kPa to Bar Converter
1 bar = 100 kPa exactly. Type in either box.
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The easiest pressure conversion there is
A bar is defined as exactly 100,000 pascals, and a kilopascal is exactly 1,000 pascals. So one bar is exactly one hundred kilopascals, and the conversion is nothing more than moving a decimal point two places.
1 bar = 100 kPa exactly
220 kPa is 2.2 bar. 101.325 kPa is 1.01325 bar. There is no rounding error anywhere in this conversion, because both units are defined against the pascal with exact powers of ten.
This is also why weather forecasts can quote hectopascals and millibars interchangeably: a hectopascal is a hundred pascals, a millibar is a thousandth of a bar, and both work out at exactly the same size.
The kilopascal
A thousand pascals, and the size that suits everyday pressures. Car tyres run at roughly 200–250 kPa, the atmosphere sits at about 101 kPa, and a domestic water supply is usually somewhere between 200 and 500 kPa.
It is the working unit for pressure through most of the metric world, which is why tyre placards in Europe, Australia and Asia are marked in kPa alongside the bar figure.
The bar
The bar was defined to be close to atmospheric pressure at sea level, and it very nearly is — one bar is 0.987 atmospheres. It is not an SI unit, but it survives because the number is convenient and because so much European equipment is calibrated in it.
You will find it on espresso machines (9 bar at the group head), diving equipment (200 bar in a full cylinder) and industrial gauges across Europe.
The working, step by step
Every line updates with whatever you type above. The point is the method, which is the same for any pair of units in this family.
The same quantity, two different numbers
One physical amount, read off two scales. The tick marks do not line up, and the gap between them is the conversion factor made visible.
How much is that?
A number is easier to judge next to something familiar.
Your turn
Reading a method and being able to use it are different things. Answer within half a per cent and it counts as correct.
Score: 0 of 0
How to use this converter
- Type into either box. The other side updates as you go; there is no button to press.
- Swap the direction with the button between the boxes, carrying your value across.
- Set the decimals if the default is more or less precision than you need.
- Copy the answer with its unit, ready to paste.
- Use the shortcut buttons for the values that come up most often.
- Share the result. The address bar tracks what you type, so the link you copy opens on the same number.
Common uses and tips
Where pressure conversions come up
- Tyres. The single most common reason anyone converts pressure. American placards are in psi, European and Asian ones in bar or kPa, and the three appear side by side on the same door sticker.
- Weather. Forecasts use hectopascals or millibars, which are the same size — 1 hPa is 1 mbar. A typical high-pressure system reads about 1020 of either.
- Diving. Cylinder pressures are in bar almost everywhere and psi in the United States. A full 200 bar cylinder is about 2,900 psi.
- Coffee. Espresso machines are specified in bar; nine bar at the group head is the usual target, which is about 130 psi.
- Materials and hydraulics. Tensile strength and hydraulic ratings come in MPa or psi, and the two communities rarely use the same one.
The trap: gauge pressure and absolute pressure
Almost every pressure you read off a dial in daily life is gauge pressure — how much higher than the surrounding air it is. A tyre at 32 psi contains 32 psi more than the atmosphere, so its absolute pressure is about 46.7 psi.
Conversion between units never changes which of the two you have. If you start with a gauge reading you end with a gauge reading. Where it goes wrong is in physics and chemistry, where the gas laws need absolute pressure: add one atmosphere to a gauge figure before it goes into a calculation. The units psig and psia exist precisely to keep the two apart.
Tips worth knowing
- One bar is not one atmosphere. It is 0.9869 of one. The difference is small enough to ignore for a tyre and large enough to matter in a laboratory.
- Millibars and hectopascals are identical. Weather maps use whichever the local service prefers; the number is the same.
- One MPa is about ten atmospheres, which makes megapascals easy to sanity-check against everyday pressures.
- Torr and mmHg are interchangeable in practice, differing by about one part in seven million.
Values people look up most
Each one opens the converter with the number already in it.
- 1 kPa to bar
- 10 kPa to bar
- 50 kPa to bar
- 100 kPa to bar
- 101.325 kPa to bar
- 150 kPa to bar
- 200 kPa to bar
- 220 kPa to bar
- 250 kPa to bar
- 300 kPa to bar
- 400 kPa to bar
- 500 kPa to bar
- 600 kPa to bar
- 800 kPa to bar
- 1,000 kPa to bar
- 2,000 kPa to bar
Quick reference
| Kilopascals | Bar |
|---|---|
| 1 kPa | 0.01 bar |
| 10 kPa | 0.1 bar |
| 50 kPa | 0.5 bar |
| 100 kPa | 1 bar |
| 101.325 kPa | 1.01325 bar |
| 200 kPa | 2 bar |
| 220 kPa | 2.2 bar |
| 300 kPa | 3 bar |
| 500 kPa | 5 bar |
| 1,000 kPa | 10 bar |
| 2,000 kPa | 20 bar |
| 20,000 kPa | 200 bar |
Questions people ask
How many kPa in a bar?
Exactly 100. Both units are defined against the pascal, so there is no approximation involved.
Is a millibar the same as a hectopascal?
Yes, exactly. Both equal 100 pascals, which is why weather services use them interchangeably.
What is 220 kPa in bar?
2.2 bar — a normal car tyre pressure.
Does this convert gauge or absolute pressure?
Whichever you put in. Converting units does not change which kind of pressure you have — a gauge reading converts to a gauge reading. If a calculation needs absolute pressure, add one atmosphere first.