Millimeters of Mercury to Atmospheres (mmHg → atm) — Free Online Converter

mmHg → atm Reference Table

mmHg	atm
0.001 mmHg	0.000001315789661 atm
0.002 mmHg	0.000002631579322 atm
0.003 mmHg	0.000003947368983 atm
0.004 mmHg	0.000005263158645 atm
0.005 mmHg	0.000006578948306 atm
0.006 mmHg	0.000007894737967 atm
0.007 mmHg	0.000009210527628 atm
0.008 mmHg	0.00001052631729 atm
0.009 mmHg	0.00001184210695 atm
0.01 mmHg	0.00001315789661 atm
0.02 mmHg	0.00002631579322 atm
0.03 mmHg	0.00003947368983 atm
0.04 mmHg	0.00005263158645 atm
0.05 mmHg	0.00006578948306 atm
0.06 mmHg	0.00007894737967 atm
0.07 mmHg	0.00009210527628 atm
0.08 mmHg	0.0001052631729 atm
0.09 mmHg	0.0001184210695 atm
0.1 mmHg	0.0001315789661 atm
0.2 mmHg	0.0002631579322 atm
0.3 mmHg	0.0003947368983 atm
0.4 mmHg	0.0005263158645 atm
0.5 mmHg	0.0006578948306 atm
0.6 mmHg	0.0007894737967 atm
0.7 mmHg	0.0009210527628 atm
0.8 mmHg	0.001052631729 atm
0.9 mmHg	0.001184210695 atm
1 mmHg	0.001315789661 atm
1.5 mmHg	0.001973684492 atm
2 mmHg	0.002631579322 atm
2.5 mmHg	0.003289474153 atm
3 mmHg	0.003947368983 atm
3.5 mmHg	0.004605263814 atm
4 mmHg	0.005263158645 atm
4.5 mmHg	0.005921053475 atm
5 mmHg	0.006578948306 atm
5.5 mmHg	0.007236843136 atm
6 mmHg	0.007894737967 atm
6.5 mmHg	0.008552632797 atm
7 mmHg	0.009210527628 atm
7.5 mmHg	0.009868422459 atm
8 mmHg	0.01052631729 atm
8.5 mmHg	0.01118421212 atm
9 mmHg	0.01184210695 atm
9.5 mmHg	0.01250000178 atm
10 mmHg	0.01315789661 atm
11 mmHg	0.01447368627 atm
12 mmHg	0.01578947593 atm
13 mmHg	0.01710526559 atm
14 mmHg	0.01842105526 atm
15 mmHg	0.01973684492 atm
16 mmHg	0.02105263458 atm
17 mmHg	0.02236842424 atm
18 mmHg	0.0236842139 atm
19 mmHg	0.02500000356 atm
20 mmHg	0.02631579322 atm
25 mmHg	0.03289474153 atm
30 mmHg	0.03947368983 atm
35 mmHg	0.04605263814 atm
40 mmHg	0.05263158645 atm
45 mmHg	0.05921053475 atm
50 mmHg	0.06578948306 atm
55 mmHg	0.07236843136 atm
60 mmHg	0.07894737967 atm
65 mmHg	0.08552632797 atm
70 mmHg	0.09210527628 atm
75 mmHg	0.09868422459 atm
80 mmHg	0.1052631729 atm
85 mmHg	0.1118421212 atm
90 mmHg	0.1184210695 atm
95 mmHg	0.1250000178 atm
100 mmHg	0.1315789661 atm
120 mmHg	0.1578947593 atm
125 mmHg	0.1644737076 atm
130 mmHg	0.1710526559 atm
140 mmHg	0.1842105526 atm
150 mmHg	0.1973684492 atm
160 mmHg	0.2105263458 atm
175 mmHg	0.2302631907 atm
180 mmHg	0.236842139 atm
200 mmHg	0.2631579322 atm
225 mmHg	0.2960526738 atm
250 mmHg	0.3289474153 atm
275 mmHg	0.3618421568 atm
300 mmHg	0.3947368983 atm
350 mmHg	0.4605263814 atm
400 mmHg	0.5263158645 atm
450 mmHg	0.5921053475 atm
500 mmHg	0.6578948306 atm
600 mmHg	0.7894737967 atm
700 mmHg	0.9210527628 atm
750 mmHg	0.9868422459 atm
800 mmHg	1.052631729 atm
900 mmHg	1.184210695 atm
1000 mmHg	1.315789661 atm
1200 mmHg	1.578947593 atm
1250 mmHg	1.644737076 atm
1500 mmHg	1.973684492 atm
1750 mmHg	2.302631907 atm
2000 mmHg	2.631579322 atm
2500 mmHg	3.289474153 atm
3000 mmHg	3.947368983 atm
4000 mmHg	5.263158645 atm
4500 mmHg	5.921053475 atm
5000 mmHg	6.578948306 atm
6000 mmHg	7.894737967 atm
7000 mmHg	9.210527628 atm
7500 mmHg	9.868422459 atm
8000 mmHg	10.52631729 atm
9000 mmHg	11.84210695 atm
10000 mmHg	13.15789661 atm
15000 mmHg	19.73684492 atm
20000 mmHg	26.31579322 atm
25000 mmHg	32.89474153 atm
50000 mmHg	65.78948306 atm
75000 mmHg	98.68422459 atm
100000 mmHg	131.5789661 atm

Why Convert Millimeters of Mercury to Atmospheres?

Converting between millimeters of mercury (mmHg) and atmospheres (atm) is one of the most common pressure conversions. Whether for engineering, cooking, travel, or science, knowing how to quickly convert mmHg to atm saves time and prevents errors.

Pressure conversions between mmHg and atm are vital in automotive maintenance, meteorology, and scuba diving. Tire pressure affects fuel efficiency and safety, requiring drivers to convert between PSI and bar depending on the gauge used. Divers must strictly monitor pressure to avoid decompression sickness, often needing to convert depth and tank pressure readings. In weather forecasting, atmospheric pressure changes indicate approaching storms, with data often shared in different units globally. Failing to convert pressure accurately can lead to equipment failure, tire blowouts, or life-threatening situations underwater.

How to Convert Millimeters of Mercury to Atmospheres

To convert millimeters of mercury to atmospheres, use the following formula:

atm = mmHg × 0.001315789661

Example: 1 mmHg = 0.001315789661 atm

For example, 5 mmHg = 0.006578948306 atm, 10 mmHg = 0.01315789661 atm, and 100 mmHg = 0.1315789661 atm. For larger values, 1000 mmHg = 1.315789661 atm. Conversely, 1 atm = 759.9998917 mmHg. Our calculator above performs this conversion instantly with full precision — no rounding errors.

Common Mistakes to Avoid

Gauge vs Absolute: confusing gauge pressure (psig) with absolute pressure (psia).
Bar vs Pascal: 1 Bar is 100,000 Pascals, not 10 or 100.
Atmosphere variations: confusing standard atm with technical atm.

Pro Tips

Tire checks: Check tire pressure when cold (tires heat up and pressure rises while driving).
PSI rule: Typical car tires are 30-35 PSI.
Altitude effect: Air pressure drops as you go higher (ears popping).

What is a Millimeter of Mercury?

Millimeter of mercury.

Blood pressure and vacuum systems.

What is a Atmosphere?

Standard atmosphere (atm), defined as 101,325 Pascals.

Reference pressure for sea level.

Frequently Asked Questions

How many atmospheres are in 1 millimeter of mercury?

1 mmHg equals 0.001315789661 atm.

How do I convert millimeters of mercury to atmospheres?

Multiply the value in mmHg by the conversion factor. For example, 10 mmHg = 0.01315789661 atm. Use our calculator above for instant results.

Is the millimeters of mercury to atmospheres conversion exact?

This conversion uses NIST SP 811 factors with 10-digit precision, which is more than sufficient for all practical purposes.

Can I convert millimeters of mercury to atmospheres offline?

Yes! OmniConvert runs entirely in your browser — no internet connection needed after the page loads. Your data never leaves your device, ensuring complete privacy.

What is the difference between millimeters of mercury and atmospheres?

Millimeters of Mercury (mmHg) and Atmospheres (atm) are both units of pressure but belong to different measurement systems. 1 mmHg = 0.001315789661 atm. Use the converter above to switch between them instantly.

Millimeters of Mercury → Atmospheres