Convert psi to kPa

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Enter a pressure in psi and read the result in kilopascals. One psi is 6.895 kPa, so 35 psi comes to 241.32 kPa. The tables give 58 ready conversions and tire pressures with the warning threshold under the US standard, and a step-by-step guide covers the spreadsheet formula.

psi
kPa
to

What is psi, and what is a kilopascal?

Psi is short for pound-force per square inch. The unit describes the pressure produced when a force of one pound acts on an area of one square inch[1].


A pound-force is the weight of a mass of one pound, which is exactly 0.45359237 kilograms. The weight is taken at standard gravity, 9.80665 m/s²[2]. That definition and the length of the inch give the value that the NIST conversion table lists as 6.894757 kPa[3].


Psi remains in widespread use in the United States and Canada, for example for tire pressure[4].


A kilopascal, in turn, is a thousand pascals, and the pascal is the SI unit of pressure equal to one newton per square meter[5].

Oil pressure gauge with a scale from 0 to 100 pounds per square inch on a red housing
An oil pressure gauge with a scale in pounds per square inch, marked from 0 to 100. The top of that scale is 689.48 kPa. Photo: hidde schalm, Unsplash.

How many kPa is one psi?

One psi is 6.894757 kPa. To convert psi to kilopascals, multiply the number of psi by this value from the NIST conversion table[3]. The result in kilopascals is therefore almost seven times the number of psi.


English Wikipedia gives 32 psi as a common gauge pressure for a car tire[1], which converts to 220.63 kPa. A value of 30 psi is 206.84 kPa. A value of 35 psi equals 241.32 kPa.


The converter multiplies as you type and shows the result to hundredths of a kilopascal. The field also accepts decimals, so 32.5 psi becomes 224.08 kPa. With small values the result has more decimal places, so half a psi shows as 3.447 kPa.


Tire pressure values are gauge pressure by convention[4]. The multiplication keeps the type of pressure, so gauge pressure from a gauge gives gauge pressure in kilopascals, and absolute pressure gives absolute pressure. Converting one into the other is shown in the example of 35 psi in absolute kilopascals.

How do you convert psi to kPa? Formula and example

Formula: kPa = psi × 6.894757


Take 44 psi. Multiplying by 6.894757 gives 303.37 kPa.


The figure of 44 psi also appears in the US standard FMVSS 138. Among the maximum inflation pressures of P-metric standard load tires, the standard lists 44 psi and writes 300 kPa next to it[6]. The two figures in the standard are therefore 3.37 kPa apart.


For the other direction, from kilopascals to psi, use the kPa to psi converter, and the psi to bar converter gives the value in bar.

How many kPa is a given number of psi?

The table covers values from 0.5 to 6,000 psi. Results are rounded the same way as in the converter’s result field: to hundredths of a kilopascal, and to four significant digits when the result is below ten.
PsiKilopascals
0.5 psi3.447 kPa
1 psi6.895 kPa
2 psi13.79 kPa
3 psi20.68 kPa
4 psi27.58 kPa
5 psi34.47 kPa
6 psi41.37 kPa
7 psi48.26 kPa
8 psi55.16 kPa
10 psi68.95 kPa
12 psi82.74 kPa
14 psi96.53 kPa
14.7 psi101.35 kPa
15 psi103.42 kPa
20 psi137.9 kPa
22 psi151.68 kPa
25 psi172.37 kPa
26 psi179.26 kPa
28 psi193.05 kPa
29 psi199.95 kPa
30 psi206.84 kPa
31 psi213.74 kPa
32 psi220.63 kPa
33 psi227.53 kPa
34 psi234.42 kPa
35 psi241.32 kPa
36 psi248.21 kPa
37 psi255.11 kPa
38 psi262 kPa
40 psi275.79 kPa
42 psi289.58 kPa
43.5 psi299.92 kPa
44 psi303.37 kPa
45 psi310.26 kPa
50 psi344.74 kPa
55 psi379.21 kPa
58 psi399.9 kPa
60 psi413.69 kPa
65 psi448.16 kPa
70 psi482.63 kPa
75 psi517.11 kPa
80 psi551.58 kPa
90 psi620.53 kPa
100 psi689.48 kPa
110 psi758.42 kPa
120 psi827.37 kPa
125 psi861.84 kPa
130 psi896.32 kPa
150 psi1,034.21 kPa
200 psi1,378.95 kPa
250 psi1,723.69 kPa
300 psi2,068.43 kPa
500 psi3,447.38 kPa
1,000 psi6,894.76 kPa
2,000 psi13,789.51 kPa
3,000 psi20,684.27 kPa
5,000 psi34,473.79 kPa
6,000 psi41,368.54 kPa

At what pressure does the warning light come on in a US car?

The US standard FMVSS 138 requires the low tire pressure warning light to come on when tire pressure falls to 25 percent below the vehicle manufacturer’s recommended cold inflation pressure[6]. If that threshold is lower than the minimum in the standard’s table, the minimum applies. For P-metric standard load tires the minimum is 140 kPa, or 20 psi. The table starts at 28 psi, because from that value a 25 percent drop gives a threshold above the minimum in both units.
Recommended pressureKilopascalsWarning at (psi)Warning at (kPa)
28 psi193.05 kPa21 psi144.79 kPa
29 psi199.95 kPa21.75 psi149.96 kPa
30 psi206.84 kPa22.5 psi155.13 kPa
31 psi213.74 kPa23.25 psi160.3 kPa
32 psi220.63 kPa24 psi165.47 kPa
33 psi227.53 kPa24.75 psi170.65 kPa
34 psi234.42 kPa25.5 psi175.82 kPa
35 psi241.32 kPa26.25 psi180.99 kPa
36 psi248.21 kPa27 psi186.16 kPa
37 psi255.11 kPa27.75 psi191.33 kPa
38 psi262 kPa28.5 psi196.5 kPa
39 psi268.9 kPa29.25 psi201.67 kPa
40 psi275.79 kPa30 psi206.84 kPa
41 psi282.69 kPa30.75 psi212.01 kPa
42 psi289.58 kPa31.5 psi217.18 kPa
44 psi303.37 kPa33 psi227.53 kPa
Example from the table: with a recommendation of 35 psi, the warning light must come on once the pressure falls to 26.25 psi. In kilopascals that threshold is 180.99 kPa.

Which number formats does this converter accept?

The table shows what the field does with the ways a pressure usually reaches it from gauges, tires and spreadsheets. The converter itself calculated every result.
What you typeWhat the converter showsNote
35241.32 kPaA plain number is read as psi, because that’s what the field is labeled.
35 psi241.32 kPaThe psi symbol pasted along with the number is skipped, in capitals too.
35 psig241.32 kPaThe psig suffix marks a gauge reading. The field skips it, and the result stays gauge pressure, only in kilopascals.
14.7 psia101.35 kPaThe psia suffix marks absolute pressure. The field skips it, so the result is in absolute kilopascals.
2.4 bar240 kPaA pressure in bar is converted by the field itself, first to psi and then to kilopascals.
2.517.24 kPaThe period is your decimal point, and that’s exactly how we read it.
2,517.24 kPaA comma with fewer than three digits after it is a decimal comma from a European document, so we read two and a half psi.
1.50010.34 kPaA single period is always read as a decimal point, so the field takes one and a half psi. A note under the field says: Read as 1.5. If you meant 1500, type 1500.
1,50010342.14 kPaA comma followed by three digits groups thousands, so the field reads fifteen hundred psi. A note under the field says: Read as 1500. If you meant 1.5, type 1.5.
1/23.447 kPaA fraction with a slash is worked out for you, so half a psi doesn’t need to become 0.5 first.
-10-68.95 kPaA minus sign is accepted, so a vacuum gauge reading in psi converts too.
-80 kPa-80 kPaA value with the kPa symbol is recognized and comes back unchanged, minus sign included, as long as the minus sits right against the number.
- 80 kPaThe result field stays empty.A minus separated by a space isn’t joined to the number, so nothing is calculated. Type the minus right before the digit.

How do you convert psi to kPa in a spreadsheet?

For a single value the converter field is enough. A spreadsheet converts a whole column of pressures with one formula dragged down.

  1. Excel: the CONVERT function

    The syntax is CONVERT(number,from_unit,to_unit). Psi has the code "psi" and the pascal has the code "Pa". The prefix k can be added to any metric unit, so for a value in cell A1 you enter =CONVERT(A1,"psi","kPa")[7].

  2. Unit codes with the right capitalization

    Excel treats unit names and prefixes as case-sensitive[7]. The kilopascal code works as "kPa", with a lowercase k and a capital P, while "kpa" or "PSI" returns the #N/A error.

  3. Plain multiplication if you prefer no function

    The formula =A1*6.894757 uses the multiplier from the NIST conversion table and works in any spreadsheet, including Google Sheets and LibreOffice Calc.

  4. Checking the result on one cell

    Before you drag the formula down the column, enter 35 in cell A1. The result should start with 241.3165. Rounded to hundredths that is 241.32 kPa, the value in the 35 psi row of the table.

What is 35 psi in absolute kPa?

A reading of 35 psi from a gauge is 342.64 kPa in absolute kilopascals. The result comes from adding atmospheric pressure to 241.32 kPa of gauge pressure. For atmospheric pressure we use the standard atmosphere, which a 1954 resolution of the General Conference on Weights and Measures set at 101.325 kPa[8].


Gauge pressure is measured relative to ambient pressure, and absolute pressure relative to vacuum[4]. The difference shows up in the mountains. When a car drives higher, air pressure drops, so the gauge pressure in the tire rises, while the absolute pressure stays essentially unchanged[4].


NIST advises attaching information about the conditions of measurement to the name of the quantity and leaving the unit symbol without additions[9]. English Wikipedia notes that the letters in psia and psig are appended to the unit to show the zero reference, and that NIST discourages this practice[4].

How many kPa is a bike tire pumped in psi?

Trek’s pressure chart for its Bontrager tires lists every range in psi first and in bar second. The AW1 Hard-Case Lite road tire in 700x28 takes 80–115 psi, and the GR1 Comp gravel tire in 700x40 takes 30–50 psi[10].


In kilopascals, 80–115 psi is 551.58–792.9 kPa and 30–50 psi is 206.84–344.74 kPa. A road tire pumped to 100 psi therefore holds 689.48 kPa, and a gravel tire at 40 psi holds 275.79 kPa.

Convert other units to Kilopascals (kPa)

bar to kPa

Convert Pounds per square inch (psi) to other units

psi to atmpsi to bar

Sources

  1. Pound per square inch — Wikipedia
  2. Pound (force) — Wikipedia
  3. NIST Guide to the SI, Appendix B.9: Factors for units listed by kind of quantity or field of science — National Institute of Standards and Technology
  4. Pressure measurement — Wikipedia
  5. SI: A concise summary of the International System of Units — Bureau International des Poids et Mesures
  6. 49 CFR § 571.138 — Standard No. 138; Tire pressure monitoring systems — Legal Information Institute, Cornell Law School
  7. CONVERT function — Microsoft
  8. Resolution 4 of the 10th CGPM (1954): Definition of the standard atmosphere — Bureau International des Poids et Mesures
  9. NIST Guide to the SI, Chapter 7: Rules and Style Conventions for Expressing Values of Quantities — National Institute of Standards and Technology
  10. Bontrager tire pressures — Trek Bicycle
  11. UN Regulation No 141 — Uniform provisions concerning the approval of vehicles with regard to their Tyre Pressure Monitoring Systems (TPMS) — EUR-Lex

Every figure in the tables was computed from the unit definitions and checked arithmetically before publication. Historical values and the names of local units come from the sources listed above.

Content last reviewed: · written and checked by the Arteon team

Common questions about converting psi to kPa

Is 30 psi too low if the manufacturer recommends 34 psi?

Under FMVSS 138 the warning light for such a tire must come on once the pressure falls to 25.5 psi[6]. A pressure of 30 psi is above that threshold. It is still 4 psi, or 27.58 kPa, below the recommended 34 psi.

How do you convert psi to kPa in your head?

Multiply the number of psi by 6.9. The result comes out less than one tenth of a percent above the exact value. For 35 psi the mental calculation gives 241.5 kPa, and the converter shows 241.32 kPa.

Why does a tire gauge read zero when it is not connected?

A tire gauge measures gauge pressure, the difference from ambient pressure, so zero means a pressure equal to the air around it[4]. In absolute kilopascals the same state is about 101 kPa, because that is the standard atmosphere[8].

What is the difference between a kilopascal and a megapascal?

A megapascal is a thousand kilopascals, because the mega prefix means a million and kilo means a thousand[5]. For high pressures the megapascal figure is shorter. A pressure of 3,000 psi is 20,684.27 kPa. In megapascals that is 20.68 MPa.

Does the tire pressure warning work the same in Europe as in the US?

The thresholds differ. The US standard FMVSS 138 counts a 25 percent drop from the recommended cold inflation pressure[6]. UN Regulation No. 141 counts a 20 percent drop in operating pressure, with a minimum of 150 kPa[11]. A table of thresholds in kilopascals is on the kPa to psi converter page.

Arteon free tool screenshot: Convert psi to kPa

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