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Multiple conversions
To convert a pressure from kilopascals (kPa) to pascals (Pa), multiply by 1,000.
The kilo prefix means one thousand, so the conversion is an exact three-place decimal shift. Divide by 1,000 to go from Pa back to kPa.
A ventilation design states the available duct pressure as 0.35 kPa, but the fan manufacturer's performance curve is plotted in pascals:
Reading the curve at 350 Pa gives the deliverable airflow directly, with no further conversion.
| kPa | Pa |
|---|---|
| 0.1 | 100 |
| 0.35 | 350 |
| 1 | 1,000 |
| 6.9 | 6,900 |
| 101.325 | 101,325 |
| 250 | 250,000 |
Pa and kPa are the same unit at two working scales, and each owns a territory. The plain pascal rules where pressures are small and differential: duct static pressure, wind load on façades (a 100 km/h wind exerts roughly 480 Pa), filter pressure drops, acoustics. The kilopascal rules where pressures approach or exceed atmospheric: process piping, tire inflation (a road-car tire is about 220 kPa), soil bearing capacity, steam tables. Documents constantly cross the line — a wind-load standard hands a façade engineer 1.2 kPa while the pressure-test rig reads 1,200 Pa — so the ×1,000 shift is among the most-performed conversions in mechanical and civil engineering. It is also among the most silently fumbled: because both units are "metric pressure," a dropped k survives review more easily than a wrong unit would, and the resulting thousandfold error can hide until a sanity check catches it. The reliable guard is an anchor value: atmospheric pressure is 101 kPa and 101,325 Pa. Any conversion that moves a number across that landmark in the wrong direction announces itself immediately.
To convert from kilopascal (kPa) to megapascal (MPa), use the following formula:
megapascal (MPa)
= 11000× kilopascal (kPa)
= 0.001× kilopascal (kPa)
To convert from kilopascal (kPa) to hectopascal (hPa), use the following formula:
hectopascal (hPa)
= 10× kilopascal (kPa)
To convert a pressure from kilopascals (kPa) to millibars (mbar), multiply by 10.
One kilopascal is 1,000 Pa and one millibar is exactly 100 Pa, so the ratio is a clean factor of ten. Standard sea-level pressure makes the anchor easy to remember: 101.325 kPa = 1,013.25 mbar.
A vacuum-drying recipe specifies a chamber pressure of 85 kPa absolute, but the chamber's controller displays millibars:
The controller setpoint is 850 mbar; the 163 mbar below the 1,013 mbar ambient is the gentle vacuum the recipe relies on.
| kPa | mbar |
|---|---|
| 0.1 | 1 |
| 10 | 100 |
| 50 | 500 |
| 85 | 850 |
| 101.325 | 1,013.25 |
| 200 | 2,000 |
This direction of the conversion is mostly driven by equipment. A great deal of vacuum and low-pressure instrumentation — chamber gauges, leak detectors, freeze-dryer and CVD controllers, European weather instruments — reads out in millibars, while calculations, standards and data sheets on the same bench are written in kilopascals. So the kPa figure from a psychrometric chart, a boiling-point table or a process simulation gets multiplied by ten on its way to the instrument panel. Aviation provides a second, subtler case: altimeter settings in most of the world are given in hectopascals, and since 1 hPa = 1 mbar exactly, a kPa value from a standard-atmosphere table converts to the QNH field by the same ×10. The factor is trivial by design — the bar was defined as 100,000 Pa precisely so that metric pressure units would interconvert by powers of ten — which leaves only one real failure mode: sliding the decimal the wrong way. Remember that mbar values are the big numbers (ambient ≈ 1,000) and kPa values the small ones (ambient ≈ 100), and the direction of the shift checks itself.
To convert a pressure from kilopascals (kPa) to bar, divide by 100 — that is, multiply by 0.01.
The factor is exact: one bar is defined as 100,000 Pa = 100 kPa, so the conversion is a two-place decimal shift with no rounding anywhere.
A Japanese-market tire placard specifies 240 kPa and a European pressure gauge is marked in bar:
| kPa | bar |
|---|---|
| 10 | 0.1 |
| 100 | 1 |
| 101.325 | 1.01325 |
| 220 | 2.2 |
| 250 | 2.5 |
| 500 | 5 |
| 700 | 7 |
| 1,000 | 10 |
Since the arithmetic cannot go wrong except by misplacing the decimal, the value of this page is mostly the anchors: 100 kPa is one bar almost exactly one atmosphere (the true atmosphere is 101.325 kPa = 1.01325 bar, 1.3% higher); typical car tires run 220–250 kPa = 2.2–2.5 bar; European shop air is 600–700 kPa = 6–7 bar; a 200-bar scuba or industrial gas cylinder is 20,000 kPa, which is where kPa's readability gives out and bar (or MPa — 20 MPa) takes over. That readability boundary is the practical reason both units persist: kPa keeps everyday pressures in comfortable two-to-three-digit numbers, bar keeps high pressures compact. The reference-frame rule is unchanged — kPa gauge becomes bar gauge; nothing about dividing by 100 adds or removes the atmosphere. And when documents from mixed sources land on one desk, remember the sibling shifts: 1 bar is also 1,000 mbar and 0.1 MPa, so a spec sheet hopping between mbar, kPa, bar and MPa is doing nothing but sliding one decimal point around.
To convert from kilopascal (kPa) to torr (torr), use the following formula:
torr (torr)
= 760000101325× kilopascal (kPa)
= 7.500616827041697508× kilopascal (kPa)
To convert from kilopascal (kPa) to meter of water @ 4°C (mH2O), use the following formula:
meter of water @ 4°C (mH2O)
= 19.80665× kilopascal (kPa)
= 0.10197162129779282426× kilopascal (kPa)
To convert a pressure from kilopascals (kPa) to millimeters of mercury (mmHg), multiply by 7.5006.
The conventional millimeter of mercury is defined as exactly 133.322 Pa, and dividing 1,000 by 133.322 gives 7.50064. For mental arithmetic, 1 kPa ≈ 7.5 mmHg is accurate to better than 0.01%, and the atmosphere anchors the scale: 101.325 kPa = 760 mmHg.
A physiology paper reports an oxygen partial pressure of 13.3 kPa, and a clinician used to conventional units wants it in mmHg:
The reported value is simply normal arterial PaO₂ (~100 mmHg) written in SI.
| kPa | mmHg |
|---|---|
| 1 | 7.5 |
| 5.3 | 40 |
| 10.7 | 80 |
| 13.3 | 100 |
| 16 | 120 |
| 101.325 | 760 |
Most conversions modernize old units into SI; this one runs the other way, because two large professions still think in mercury. Medicine is the first: blood pressure cuffs, ventilator readouts, blood-gas reports in North America, and every clinician's memorized normal ranges (120/80, PaCO₂ 40) are mmHg, so SI-formatted values from European journals and laboratory systems get multiplied by 7.5 before intuition can engage. Vacuum technology is the second: rough-vacuum work quotes torr — identical to mmHg for practical purposes — so a process chart specifying 2.5 kPa becomes about 19 torr at the pump gauge. The factor 7.5 is friendly enough that estimation usually suffices, and the two round anchors (100 kPa ≈ 750 mmHg, 13.3 kPa ≈ 100 mmHg) bracket nearly every realistic value in both fields. One caution when precision matters: mmHg is defined via mercury's density at 0 °C under standard gravity, so a mercury column at room temperature reads about 0.3% off the conventional unit — negligible clinically, but relevant when calibrating barometers.
To convert a pressure from kilopascals (kPa) to pounds per square inch (psi), multiply by 0.14504.
One psi is 6,894.76 Pa, so a kilopascal is 1,000 ÷ 6,894.76 = 0.1450377 psi. The reverse factor is the one worth memorizing, because it is nearly a round number: 1 psi ≈ 6.895 kPa. For mental estimates, dividing the kilopascal value by 7 lands within 1%.
Two anchors bracket almost every pressure a gauge will show:
A European car's door placard specifies 220 kPa cold tire pressure, and the gauge at a US filling station reads in psi:
Round to 32 psi and the tire is correctly inflated. The placard and the gauge never disagreed — only their units did.
| kPa | psi |
|---|---|
| 1 | 0.145 |
| 100 | 14.50 |
| 101.325 | 14.696 |
| 200 | 29.01 |
| 220 | 31.91 |
| 250 | 36.26 |
| 700 | 101.5 |
The kPa is the pressure unit of the metric world's paperwork and the psi is the unit of its hardware, which is why this particular conversion outnumbers every other pressure conversion in daily use. Vehicle tire placards in Europe, Japan, Australia and Canada are printed in kPa, while tire gauges, compressor regulators and inflator displays sold across North America read psi — so the conversion happens at petrol stations several million times a day. Industrial pneumatics repeat the pattern: a machine's datasheet specifies 600 kPa supply air, the shop's regulator is marked 87 psi, and both describe the same 6 bar line. Medical and laboratory equipment adds a third venue, with oxygen regulators and autoclave cycles specified in kPa but serviced with psi instruments.
One distinction does real damage when overlooked. Most psi readings on equipment are psig — gauge pressure, measured relative to the surrounding air — while kPa figures in scientific and meteorological contexts are frequently absolute (psia is the imperial equivalent). The multiplication by 0.14504 is identical for both, but mixing the two shifts an answer by a full atmosphere: 200 kPa absolute is 29.0 psia, which is only 14.3 psig on a tire gauge. Stating which frame a number belongs to costs one word and prevents the error entirely.
To convert from kilopascal (kPa) to kilopound per square inch (ksi), use the following formula:
kilopound per square inch (ksi)
= 0.00014503768078× kilopascal (kPa)
With 0.00014503768078 is the ratio between the base units kilopound per square inch (ksi) and kilopascal (kPa).
To convert pressure from kilopascals (kPa) to inches of mercury (inHg), multiply by 0.2953.
The factor follows from the definition of the inch of mercury: a 1-inch (25.4 mm) column of mercury at 0 °C exerts 3.386389 kPa, and 1 ÷ 3.386389 = 0.295300. For quick mental arithmetic, "multiply by 0.3" gets you within 1.6%.
The anchor every pilot and meteorologist knows:
A Canadian weather service reports station pressure of 98.6 kPa, and a US-built altimeter needs the setting in inHg:
Reverse direction: multiply by 3.38639 — an altimeter setting of 30.15 inHg is 102.10 kPa.
| kPa | inHg |
|---|---|
| 90 | 26.58 |
| 95 | 28.05 |
| 98 | 28.94 |
| 100 | 29.53 |
| 101.325 | 29.92 |
| 103 | 30.42 |
| 105 | 31.01 |
This conversion sits on the border between metric and US customary practice. Aviation is the biggest user: altimeter settings are broadcast in inHg in the United States but in hectopascals (= 0.1 kPa) almost everywhere else, so crews crossing borders convert constantly — and the table above doubles as an hPa table if you multiply the kPa column by 10. Weather reporting in US media quotes barometric pressure in inHg, while scientific data arrives in kPa or hPa. Finally, HVAC and automotive vacuum work in North America measures manifold and refrigerant-line vacuum in inHg. A note for accuracy: this page uses the 0 °C (32 °F) mercury column definition, the one used in aviation and meteorology; a "60 °F inch of mercury" also exists in some US gas-industry contexts and differs by about 0.5%.
A kilopascal (kPa) is a metric unit of pressure that equals 1,000 pascals.
It is one of the most common units for measuring pressure worldwide, used in both scientific and everyday applications.
The base unit, the pascal (Pa), is named after the French polymath Blaise Pascal.
As part of the metric system (also known as the SI system), the kilopascal is widely used in scientific, engineering, and industrial fields due to its standardization and ease of calculation.
The kPa unit is used to measure pressure in many everyday and technical contexts. Common examples include:
For practical use, it's essential to understand how kPa converts to other common pressure units.