Kilopascals to pounds per square inch

What the units mean

Convert kilopascals (kPa) to pounds per square inch (psi) instantly in your browser. See the formula, a worked example and limits of the result.

Pressure expresses force distributed over an area. Kilopascals are common in SI-based engineering and weather reports; bar appears on equipment and tire gauges; psi remains widespread on US specifications. Converting the unit changes the number on the scale, but never the physical pressure being reported.

This page converts one named unit into another within the same physical or digital quantity. The input stays in the browser. The result is a change of representation: it does not estimate an unmeasured property, correct a label, or supply missing information about the object being measured. Identify the original unit before typing a number, especially when a symbol could have more than one informal meaning.

How to calculate

psi = kPa × 0.145037737730. Use the same pressure reference on both sides: gauge and absolute readings are not interchangeable.

Use the displayed relationship with the entered value in the source unit. For an ordinary linear conversion, multiply by the ratio of the source unit to the destination unit. The reverse direction divides by that same ratio. Fuel economy is the exception here: it uses a reciprocal, so the number appears in the denominator. The calculator carries the defined constants through the calculation before shortening the displayed decimal.

As a worked example, enter 100 kPa. The output is 14.503773773 psi. Put the unit beside both numbers when copying them into a document or spreadsheet. A number without its unit does not reveal the measurement scale, and switching the order of the units changes the operation. The example is illustrative; use the value from your own measurement for a real comparison.

When this conversion is useful

Tire and compressor specifications often cross between kPa and psi. Read the pressure at the same tire temperature and with the same gauge convention; heating after driving changes the actual pressure. When comparing a required minimum or maximum, keep enough digits before deciding whether the reading is inside the permitted interval.

Start with a figure explicitly reported in kilopascals (kPa) and read the answer in pounds per square inch (psi). A smaller or larger output number alone says nothing about whether the measured quantity has changed. If the original source gives a rounded value, the calculation cannot recover digits that were never measured. For a critical limit, compare using the unrounded numerical result and round only the final presentation.

Precision and common mistakes

Check whether the source is absolute pressure or gauge pressure before comparing readings. A gauge reading is measured relative to surrounding air; an absolute reading is measured relative to vacuum. A unit converter cannot infer or remove that offset. Negative gauge readings can represent a partial vacuum, whereas negative absolute pressure would be physically invalid.

Conversion factors can be defined exactly even when the decimal displayed on the page has been shortened. Values involving π are approximated by computer arithmetic; a stated measurement may have much greater uncertainty than that arithmetic. Carry the source unit and enough significant figures through intermediate steps. If you need a certified measurement, calibration or commercial settlement, use the applicable standard and the original instrument record.

Questions about the result

Why can a reverse conversion return a slightly different final digit? The visible result is rounded to make it readable; reversing that shortened number starts from a different input. Why does a plausible figure sometimes disagree with a product label? The label may use another convention, a different reference condition or fewer significant figures. Confirm the exact unit symbol and the measurement definition before deciding that either number is wrong.