Convert Pa to bar pascals ↔ bars Free Online Secure
Type a value in pascals and read it in bars at once. The factor is exact by definition, the arithmetic happens in your browser, and nothing is sent anywhere.
Nothing uploaded
Common values — Convert Pa to bar (pascals ↔ bars)
| Pa | bar |
|---|---|
| 1 | 0.00001 |
| 2 | 0.00002 |
| 3 | 0.00003 |
| 5 | 0.00005 |
| 10 | 0.0001 |
| 20 | 0.0002 |
| 50 | 0.0005 |
| 100 | 0.001 |
Where these units come from
Pressure is force spread over an area, and the SI unit says so plainly: a pascal is one newton on one square metre. It is a very small amount — ordinary air presses on us with about 101,325 of them — so practical work uses multiples. The bar was invented in the 1900s by the meteorologist Vilhelm Bjerknes as a round 100,000 pascals, close enough to sea-level air pressure to be a convenient yardstick, and it stuck in weather, in diving and in tyre gauges across Europe. The pound per square inch came the other way, straight from the pound and the inch, and it still rules American industry and the garage forecourt.
Where you meet them
Tyres are the place most people meet pressure, quoted in bar in Europe and in psi in the United States and Britain. Beyond that: weather maps in hectopascals, which are the same number as millibars; boilers, hydraulics and compressed air in bar; gas cylinders, hoses and engine testing in psi; and vacuum work in pascals, where the small unit is finally the right size.
Questions people ask
Is a hectopascal the same as a millibar?
Exactly the same, which is why weather forecasts switched between them without anyone noticing. A bar is 100,000 pascals, so a millibar is 100 pascals, and a hectopascal is also 100 pascals. Standard sea-level pressure is 1013.25 of either. Meteorology moved to hectopascals to stay inside the SI, keeping the familiar numbers unchanged.
How is a bar related to atmospheric pressure?
A bar is exactly 100,000 pascals, which is close to the atmosphere but not equal to it: standard atmospheric pressure is 1.01325 bar. Under water the pressure rises by roughly one bar for every ten metres of depth, so a diver at 30 metres feels about four bar in total, counting the air above.
Is the answer exact?
Where both units are defined in terms of one another by whole numbers, yes — the page says so above the figure, and the only rounding is in how many digits are shown. Where the ratio has no finite decimal, the page shows twelve significant digits and says the relation is approximate rather than pretending otherwise.
Does anything I type leave my device?
No. The arithmetic runs in your browser; nothing is uploaded and there is no server to upload it to. Load the page once and it keeps working with the network switched off.
Pascals to bar: from the faintest sound to the bottom of the ocean
The pascal is the SI unit of pressure, and it is tiny. A sheet of paper on a table presses on it with less than one pascal, a whisper with a few hundred-thousandths of one. Physicists, acousticians and vacuum engineers therefore work with pascals and their prefixes, but pumps, tyres and boilers are labelled in bar, a unit 100,000 times larger. To convert Pa to bar, divide by 100,000: 101,325 Pa is 1.01325 bar, 250,000 Pa is 2.5 bar and 1,000,000 Pa is 10 bar. The calculator above divides as you type, and the sections below put the numbers in the settings where they turn up.
The page gives the rule with worked examples, a profile of each unit, a comparison and a long series of examples at very small and very large pressures, followed by the common slips. The calculation runs in your browser and nothing you type is sent anywhere. For design work, follow the relevant standard.
How to convert Pa to bar: divide by 100,000
The rule
A bar is defined as exactly 100,000 pascals, so the conversion is just a shift of the decimal point by five places. To convert Pa to bar, 500 Pa gives 0.005 bar, 9,810 Pa gives 0.0981 bar, 220,000 Pa gives 2.2 bar and 25,000,000 Pa gives 250 bar. To go the other way, multiply bar by 100,000.
Worked examples
Standard atmospheric pressure is 101,325 Pa, or 1.01325 bar. A chimney draught of 15 Pa is 0.00015 bar. A water main at 400,000 Pa is at 4 bar, and a diving cylinder at 20,000,000 Pa holds 200 bar.
No rounding anywhere
The bar is defined as 100,000 Pa, so the factor is exact. The only difficulty is the number of zeros, which is why prefixes are used: 1 hPa is 100 Pa, 1 kPa is 1,000 Pa and 1 MPa is 10 bar.
A quick sanity test
The answer in bar is a hundred thousand times smaller than the number of pascals. If a “convert Pa to bar” calculation gave a bigger number than you started with, you multiplied by mistake.
The pascal
The SI unit of pressure
The pascal is the pressure produced by a force of one newton on an area of one square metre. It is named after Blaise Pascal. Physics books, ventilation standards, acoustics and materials science use it.
Where it appears
Physics, meteorology in hectopascals, ventilation, acoustics and strength of materials.
The bar
The practical unit
The bar equals 100,000 pascals and is close to the pressure of the atmosphere at sea level. It is the unit on tyre gauges, compressors and industrial installations in most countries.
Where it appears
Installations, tyres, compressors, boilers and industrial equipment.
Pascal against bar
One pascal is 0.00001 bar. A pressure of 100,000 Pa is 1 bar and one of 10 million Pa is 100 bar. The numbers in pascals are large for everyday pressures, and the numbers in bar are small for laboratory ones.
The choice of unit therefore depends on the field. The main trap is the count of zeros: one place out changes the result tenfold.
Where the conversion shows up
Sound pressure
The quietest sound a young ear can detect is 20 micropascals, 2 × 10⁻¹⁰ bar. One pascal corresponds to 94 dB, 20 Pa to 120 dB and 63 Pa to about 130 dB, the threshold of pain. A normal conversation has a sound pressure near 0.02 Pa, 2 × 10⁻⁷ bar. A “convert Pa to bar” calculation shows how faint such pressure variations are against a background of one bar.
Vacuum technology
A rough pump reaches 1 Pa, 10⁻⁵ bar. A coating chamber works at 10⁻³ Pa and a space simulation chamber at 10⁻⁷ Pa or less. In pascals the numbers are manageable; in bar they would have a dozen zeros.
Planetary atmospheres
The surface of Mars has about 600 Pa, 0.006 bar, under 1 per cent of Earth's. Venus has 9.2 MPa, 92 bar, equal to the pressure in the ocean at 900 metres. Landers are designed for such values.
What one pascal feels like
A layer of water 0.1 mm deep exerts about one pascal. A column of water 10 metres tall adds 98,100 Pa, 0.981 bar. An ordinary sheet of 80 g/m² paper presses on a table with about 0.8 Pa. These figures show how small the pascal is compared with practical needs.
Strength of materials
Stresses in steel are given in megapascals. Structural steel yields at 235 MPa, 2,350 bar, and ordinary concrete crushes at about 25 MPa, 250 bar. For structural engineers 1 MPa is exactly 10 bar.
Blood pressure
Doctors quote blood pressure in millimetres of mercury. A reading of 120 mmHg is 16,000 Pa, 0.16 bar, and 80 mmHg is 10,700 Pa, 0.107 bar. One millimetre of mercury is 133.3 Pa.
Tyres in kilopascals
Many manufacturers give tyre pressures in kPa: 220 kPa is 220,000 Pa, 2.2 bar. The step from kPa to bar divides by 100, and from Pa to bar by 100,000. A “convert Pa to bar” calculation done with 1,000 instead of 100,000 produces absurd results.
Wing loading
The lift on a wing comes from a pressure difference between its surfaces. On a light aircraft the average difference is 600 to 1,000 Pa, 0.006 to 0.01 bar. Over 16 square metres of wing that supports 1,000 to 1,600 kilograms. Pascals are the natural unit for such calculations.
Filters and pressure drop
A clean air filter in a ventilation system causes a pressure drop of 50 to 100 Pa, and a dirty one 250 to 300 Pa, which is 0.0025 to 0.003 bar. Sensors across the filter read in pascals and trigger a warning when it needs changing.
Hospitals and cleanrooms
An operating theatre is kept at 10 to 25 Pa above the corridor, 0.0001 to 0.00025 bar, so that air flows out and not in. Cleanrooms keep 10 to 15 Pa between classes. The sensors are in pascals; in bar the values would need many decimals.
The mental shortcut
To convert Pa to bar in your head, strike off five zeros. 250,000 Pa becomes 2.5 bar, 80,000 Pa becomes 0.8 bar and 1,500,000 Pa becomes 15 bar. If the number does not have five zeros, move the decimal point five places to the left.
Spreadsheet formulas
To convert Pa to bar in a spreadsheet, put the pressures in pascals in column A and type =A2/100000 in column B. For the reverse, =B2*100000. Format column B in scientific notation if the numbers are very small.
Rounding and precision
Ordinary gauges are accurate to 1 or 2 per cent of the scale. For a 10-bar gauge, one decimal, 2.2 bar, is enough. For very small pressures, such as in ventilation, significant figures matter, not decimal places.
Landmarks to memorise
1 Pa is 0.00001 bar. 100 Pa is 0.001 bar. 1,000 Pa is 0.01 bar. 10,000 Pa is 0.1 bar. 100,000 Pa is 1 bar. 1,000,000 Pa is 10 bar. 10,000,000 Pa is 100 bar. With these you can convert Pa to bar by eye.
The weight of the atmosphere
Standard atmospheric pressure is 101,325 Pa, 1.01325 bar. A column of air above one square metre weighs 101,325 N, about 10.3 tonnes-force. We do not feel it because the pressure inside our bodies balances it.
Reference ladder
500 Pa is 0.005 bar. 5,000 Pa is 0.05 bar. 50,000 Pa is 0.5 bar. 150,000 Pa is 1.5 bar. 300,000 Pa is 3 bar. 800,000 Pa is 8 bar. 2,000,000 Pa is 20 bar. 35,000,000 Pa is 350 bar. A table like this speeds up checks.
Checking by reversing
To check a “convert Pa to bar” calculation result, multiply the answer by 100,000. If 220,000 Pa became 2.2 bar, then 2.2 times 100,000 returns 220,000. A second test is size: the bar figure has five digits fewer.
Link to psi and atmospheres
One bar is 14.5 psi, 0.987 atmospheres and 750 mmHg. A pressure of 220,000 Pa is 2.2 bar, 31.9 psi and 2.17 atmospheres. A pascal is just 0.000145 psi, which is why Americans use psi for ordinary pressures.
A worked example
A heat pump has a high-side pressure of 2,400,000 Pa and a low-side pressure of 600,000 Pa. In bar these are 24 and 6, so the compression ratio is 4. The unit does not matter for the ratio, but the figures in bar are what the technician reads on the gauge.
Gauge and absolute
Gauges usually show pressure relative to the atmosphere. The absolute value is greater by 101,325 Pa, 1.01325 bar. A gauge reading of 2.2 bar means an absolute pressure of 3.21 bar, which is 321,325 Pa.
Aircraft cabins
The pressure in an airliner cabin is around 75,000 to 80,000 Pa, 0.75 to 0.80 bar, equal to the pressure at 2,000 to 2,500 metres. Ground pressure is 101,325 Pa, so the cabin at cruise holds a quarter less.
Hydrostatic pressure
Pressure at depth h is ρ × g × h; for water, 9,810 Pa per metre. At 5 metres the gauge pressure is 49,050 Pa, 0.49 bar, and the absolute pressure 150,375 Pa, 1.50 bar. Pools and tanks are designed from these values.
Water towers
A water tower 40 metres high gives 392,400 Pa, 3.92 bar, at its base. That is why town water systems have reservoirs on hills. The pressure depends only on the height, not on the shape of the tank.
From pressure to force
Force equals pressure times area. A pressure of 2.2 bar, 220,000 Pa, on 1 cm², 0.0001 m², gives 22 N. On a piston of 100 cm² it gives 2,200 N. Pascals make the calculation direct because newtons and square metres fit together.
Useful prefixes
1 hPa is 100 Pa, 0.001 bar. 1 kPa is 1,000 Pa, 0.01 bar. 1 MPa is 1,000,000 Pa, 10 bar. 1 GPa is a billion pascals, 10,000 bar. The core of the Earth exceeds 300 GPa. Prefixes avoid long strings of zeros.
Altitude
Near the ground pressure falls by about 12 Pa per metre of climb, 0.00012 bar. At 1,000 metres it is 89,900 Pa, 0.899 bar, at 3,000 metres 70,100 Pa, 0.701 bar, and on Everest 33,700 Pa, 0.337 bar. Altimeters work on this relation.
Two routes to one answer
You can go from pascals to bar directly, dividing by 100,000, or via kPa: divide by 1,000 and then by 100. If they disagree, a digit was copied wrongly.
Gas in the home
Natural gas reaches a household burner at about 2,000 Pa, which is 20 millibar or 0.02 bar. A mains regulator brings it down from several bar in the street. Installers measure the small pressures with a U-tube or a digital manometer reading in pascals, and a “convert Pa to bar” calculation puts their findings on the same scale as the street supply.
The deepest ocean
At the bottom of the Challenger Deep, about 10,900 metres down, the pressure is around 110 MPa, 1,100 bar. That is 110,000,000 Pa, more than a thousand times atmospheric. Submersibles are built with thick spheres of titanium or glass so that the hull is compressed evenly, not crushed.
Barometer and storms
A fall of 300 Pa, 0.003 bar, in three hours warns of an approaching storm, while a rise of the same size promises fair weather. Sailors and hikers follow the trend rather than the absolute value. A “convert Pa to bar” calculation puts figures from different sources on one scale.
Weather records
The highest sea-level pressure ever measured, 108,380 Pa, 1.0838 bar, was recorded in Mongolia in a bitter winter. The lowest, about 87,000 Pa, 0.87 bar, was in the eye of a typhoon. The whole range of 21,380 Pa is 0.2138 bar.
Wind pressure
The dynamic pressure of the wind is roughly 0.6125 × v² pascals with v in m/s. At 20 m/s that gives 245 Pa, 0.00245 bar, and at 40 m/s 980 Pa. A roof copes with ordinary wind easily but not with the gusts of a hurricane.
Chimney draught
A 10-metre chimney with flue gases at 200 °C produces a draught of about 40 Pa. Regulations ask for 10 to 25 Pa at the flue entry. Values of 0.0001 to 0.0004 bar cannot be read on ordinary gauges, so special manometers are used.
Vacuum cleaners
A household vacuum cleaner develops a suction of 15,000 to 25,000 Pa, 0.15 to 0.25 bar, below atmospheric pressure. Industrial models reach 20,000 to 30,000 Pa. The data sheets often give kPa or mbar, and a “convert Pa to bar” calculation brings them to a common scale.
Ultra-high vacuum
Ultra-high vacuum starts at 10⁻⁷ Pa, 10⁻¹² bar, and is used in surface science and in particle accelerators. Deep space has about 10⁻¹² Pa. In such regimes the pascal is the only practical unit, because the bar would require twelve zeros after the decimal point.
High pressure in megapascals
A diving cylinder holds air at 20 MPa, 200 bar. An industrial washer works at 20 to 50 MPa, 200 to 500 bar. The bed of the deepest ocean trench carries 110 MPa, 1,100 bar. The megapascal is the natural prefix for these pressures, with 1 MPa equal to 10 bar.
More values for convert Pa to bar
A longer list of conversions
If the value you need is not in the first list, these further conversions may be close enough to read off directly:
- 0.1 Pa = 0.000001 bar
- 0.5 Pa = 0.000005 bar
- 3 Pa = 0.00003 bar
- 4 Pa = 0.00004 bar
- 7 Pa = 0.00007 bar
- 15 Pa = 0.00015 bar
- 20 Pa = 0.0002 bar
- 75 Pa = 0.00075 bar
- 200 Pa = 0.002 bar
- 500 Pa = 0.005 bar
- 2,000 Pa = 0.02 bar
- 10,000 Pa = 0.1 bar
Common slips with a “convert Pa to bar” calculation
Multiplying instead of dividing
From pascals to bar the number shrinks. If 220,000 Pa became 22,000,000,000, you multiplied by mistake.
The decimal point
Dividing by 100,000 shifts the point five places. One place out makes the result ten times too large or too small.
Mixing hPa and Pa
One hectopascal is 100 Pa, not 1 Pa. A reading of 1,013 hPa is 101,300 Pa, 1.013 bar.
Short answers
How do I convert Pa to bar?
Divide the pascals by 100,000.
How many bar is 101,325 Pa?
1.01325 bar.
How many bar is 220,000 Pa?
2.2 bar.
How many pascals in 1 bar?
Exactly 100,000 Pa.
Does my number leave my device?
No, the calculation runs in your browser.
More pages and a wrap-up
For other pressure conversions see Convert psi to bar, Convert bar to psi, Convert km to mi, Convert mi to km, Convert °C to °F, Convert °F to °C, Convert km/L to MPG (US), Convert W to hp, Convert µm to mm. The reverse direction is Convert bar to Pa.
In short, a “convert Pa to bar” calculation comes down to dividing by 100,000 and writing the unit beside the answer. Your number is computed locally, with no account and no upload.