How many psi is 2.4 bar?

About 34.8 psi. One bar is 14.5038 psi, so multiply bar by 14.5 for a close mental estimate and use the exact figure when you are near the edge of a load rating.

How much does tire pressure drop in cold weather?

Roughly one psi for every 10 °F, or about 0.07 bar per 5 °C. The exact figure depends on the starting pressure, because the gas law works on absolute pressure — this tool applies the real relationship rather than the rule of thumb.

Should I inflate tires hot or cold?

Cold, meaning the car has stood for at least three hours or driven less than a mile. A warm tyre reads several psi high, so setting it to the placard figure while hot leaves it under-inflated once it cools.

What is kgf/cm² on a tire gauge?

Kilogram-force per square centimetre, an older metric unit still printed on Japanese placards and some workshop gauges. It is close to bar but not identical — 1 kgf/cm² equals 0.9807 bar.

Is the pressure I type sent anywhere?

No. Every conversion is arithmetic done in your browser, so nothing you enter leaves your device.

Tire Pressure Converter

Convert tire pressure between psi, bar, kPa and kgf/cm², and see what a cold morning does to the reading.

The Tire Pressure Converter runs entirely in your browser. Pressures and temperatures you type are converted on your device and never uploaded.

Open the Tire Size Calculator

About Tire Pressure Converter

Door placards, gauges and tyre shops rarely agree on units. A European car quotes bar, a Japanese one kPa, an American gauge reads psi, and older manuals still print kgf/cm². This converter moves a pressure between all four at once, so you can set 2.4 bar on a gauge that only shows psi without doing mental arithmetic at the forecourt. The second half handles the question that catches people out every autumn: pressure falls as the air cools. Because tyre pressure is gauge pressure, the correction has to run through absolute pressure and absolute temperature rather than a rule of thumb, and that is exactly what happens here.

Features

Converts between psi, bar, kPa and kgf/cm² at the same time
Shows every unit at once, so you can read whichever your gauge uses
Temperature correction using the gas law on absolute pressure
Works out what a pressure set on a warm day reads on a cold morning
Backs a hot reading down to its cold-inflation equivalent
Compares a reading with the placard pressure and says which way to correct
Each unit is rounded the way that unit is normally quoted
One-click copy of the full conversion table

How to use the Tire Pressure Converter

Type the pressure you have and pick the unit it is in
Read the same pressure in psi, bar, kPa and kgf/cm²
Switch to temperature mode to see how the reading moves with the weather
Enter the placard pressure to check whether you are under or over

Example

Input

2.4 bar set at 20 °C

Output

34.8 psi · 240 kPa · 2.45 kgf/cm²
At 0 °C the same tyre reads 33.6 psi

A twenty-degree drop takes more than a psi out of the tyre — which is why the warning light appears on the first cold morning.

Common errors & troubleshooting

The gauge reads high right after driving. — That is normal. Tyres warm up in use and gauge pressure rises with them. Set pressure cold, or use the hot-to-cold mode here to work out what the tyre would read after standing.
The tyre placard and the sidewall disagree. — Use the placard. The number moulded into the sidewall is the maximum the tyre may be inflated to, not the pressure the car was designed around.
kPa and kgf/cm² look almost the same. — They are not: 1 kgf/cm² is about 98 kPa, so 2.4 kgf/cm² is 235 kPa, not 240. Both are shown separately here for that reason.

Frequently asked questions

How many psi is 2.4 bar?: About 34.8 psi. One bar is 14.5038 psi, so multiply bar by 14.5 for a close mental estimate and use the exact figure when you are near the edge of a load rating.
How much does tire pressure drop in cold weather?: Roughly one psi for every 10 °F, or about 0.07 bar per 5 °C. The exact figure depends on the starting pressure, because the gas law works on absolute pressure — this tool applies the real relationship rather than the rule of thumb.
Should I inflate tires hot or cold?: Cold, meaning the car has stood for at least three hours or driven less than a mile. A warm tyre reads several psi high, so setting it to the placard figure while hot leaves it under-inflated once it cools.
What is kgf/cm² on a tire gauge?: Kilogram-force per square centimetre, an older metric unit still printed on Japanese placards and some workshop gauges. It is close to bar but not identical — 1 kgf/cm² equals 0.9807 bar.
Is the pressure I type sent anywhere?: No. Every conversion is arithmetic done in your browser, so nothing you enter leaves your device.

Related tools

Tire Size Calculator — Decode a tire size and compare two sizes for diameter and speedo error.
Fuel Economy Converter — Convert between MPG (US), MPG (UK), L/100km and km/L, with trip fuel and cost.
Gas Mileage Calculator — Calculate MPG or L/100km from distance and fuel used, and convert.
Braking Distance Calculator — Stopping distance from speed, reaction time and road surface — thinking plus braking.
Unit Conversion Calculator — Convert length, weight, temperature, volume, area, speed and more.
Fuel Cost Calculator — Estimate the fuel cost of a trip from distance, efficiency and price.