of mercury chart
- 0.01 atm7.6 mmHg
- 0.05 atm38 mmHg
- 0.1 atm76 mmHg
- 0.2 atm152 mmHg
- 0.25 atm190 mmHg
- 0.3 atm228 mmHg
- 0.4 atm304 mmHg
- 0.5 atm380 mmHg
- 0.6 atm456 mmHg
- 0.7 atm532 mmHg
- 0.75 atm570 mmHg
- 0.8 atm608 mmHg
- 0.9 atm684 mmHg
- 0.95 atm722 mmHg
- 1 atm760 mmHg
- 1.05 atm798 mmHg
- 1.1 atm836 mmHg
- 1.25 atm950 mmHg
- 1.5 atm1,140 mmHg
- 2 atm1,520 mmHg
- 2.5 atm1,900 mmHg
- 3 atm2,280 mmHg
- 4 atm3,040 mmHg
- 5 atm3,800 mmHg
- 6 atm4,560 mmHg
- 8 atm6,080 mmHg
- 10 atm7,600 mmHg
- 20 atm15,200 mmHg
- 50 atm38,000 mmHg
- 100 atm76,000 mmHg
Worked out in your browser. Nothing is sent anywhere.
Guide
How to convert atm to mmHg, 760 and the tiny difference.
To convert atm to mmHg, multiply by 760. So 1 atm is 760 mmHg, which is the same as 760 Torr. 0.5 atm is 380 mmHg and 2 atm is 1,520 mmHg. For blood pressure, weather and lab work, 760 is the number to use.
How to use the converter
- Type the amount in the Standard atmospheres (atm) box. A decimal such as 2.5 or a fraction such as 3/4 works.
- The big result shows Millimeters of mercury (mmHg). Use Decimals in the side column to fix the number of places.
- The first card gives Torr, the unit defined as exactly 1/760 of an atmosphere. Others give kPa, psi and bar.
- Type in the second box, or press the swap button, to convert millimeters of mercury to standard atmospheres instead.
- Click a row in Common values to load it. Copy result, Copy link, Copy table and Print chart keep the answer. Start again resets the box.
Why mmHg and Torr are the same here
The torr is defined as exactly 1/760 of a standard atmosphere, which is 101,325 ÷ 760 = 133.322368 Pa. NIST SP 811 lists the conventional millimetre of mercury as 1.333 224 E+02 Pa, the same figure it prints for the torr, and its footnote says extra digits are not justified for mercury units. So this converter takes 1 mmHg as equal to 1 Torr, and 1 atm is 760 mmHg.
Atm to mmHg, a table
| atm | mmHg (Torr) | kPa |
|---|---|---|
| 0.1 | 76 | 10.133 |
| 0.25 | 190 | 25.331 |
| 0.5 | 380 | 50.663 |
| 0.75 | 570 | 75.994 |
| 0.9 | 684 | 91.193 |
| 1 | 760 | 101.325 |
| 1.1 | 836 | 111.458 |
| 1.5 | 1,140 | 151.988 |
| 2 | 1,520 | 202.65 |
| 3 | 2,280 | 303.975 |
| 5 | 3,800 | 506.625 |
| 10 | 7,600 | 1,013.25 |
Worked examples
- A weather report of 0.98 atm. 0.98 × 760 = 744.8 mmHg.
- A vacuum chamber at 0.01 atm. 7.6 mmHg.
- 3 atm in kPa. 303.98 kPa.
- Back the other way. 600 mmHg = 0.7895 atm. Press the swap button and type 600.
Gauge or absolute pressure
A tyre gauge, a pressure washer dial and most boiler gauges show gauge pressure, which is the pressure above the air around them. Absolute pressure counts from a perfect vacuum, so it is the gauge reading plus the air pressure. At one standard atmosphere, 101.325 kPa, 1 atm gauge is 2 atm absolute. The Gauge or absolute box above the tables does the sum in either direction. Air pressure changes with weather and height, so one standard atmosphere is only an average. The standard atmosphere is from NIST SP 811 Appendix B.8, checked 24 Oct 2026.
Where the numbers come from
NIST SP 811, Appendix B.8 lists the standard atmosphere as 1.013 25 E+05 Pa (exact), the conventional millimetre of mercury as 1.333 224 E+02 Pa, and the torr as 1.333 224 E+02 Pa. The NIST footnotes say that mercury unit factors use standard gravity and that more digits are not justified. Checked 24 Oct 2026. The converter keeps the factors as exact fractions and rounds only the last digit shown. It is a unit converter, not a safety tool: for a tyre, boiler or tank, use the value printed on the equipment or in its manual.
Mistakes to avoid
Do not use inches of mercury (inHg) with this factor: 1 atm is about 29.92 inHg, not 760. And mmHg for blood pressure is a reading above the surrounding air, which is a gauge reading.
Related pages: Bar to atm, Bar to psi, Psi to kPa and Unit converter.
Questions
Good to know.
How many mmHg is 1 atm?
760 mmHg, the same as 760 Torr.
Is mmHg the same as Torr?
For this converter, yes. NIST prints the same figure, 133.3224 Pa, for both, and says more digits are not justified.
How many mmHg is 2 atm?
1,520 mmHg.
How many atm is 380 mmHg?
Half an atmosphere, 0.5 atm.
How many kPa is 760 mmHg?
About 101.325 kPa.
What does "standard atmosphere" mean?
A fixed pressure of 101,325 pascals.
What is the difference between gauge and absolute pressure?
Gauge pressure is measured above the surrounding air. Absolute pressure is measured from a vacuum. Absolute is the gauge reading plus about 101.325 kPa, one standard atmosphere.