Bar to kPa converter, an exact factor of one hundred.

To convert bar to kPa, multiply by 100. So 1 bar is 100 kPa, 2.5 bar is 250 kPa and 0.5 bar is 50 kPa. It is exact because 1 bar is defined as 100,000 pascals and 1 kPa is 1,000 pascals.

How to use the converter

1. Type the amount in the Bars (bar) box. A decimal such as 2.5 or a fraction such as 3/4 works.
2. The big result shows Kilopascals (kPa). Use Decimals in the side column to fix the number of places.
3. The cards under the result give the same pressure in other units.
4. Type in the second box, or press the swap button, to convert kilopascals to bars instead.
5. Click a row in Common values to load it. Copy result, Copy link, Copy table and Print chart keep the answer. Start again resets the box.

Moving the decimal

Bar to kPa: move the decimal point two places to the right. 3.2 bar becomes 320 kPa. 0.07 bar becomes 7 kPa. Back to bar: two places left, so 450 kPa is 4.5 bar. For MPa move another three places left: 1 bar is 0.1 MPa.

The ladder of pressure units

Bar to kPa, a table

Worked examples

• A 1.01325 bar reading. That is exactly 101.325 kPa, one standard atmosphere.
• A system at 4.5 bar. 450 kPa, or 65.27 psi.
• A drop from 6 bar to 5.4 bar. 0.6 bar × 100 = 60 kPa lost.
• Back the other way. 250 kPa = 2.5 bar.

Where you see each unit

Bar appears on pumps, compressors, espresso machines and many European gauges. Kilopascals are the SI choice for weather, building and engineering documents. Because the factor is exactly 100, you can switch without any rounding: a 7 bar compressor limit is 700 kPa, and a 350 kPa rating is 3.5 bar. If a gauge shows both, check that its two scales agree with the factor of 100 before you trust it.

Gauge or absolute pressure

A tyre gauge, a pressure washer dial and most boiler gauges show gauge pressure, which is the pressure above the air around them. Absolute pressure counts from a perfect vacuum, so it is the gauge reading plus the air pressure. At one standard atmosphere, 101.325 kPa, 2 bar gauge is 3.01325 bar absolute, which is 301.325 kPa. The Gauge or absolute box above the tables does the sum in either direction. Air pressure changes with weather and height, so one standard atmosphere is only an average. The standard atmosphere is from NIST SP 811 Appendix B.8, checked 24 Oct 2026.

Where the numbers come from

NIST SP 811, Appendix B.8 lists 1 bar = 1.0 E+02 kPa and 1 standard atmosphere = 1.013 25 E+02 kPa. Checked 24 Oct 2026. The converter keeps the factors as exact fractions and rounds only the last digit shown. It is a unit converter, not a safety tool: for a tyre, boiler or tank, use the value printed on the equipment or in its manual.

Related pages: Bar to psi, Bar to atm, Psi to kPa and MPa to psi.