Convert pressure units — pascal, PSI, bar, atmosphere, torr, mmHg and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 atm | 1.01325 mbar | |
| 0.01 atm | 10.1325 mbar | |
| 0.1 atm | 101.325 mbar | |
| 1 atm | 1013.25 mbar | |
| 5 atm | 5066.25 mbar | |
| 10 atm | 10132.5 mbar | |
| 50 atm | 50662.5 mbar | |
| 100 atm | 101325 mbar | |
| 1000 atm | 1.01325e+06 mbar |
Formula: Millibar = Atmosphere × 1013
Multiply any atmosphere value by 1013 to get millibar.
Reverse: Atmosphere = Millibar × 0.0009869
Common atmosphere values — factor: 1 atm = 1013 mbar
| Atmosphere (atm) | Millibar (mbar) | Context |
|---|---|---|
| 0.001 atm | 1.013 mbar | Vacuum |
| 0.01 atm | 10.13 mbar | High vacuum |
| 0.1 atm | 101.3 mbar | Mountain top |
| 0.5 atm | 506.6 mbar | Half atmosphere |
| 1 atm | 1,013 mbar | Sea level |
| 2 atm | 2,026 mbar | 10 m water depth |
| 5 atm | 5,066 mbar | 40 m depth |
| 10 atm | 1.013e+04 mbar | 90 m depth |
| 50 atm | 5.066e+04 mbar | 500 m depth |
| 100 atm | 101,300 mbar | 1 km depth |
| 500 atm | 506,600 mbar | 5 km depth |
| 1,000 atm | 1,013,000 mbar | 10 km depth |
| 5,000 atm | 5,066,000 mbar | Deep mantle |
| 1e+04 atm | 10,130,000 mbar | Very deep mantle |
| 5e+04 atm | 50,660,000 mbar | Diamond formation |
1 atm = 1013 mbar. Memorize for instant estimates.
Use 1013 as a quick mental multiplier.
Multiply result by 0.0009869 to recover the original atm value.
Uses atmospheres in gas law calculations (PV = nRT) and solubility studies.
Calculates dive depth pressure (every 10 m adds ~1 atm) for dive tables.
Designs diamond anvil cell experiments measuring pressure in thousands of atm.
Specifies autoclave and reactor operating pressures relative to atm.
Estimates metamorphic rock formation pressures in kbar (thousands of atm).
Plans saturation diving operations using atm for depth-pressure calculations.
The atmosphere (atm) is defined as exactly 101,325 pascals — the approximate air pressure at sea level. It was originally defined as the average atmospheric pressure at sea level at 45° latitude, and has been a standard reference since the 17th century.
Atmospheres are used in chemistry (gas laws), scuba diving depth calculations (every 10 m of water ≈ 1 additional atm), and as a convenient reference for extreme pressure comparisons.
Interesting fact: Jupiter's atmosphere has pressures exceeding 1,000 atm at depth. Diamond formation in Earth's mantle requires pressures of 45,000–60,000 atm at depths of 150–200 km.
The millibar (mbar) equals 0.001 bar or 100 pascals, and is numerically identical to the hectopascal (hPa). It became the standard unit for surface pressure in international meteorology in the 20th century.
Weather maps and forecasts worldwide use millibars or hectopascals for surface pressure. Standard sea-level pressure is 1013.25 mbar. Hurricanes and typhoons are characterized by very low central pressures — Hurricane Patricia (2015) reached 872 mbar.
Interesting fact: A 1 mbar pressure difference over 111 km (1° latitude) drives a wind of approximately 1 m/s in mid-latitudes, which is why steep pressure gradients produce strong winds.
Converting atmosphere to millibar is a common task in engineering, medicine, meteorology, and science. Different industries and countries use different pressure units — PSI in the US, bar in Europe, mmHg in medicine, and pascals in physics — making accurate conversion essential for cross-disciplinary work.
Quick reference: 5 atm = 5066 mbar and 10 atm = 1.013e+04 mbar. For the reverse: 1 mbar = 0.0009869 atm. The exact factor is 1 atm = 1013 mbar.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.