Convert kPa to psi kilopascals ↔ pounds per square inch Free Online Secure
Type a value in kilopascals and read it in pounds per square inch at once. The factor is exact by definition, the arithmetic happens in your browser, and nothing is sent anywhere.
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Common values — Convert kPa to psi (kilopascals ↔ pounds per square inch)
| kPa | psi |
|---|---|
| 1 | 0.14503773773 |
| 2 | 0.29007547546 |
| 3 | 0.435113213191 |
| 5 | 0.725188688651 |
| 10 | 1.4503773773 |
| 20 | 2.9007547546 |
| 50 | 7.25188688651 |
| 100 | 14.503773773 |
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
Where are kilopascals used?
In engineering, in Canadian weather reports and on the tyre placards of cars in many countries. A kilopascal is 1000 pascals, and standard atmospheric pressure is 101.325 kilopascals. A tyre pressure of 220 kilopascals is the same as 2.2 bar, which is why the two units appear side by side on car labels.
Is tyre pressure measured from zero or from the air around it?
From the air around it. A gauge reads gauge pressure — the amount above the surrounding atmosphere — so a tyre at 2.2 bar actually holds about 3.2 bar of absolute pressure. This page converts the numbers as given, without assuming one or the other, so a gauge reading in one unit converts to a gauge reading in the next.
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.
Kilopascals to psi: metric pumps, boilers and air lines for the American market
Machinery from Australia, New Zealand, Canada and much of Asia lists pressure in kilopascals. A US buyer, an importer or an installer following an American code expects psi. A boiler valve rated at 850 kPa, a pump delivering 400 kPa or an air line at 700 kPa must be translated before it is compared with local parts. To convert kPa to psi, multiply by 0.14504. That gives 100 kPa as 14.5 psi, 400 kPa as 58 psi and 1,000 kPa as 145 psi. The calculator above multiplies while you type, and the sections below set the numbers in a factory, a boiler room and a garden.
You will find the rule with worked examples, a profile of each unit, a comparison and many industrial and domestic cases, then the usual slips. All calculations happen in your browser. For safety, always use the rating printed on the equipment.
How to convert kPa to psi: multiply by 0.14504
The rule
One kPa is 0.1450377 psi, the reciprocal of 6.894757. To convert kPa to psi, multiply the kilopascals by 0.14504. That makes 250 kPa equal to 36.3 psi, 850 kPa equal to 123.3 psi and 10,000 kPa equal to 1,450 psi. To go back, multiply psi by 6.8948.
Worked examples
A hot-water relief valve of 850 kPa is rated at 123 psi. A compressor set at 700 kPa runs at 101.5 psi. A fire pump delivering 1,200 kPa gives 174 psi, and a hydraulic hose rated at 35,000 kPa withstands 5,076 psi.
Why the factor is exact
The factor follows from two exact definitions and has no hidden rounding. For rough work 0.145 is sufficient, within 0.03 per cent.
A quick sanity test
The answer in psi is almost seven times smaller than the number of kPa. If a “convert kPa to psi” calculation gave a larger number than you started with, you used the factor the wrong way round.
The kilopascal
The unit on metric equipment
The kilopascal equals a thousand pascals. Plumbing standards in Australia and New Zealand, Canadian weather reports and the data sheets of many Asian makers use it.
Where it appears
Data sheets, plumbing standards, forecasts and international product specifications.
Psi
The unit on American codes
Psi is the pressure unit written in American codes, on gauges and in contracts. Whatever a product's origin, a US customer will often want a rating in psi before accepting it.
Where it appears
American codes, gauges, purchase specifications and installers' manuals.
Kilopascals or psi?
One kPa is worth 0.145 psi, so the psi number is almost seven times smaller. 100 kPa is 14.5 psi and 700 kPa is 101.5 psi. The pressure is identical; only the scale changes.
The conversion is exact, with no hidden rounding. The trap is direction: from kPa to psi the figure falls.
Where the conversion shows up
Boilers and hot-water systems
A storage heater's relief valve at 850 kPa is rated at 123 psi, one at 1,000 kPa at 145 psi, and a heating boiler valve at 300 kPa at 43.5 psi. American inspectors expect to see psi on the tag. A “convert kPa to psi” calculation ensures the part complies.
Compressed air
A factory network at 700 kPa runs at 101.5 psi, and a nailer designed for 90 psi needs 620 kPa. If the regulator is in kPa and the tool in psi, one conversion is all that is needed to set it right.
Pumps
A pump curve that ends at 400 kPa shuts off at 58 psi, and one that delivers 250 kPa at its duty point delivers 36 psi. Pump data from Australia, Japan and Europe are often in kPa or metres of head; American catalogues use psi and feet of head.
Natural gas and LPG in homes
Domestic natural gas is supplied at about 1.1 kPa in Australia, 0.16 psi, and LPG regulators deliver 2.75 kPa, 0.4 psi. In America the figure is 0.25 psi for natural gas, 1.7 kPa, and 0.4 psi for propane, 2.8 kPa. Such small pressures show on a manometer in inches of water.
Weather and flying
Canadian forecasts quote pressure in kPa, where 101.3 kPa is 14.69 psi. Pilots in America set altimeters in inches of mercury, 29.92 at standard pressure, and elsewhere in hectopascals. The same air pressure thus appears in at least four units.
Steam and process heating
Low-pressure steam in a building runs at 35 to 100 kPa above atmosphere, 5 to 14.5 psi, and medium-pressure process steam at 700 to 1,000 kPa, 100 to 145 psi. American steam tables list psig, while Commonwealth tables list kPa.
Air conditioning
A split air conditioner with R32 shows suction pressures near 900 kPa, 130 psi, and discharge near 2,700 kPa, 390 psi, at normal conditions. Gauge sets for technicians display both psi and kPa scales for each refrigerant.
Hydraulic hoses and fittings
A hydraulic hose with a working pressure of 21,000 kPa works at 3,046 psi. Its burst pressure is usually four times that, 84,000 kPa, 12,184 psi. American catalogues state both in psi, and an importer should check the ratio against the original.
The mental shortcut
To convert kPa to psi in your head, divide by 7 and add 1.5 per cent. For 700 kPa: 100 plus 1.5 gives 101.5. For 345 kPa: 49.3 plus 0.7 gives 50.0. The error is under 0.1 psi for ordinary values.
Spreadsheet formulas
To convert kPa to psi in a spreadsheet, put the pressures in kPa in column A and enter =A2*0.1450377 in column B. For the reverse, =B2/0.1450377. A column with =A2/100 gives bar for quick comparison.
Rounding for safety
When you convert kPa to psi for a maximum rating, round down: 700 kPa is 101.5 psi, so write 101 psi and not 102. For a minimum operating value round up. The right rounding protects the user, not just the arithmetic.
Landmarks to memorise
70 kPa is 10 psi. 140 kPa is 20 psi. 210 kPa is 30 psi. 345 kPa is 50 psi. 690 kPa is 100 psi. 1,000 kPa is 145 psi. 2,000 kPa is 290 psi. To convert kPa to psi by eye, interpolate between them.
Reference ladder
101.325 kPa is 14.696 psi. 150 kPa is 21.76 psi. 220 kPa is 31.91 psi. 400 kPa is 58.02 psi. 850 kPa is 123.28 psi. 1,500 kPa is 217.56 psi. 2,000 kPa is 290.08 psi. 20,000 kPa is 2,900.8 psi. A ladder like this makes checks easy.
Checking by reversing
To check a “convert kPa to psi” calculation result, multiply the answer by 6.8948. If 345 kPa became 50.04 psi, then 50.04 times 6.8948 returns 345. A second test is size: the psi figure should be nearly seven times smaller.
Firefighting
A fire pump delivers 1,000 to 1,500 kPa, 145 to 218 psi, at the outlet. A hose nozzle works best at 700 kPa, 101.5 psi. Fire services in America speak of nozzle pressure in psi, while Australian ones use kPa, so training material needs both.
Link to bar and head
One kPa is 0.01 bar and corresponds to 0.102 metres, 0.335 feet, of water head. A pressure of 345 kPa is 3.45 bar and a head of 35.2 metres, 115 feet. Pump makers on both sides often give head and pressure together.
A worked example
An Australian pump is rated at 450 kPa and an American hose at 100 psi. Converting, 450 kPa is 65.3 psi, so the hose has a margin of 35 psi, 54 per cent. The pump and hose can be combined safely if the margin is enough under the local code.
Gauge and absolute pressure
A gauge normally shows pressure above the atmosphere. Absolute pressure is greater by 101.3 kPa, 14.7 psi. A reading of 400 kPa is 501 kPa absolute, 72.7 psi absolute. Calculations with the gas law need the absolute number.
Altitude corrections
At 1,000 metres the air pressure is 89.9 kPa, 13.0 psi, and at 2,000 metres 79.5 kPa, 11.5 psi. A compressor rated at sea level delivers less air at altitude, and a vessel rated by absolute pressure should be checked against these values.
Pressure test certificates
A test certificate for a pressure vessel reads, for example, "test pressure 1,500 kPa". In psi, 217.6. American inspectors often want psi on the same document. A “convert kPa to psi” calculation placed on the certificate itself, with both units, avoids queries.
Air tools and compressors
A tool maker states "6.3 bar" or "630 kPa" and an American one "90 psi", all the same pressure: 630 kPa is 91.4 psi. Standardised tests of air tools use 90 psi, 620 kPa, as the reference pressure.
Gas springs
The gas spring that holds up a tailgate contains nitrogen at about 10,000 kPa, 1,450 psi. Because of this stored pressure, gas springs must not be drilled or heated. The pressure is seldom printed, and the force rating in newtons is the figure used for replacement.
Water mains in cities
Mains pressure in towns runs at 300 to 700 kPa, 43.5 to 101.5 psi. Codes limit domestic supply to 500 kPa, 72.5 psi, and ask for pressure reducers above that. Utility documents in the Commonwealth give kPa, American ones psi.
Hot-air balloons and gas burners
The propane burner of a hot-air balloon is fed at 700 to 1,000 kPa, 101 to 145 psi, from tanks, and the pressure drops as fuel is used. Pilots watch the gauge in psi in the United States and in bar or kPa elsewhere.
Two routes to one answer
You can go from kPa to psi directly with 0.14504, or through bar: divide by 100 and multiply by 14.5038. If the results differ, a digit has been copied wrongly.
Welding and cutting gases
An oxygen regulator for welding is set to 200 to 300 kPa for light work, 29 to 43.5 psi, and an acetylene regulator must not exceed 100 kPa, 14.5 psi, because acetylene becomes unstable above that pressure. Welding charts in America quote psi, which is why the 15 psi limit is so well known.
Plumbing fixtures
A shower mixer rated for 50 to 500 kPa, 7 to 72.5 psi, works with typical household water. American fixtures say "20 to 80 psi", 138 to 552 kPa. A “convert kPa to psi” calculation shows at a glance that a fixture bought in one country suits the other.
Paint and coating equipment
An airless paint sprayer is rated at 20,000 kPa, 2,900 psi, and a low-pressure gun at 200 kPa, 29 psi. The first can inject paint into skin if it is mishandled, a reason why its pressure rating is printed prominently. A buyer abroad must read the number in both units.
Dust collectors and fans
A dust-collection fan produces a static pressure of 2.5 kPa, 0.36 psi, or about 10 inches of water. Industrial fans are rated in kPa, Pa or inches of water gauge, and the numbers are small compared with those of a compressor.
Tyre pressure in Asia and Oceania
Car manuals from Japan or Australia give tyre pressures such as 230 kPa or 250 kPa, which on an American pump are 33.4 or 36.3 psi. Japanese manuals sometimes give kgf/cm², where 2.3 is 225.5 kPa or 32.7 psi. A “convert kPa to psi” calculation through kPa is the safest route.
Water filters and softeners
A household water filter lists its maximum working pressure as 860 kPa, 125 psi, and a minimum of 140 kPa, 20 psi. A water softener works between 140 and 830 kPa, 20 to 120 psi. Because house pressure in many places is 300 to 500 kPa, 43.5 to 72.5 psi, these devices suit almost every supply, but a “convert kPa to psi” calculation avoids surprises where pressure is high.
Compressed-air storage on a worksite
A portable receiver of 100 litres at 1,000 kPa, 145 psi, holds 1,000 litres of free air, enough to run a small nailer for a few minutes. Safety rules in America demand that the vessel carries a plate in psi, and the Australian standard requires a plate in kPa. Importers often label both, and the same value must be calculated carefully.
Pneumatic cylinders
A pneumatic cylinder of 50 mm bore at 600 kPa gives a force of about 1,178 N. In psi the supply is 87 psi, and the American force is 265 lbf. Catalogues from Japan and Europe list kPa and newtons; American ones list psi and pounds-force.
Fuel injection
A petrol engine with port injection uses a fuel rail at 300 to 400 kPa, 43.5 to 58 psi. A diesel common rail operates at 160,000 to 250,000 kPa, 23,000 to 36,000 psi. A gauge on a service tool will read in one unit or the other, and the chart in the manual should be in the same.
Brake boosters
A brake servo uses engine vacuum of 60 to 70 kPa below atmospheric, 8.7 to 10.2 psi. If the vacuum fails the pedal gets stiff. Vacuum gauges in American workshops read in inches of mercury, where 60 kPa is 18 inHg.
Refrigeration
An R134a refrigeration circuit shows 150 to 350 kPa, 22 to 51 psi, on the low side and 1,000 to 1,700 kPa, 145 to 247 psi, on the high side. Pressure-temperature charts in psi are standard in American service manuals, and kPa charts are used in Australia.
Swimming pools
A pool pump generates 70 to 150 kPa on the filter gauge, 10 to 22 psi. When the pressure rises by 50 kPa, 7.3 psi, above its clean value, the filter needs backwashing. Pool equipment from Australia is marked in kPa, and American equipment in psi.
Garden irrigation
An irrigation valve is typically rated at 1,000 kPa, 145 psi, and household supply is 300 to 500 kPa, 43.5 to 72.5 psi. Drip systems want only 100 to 200 kPa, 14.5 to 29 psi, so a pressure reducer is fitted.
More values for convert kPa to psi
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 kPa = 0.0145038 psi
- 0.5 kPa = 0.0725189 psi
- 3 kPa = 0.435113 psi
- 4 kPa = 0.580151 psi
- 7 kPa = 1.01526 psi
- 15 kPa = 2.17557 psi
- 20 kPa = 2.90075 psi
- 75 kPa = 10.8778 psi
- 200 kPa = 29.0075 psi
- 500 kPa = 72.5189 psi
- 2,000 kPa = 290.075 psi
- 10,000 kPa = 1,450.38 psi
Mistakes to avoid with a “convert kPa to psi” calculation
The wrong factor
To go from kPa to psi, multiply by 0.14504. If 345 kPa came out as 2,379, you used 6.8948.
kPa read as bar
A bar is 100 kPa. Treating 345 kPa as 345 bar puts the pressure a hundred times too high. Check the unit before setting a regulator.
Gauge versus absolute
Only add 101.3 kPa or 14.7 psi when the specification calls for absolute pressure.
Questions in brief
What is the rule for a “convert kPa to psi” calculation?
psi equals kPa times 0.14504.
What is 100 kPa in psi?
14.5 psi.
What is 345 kPa in psi?
50.04 psi.
What is 1 psi in kPa?
6.8948 kPa.
Is my input uploaded?
No, everything is computed in your browser.
Related pages and a summary
You may also want Convert bar to psi, Convert psi to bar, Convert km to mi, Convert mi to km, Convert °C to °F, Convert °F to °C, Convert mm to m, Convert gal/min to L/min, Convert MPG (UK) to L/100km. For the opposite direction, see Convert psi to kPa.
Summing up: multiply kPa by 0.14504 to get psi, and keep the unit with the number. Everything stays in your browser, with no account and no upload.