Pressure Converter

Convert between pascals, bar, psi, atmospheres, mmHg, kPa, and torr — for tyres, weather, diving, vacuum, and engineering.

Pressure

Pa, bar, psi, mmHg

From

Result

0.001

1 Pa = 0.001 kPa

Popular conversions

What Is a Pressure Converter?

A pressure converter translates force-per-area readings between units — pascals to psi, bar to atmospheres, millimetres of mercury to kilopascals. Pressure is force divided by area, so the SI unit, the pascal (Pa), is one newton per square metre. Because a single pascal is tiny, real-world pressure is usually quoted in kilopascals, bar, psi, or atmospheres depending on the field.

This converter routes through the pascal using exact and standard ratios. It spans the everyday (tyre psi, weather hPa), the industrial (bar, kPa), the medical (mmHg for blood pressure), and the scientific (torr, atmospheres for vacuum and chemistry), so one reading can be read in whichever unit your gauge or instrument uses.

This is one category of the full Unit Converter — pair it with our percentage calculator or scientific calculator for related everyday maths.

How Pressure Conversion Works

Everything routes through the pascal

Each unit has a fixed pascal factor. The converter turns your input into pascals, then projects it into every other unit so the outputs stay consistent.

Pressure is force over area

1 Pa = 1 N/m². The same force on a smaller area gives more pressure, which is why a sharp heel can exert more pressure than an elephant's foot.

Bar and atmosphere are near-equal

1 bar = 100,000 Pa and 1 standard atmosphere = 101,325 Pa, so they differ by about 1.3%. Both approximate sea-level air pressure.

Gauge vs absolute pressure

Tyre and many industrial gauges read gauge pressure (above atmospheric); absolute pressure includes the ~1 atm baseline. The difference matters for vacuum and gas work.

Core Pressure Conversion Factors

Multiply to reach pascals; divide to come back. These are the most-used pressure bridges.

psi → Pa

× 6894.76

One pound per square inch is 6,894.76 pascals. The bridge between US and SI pressure.

bar → Pa

× 100000

One bar is exactly 100,000 pascals (100 kPa), close to one atmosphere.

mmHg → Pa

× 133.322

One millimetre of mercury (1 torr) is 133.322 pascals. Used for blood pressure and vacuum.

How to Use the Pressure Converter

1
Enter the pressure
Type the reading you want to convert — a tyre pressure, a weather value, a gauge or vacuum figure.
2
Choose the 'from' unit
Pick pascals, kPa, bar, psi, atmospheres, mmHg, or torr as your starting unit.
3
Choose the 'to' unit
Select the target unit, or swap the two to reverse direction.
4
Read every unit at once
The all-units table shows the pressure across psi, bar, kPa, atm, and mmHg simultaneously for a quick cross-check.

Key Pressure Concepts

Pascal

The SI unit of pressure: one newton per square metre. Small in everyday terms — atmospheric pressure is about 101,325 Pa — so kPa and bar are common.

Atmosphere (atm)

A reference unit equal to 101,325 Pa, the average air pressure at sea level. Standard in chemistry and diving (each 10 m of water adds ~1 atm).

psi

Pounds per square inch, the US standard for tyres and many industrial gauges. Car tyres run around 32 psi (2.2 bar / 220 kPa).

mmHg / torr

Millimetres of mercury, equal to one torr (133.3 Pa). Used for blood pressure (e.g. 120/80 mmHg) and vacuum measurement.

Real-World Pressure Conversions

🚗

Tyre pressure

32 psi is 2.2 bar or 220 kPa. Tyre placards and pumps mix psi, bar, and kPa, so converting keeps inflation correct.

🌦️

Weather pressure

1,013 hPa (millibar) is standard sea-level pressure, equal to 29.92 inHg. Barometers and aviation altimeters convert between these.

🩺

Blood pressure

A 120/80 reading is in mmHg, equal to about 16/10.7 kPa. Medicine sticks with mmHg by long convention.

🤿

Diving depth

At 10 m underwater the pressure is about 2 atm (202 kPa); at 30 m it's 4 atm. Dive tables work in atmospheres and bar.

🏭

Industrial gauges

A 10-bar process line is 145 psi or 1,000 kPa. Plants mix bar, kPa, and psi across equipment from different makers.

🔬

Vacuum systems

A vacuum of 1 torr is 133 Pa or 0.0013 atm. Lab and semiconductor vacuum work measures in torr and pascals.

Best Practices for Pressure Conversion

✓Know gauge vs absolute. Tyre and many gauges read pressure above atmospheric. If a calculation needs absolute pressure, add ~101.325 kPa (1 atm) to the gauge reading.
✓Don't confuse bar and atm. They're close (1.3% apart) but not equal: 1 bar = 100 kPa, 1 atm = 101.325 kPa. For precise work, keep them distinct.
✓Keep mmHg for medical readings. Blood pressure is universally in mmHg. Converting to kPa is valid but unconventional in a clinical context.
✓Watch hPa vs mbar in weather. Hectopascals and millibars are numerically identical (1 hPa = 1 mbar), so a 1,013 reading is the same in both — no conversion needed.
✓Mind temperature for gas pressure. Gas pressure depends on temperature (the gas laws). A pressure conversion changes units, not state — keep temperature constant when comparing.

Common Pressure Conversion Mistakes

Mixing gauge and absolute pressure

Comparing a gauge reading to an absolute one without adding the ~1 atm baseline introduces a full atmosphere of error — significant at low pressures.

Treating bar as exactly 1 atm

1 bar is 100 kPa; 1 atm is 101.325 kPa. The 1.3% gap matters in precise engineering and chemistry.

Confusing psi with psia/psig

psia is absolute, psig is gauge. Dropping the suffix loses the ~14.7 psi atmospheric baseline distinction.

Misreading inHg vs mmHg

Inches of mercury (weather/aviation) and millimetres of mercury (medical) differ by a factor of 25.4. Check the length unit.

Why Pressure Conversion Matters

Pressure spans tyres, weather, medicine, diving, vacuum, and heavy industry — and each field settled on its own unit, so gauges, placards, and instruments rarely agree. An under-inflated tyre, a misread blood pressure, or a process line set to the wrong number can have safety and cost consequences, and the gauge-versus-absolute distinction adds a whole atmosphere of potential error.

Because pressure is force over area, it links directly to structural loads, gas behaviour, and fluid flow. A converter that routes through the pascal with exact factors — and surfaces psi, bar, kPa, atm, and mmHg together — lets a mechanic, clinician, diver, or engineer read a single physical pressure in the unit their equipment expects.

Built for mechanics, weather watchers, divers, clinicians, and process engineers converting between psi, bar, kPa, atm, and mmHg.

Linear unit factors follow the BIPM SI brochure, the NIST Guide to the SI, and ISO 80000. Currency rates load live from open.er-api.com; crypto prices from CoinGecko. See our methodology and editorial policy. Educational only — not certified for regulated trading, settlement, medical, or aerospace use.

Pressure Converter FAQs

Divide psi by 14.5038 to get bar, or multiply bar by 14.5038 to get psi. So 32 psi (a typical car tyre) is about 2.21 bar, and 1 bar is 14.5 psi. Both can also be expressed in kPa: 32 psi ≈ 220 kPa.

One standard atmosphere is exactly 101,325 pascals (101.325 kPa), the average air pressure at sea level. One bar is slightly less at 100,000 Pa, so 1 atm is about 1.013 bar — close but not identical.

Gauge pressure is measured relative to the surrounding atmosphere (so a deflated tyre reads 0), while absolute pressure is measured from a perfect vacuum and includes the ~101.325 kPa of atmospheric pressure. Tyre and many industrial gauges read gauge pressure; gas-law and vacuum calculations need absolute.

Multiply mmHg by 0.133322 to get kPa. So a blood pressure of 120 mmHg is about 16 kPa. One mmHg equals one torr (133.322 Pa); medicine keeps using mmHg by long-standing convention.

Almost, but not exactly. One bar is 100,000 Pa and one standard atmosphere is 101,325 Pa, so a bar is about 1.3% less than an atmosphere. For everyday use they're interchangeable, but precise chemistry and engineering keep them distinct.

It uses exact and standard definitions (1 psi = 6,894.757 Pa, 1 bar = 100,000 Pa, 1 atm = 101,325 Pa, 1 mmHg = 133.322 Pa) and routes every conversion through the pascal at full precision, so the result is exact to your input precision.