mbar to psi Converter
One millibar is 0.0145037738 psi. The arithmetic is easy — what actually trips people up in the vacuum and low-pressure range is whether the mbar figure is absolute and the psi reading is gauge. This tool handles both.
The mbar to psi factor is a definition, not a rounding
One millibar is defined as exactly 100 pascals, and one psi is 6,894.757 pascals. Divide the two and you get 0.0145037738 — the factor this converter uses. Because both units are anchored to the pascal, the conversion is exact at every point on the scale: 250 mbar is 3.626 psi, 500 mbar is 7.252 psi, 1000 mbar is 14.504 psi. Nothing is rounded until you decide how many decimals to keep.
That exactness is worth leaning on. A millibar is a small unit — it takes just under 69 of them to make a single psi — which is exactly why the vacuum and low-pressure world works in mbar: it gives useful resolution where a psi figure would be an awkward string of decimals.
A quick cross-check while you work: 1 psi = 68.947573 mbar, and standard atmosphere is 1013.25 mbar = 14.696 psi absolute.
mbar to psi conversion table
The bar and kPa columns are there as a sanity check — the same pressure written three ways. If a figure in your paperwork disagrees with this table, you are almost certainly comparing gauge against absolute.
| mbar | psi | bar | kPa |
|---|---|---|---|
| 1 | 0.0145 | 0.001 | 0.1 |
| 10 | 0.1450 | 0.01 | 1 |
| 100 | 1.4504 | 0.1 | 10 |
| 250 | 3.6259 | 0.25 | 25 |
| 500 | 7.2519 | 0.5 | 50 |
| 1000 | 14.5038 | 1 | 100 |
| 1013.25 | 14.6959 | 1.01325 | 101.325 |
| 2000 | 29.0076 | 2 | 200 |
Gauge and absolute change the number, not the factor
Multiplying by 0.0145037738 converts the unit. It does not convert the reference. Millibar figures — barometric pressure, vacuum set-points, instrument reference pressures — are almost always absolute, measured from a perfect vacuum. The psi a field gauge shows is almost always gauge, measured from local atmosphere, so it reads zero when the true absolute pressure is one atmosphere.
| mbar a | psi a | psi g (atm 1013.25 mbar) |
|---|---|---|
| 1013.25 | 14.696 | 0.000 |
| 500 | 7.252 | -7.444 |
| 2000 | 29.008 | 14.312 |
Convert 500 mbar absolute to 7.252 psi, compare it to a gauge reading, and you are off by a full atmosphere without either number being wrong — 500 mbar absolute is about -0.5 bar gauge, a partial vacuum. Whenever you cross between mbar and psi down here, settle whether each figure is absolute or gauge first. The absolute, gauge and vacuum converter handles that reference step.
Matching an mbar figure to a real transmitter range
European and vacuum specifications are usually written in mbar or pascals. HMK scales its low-range catalogue in Pa and kPa, so here is the map — the ranges are the actual published ranges of the instruments, not marketing round numbers.
| If your spec says | That is | Instrument to look at |
|---|---|---|
| 0 to 100 mbar | 0 to 10 kPa | HE30 wind & micro-differential, 100 Pa to 100 kPa |
| low DP up to 7 bar | up to 700 kPa | HM30 micro-differential, 500 Pa to 700 kPa |
| vacuum / absolute in mbar | 0.02 Pa to 1 MPa | HM27 vacuum & absolute, ±0.1 % FS |
Related low-pressure tools: the psi to mbar converter runs the same numbers the other way, and the vacuum unit tools cover torr and inches of water.
Frequently Asked Questions
How many psi is 1 mbar?
One millibar is 0.0145037738 psi — about 0.0145 psi.
How do I convert mbar to psi?
Multiply the millibar value by 0.0145037738. The calculator at the top of this page does it instantly and shows bar, kPa and pascals alongside.
Is mbar absolute or gauge pressure?
Millibar figures are usually absolute, referenced to a perfect vacuum. Standard atmosphere is 1013.25 mbar absolute.
What is 1013 mbar in psi?
About 14.69 psi (1013 mbar = 14.692 psi). Standard atmosphere, 1013.25 mbar, is 14.696 psi absolute.
How many mbar are in 1 psi?
One psi is 68.947573 mbar.
Need the transmitter behind the number, not just the conversion?
Tell us the range in mbar, bar or psi — plus the reference and the process medium — and we will match a vacuum, absolute or low-differential transmitter to it.
Transmitters for the mbar and vacuum range
Three HMK instruments that cover the pressures this page converts.
HM270.02 Pa to 1 MPa, vacuum & absoluteVacuum and absolute pressure transmitter, ±0.1 % FS — the reference-matched choice when your mbar figure is absolute.
HE30100 Pa to 100 kPa (wind / micro-DP)Wind and micro-differential sensor for the low-mbar and pascal ranges.
HM30500 Pa to 700 kPa (0.005 to 7 bar)Micro-differential transmitter with response under 2 ms.
Written by Lin Jun · Pressure Instrumentation Engineer, HMK-TECH. Conversion factors follow the SI definitions of the millibar (100 Pa) and the pascal; instrument ranges quoted are the published ranges of the products linked above.