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Pressure Unit Converter

Result equals value times the ratio of conversion factors

Pressure Conversion =

1 Pascal (Pa) = 0.00014503768 Pound / Inch² (psi); 1e-5 Bar (bar)

Solution in Other Units

UnitValue
Pascal (Pa)1
Kilopascal (kPa)0.001
Megapascal (MPa)1e-6
Bar (bar)1e-5
Atmosphere (atm)9.8692327e-6
Pound / Inch² (psi)0.00014503768
Inch of Mercury (inHg)0.00029529971
Pound / Foot² (psf)0.020885434
Centimeter of Water (cmH₂O)0.010197162
Dyne / Centimeter² (dyn/cm²)10
Foot of Water (ftH₂O)0.00033455222
Gigapascal (GPa)1e-9
Hectopascal (hPa)0.01
Inch of Water (inH₂O)0.0040146293
Millibar (mbar)0.01
Millimeter of Mercury (mmHg)0.0075006376
Newton / Meter² (N/m²)1
Torr (Torr)0.0075006376

Show Your Work

Result = Value × (Source factor ÷ Target factor)
Base unit for this pressure family is Pascal (Pa).
1 Pascal (Pa) = 1 Pascal (Pa)
1 Pascal (Pa) = 0.00014503768 Pound / Inch² (psi)
1 Pascal (Pa) = 1e-5 Bar (bar)
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How It Works

This converter uses the pascal (Pa) as its base unit, which is one newton of force applied over one square meter of area. Each supported pressure unit has a fixed factor relative to the pascal, so the calculator first converts your input into pascals and then divides by each target-unit factor to populate the full comparison table.

Example Problem

Convert 2 atmospheres (atm) to psi and kPa for a pressure-vessel worksheet.

  1. Start with the source value: 2 atm.
  2. Use the exact definition 1 atm = 101,325 Pa.
  3. Convert to the base unit: 2 × 101,325 = 202,650 Pa.
  4. Convert to psi: 202,650 ÷ 6,894.76 ≈ 29.392 psi.
  5. Convert to kPa: 202,650 ÷ 1,000 = 202.65 kPa.
  6. So 2 atm is 29.392 psi and 202.65 kPa.

Key Concepts

Pressure is force per unit area. The SI base unit is the pascal, but real-world work often uses atmospheres, bar, psi, torr, mmHg, inches of water, and other application-specific units. Because each one is just a different scale built on the same physical quantity, most pressure conversions are direct factor conversions through the pascal.

Applications

  • Meteorology: converting between hPa, millibar, and inches of mercury for weather maps and aviation reports
  • Tire and compressor work: translating psi to bar or kPa when equipment and vehicle specs use different systems
  • Vacuum and laboratory systems: converting torr, mmHg, and pascals for pumps, gauges, and process records
  • Process engineering: checking vessel, piping, and regulator pressures across SI and imperial documentation

Common Mistakes

  • Treating gauge pressure and absolute pressure as the same thing when a calculation actually requires one specific reference state
  • Assuming bar and atmosphere are interchangeable even though 1 atm = 1.01325 bar, which matters in tighter calculations
  • Using rounded factors too early, which can compound when pressure is later used in gas-law or flow-rate calculations

Frequently Asked Questions

How do you convert pressure units?

Convert the source pressure to pascals first, then divide by the target-unit factor. That is the same base-unit method this calculator uses for every supported pressure unit.

What is the formula for converting psi, kPa, bar, and atm?

For most pressure units, the formula is Result = Value × (source factor ÷ target factor), where each factor is defined relative to the pascal.

How many psi are in 1 atmosphere?

One standard atmosphere is about 14.696 psi and exactly 101,325 pascals.

What is the difference between bar and atm?

A bar is exactly 100,000 pascals, while an atmosphere is 101,325 pascals. They are close, but not identical.

Is torr the same as mmHg?

They are extremely close and are often treated as equivalent in practice, but they come from slightly different formal definitions.

Why is pressure sometimes shown in inches of water?

Low-pressure systems such as HVAC ducts and draft measurements are often easier to read in inches of water because the values stay in a practical range.

Can I use this calculator for tire pressure and vacuum pressure?

Yes. The same underlying conversion method works whether you are converting everyday gauge pressures or low-pressure laboratory units.

Pressure Conversion Formula

Pressure conversions use the pascal as the common base unit. The calculator converts your source value into pascals first, then expresses that same pressure in every other supported engineering, scientific, and HVAC unit below.

Result = Value × (Source factor ÷ Target factor)
  • Result — the converted measurement in the target pressure unit
  • Value — the original measurement you enter
  • Source factor — the factor that maps the source unit to the common base unit
  • Target factor — the factor used to express the same base-unit value in the target unit

Worked Examples

Tire Maintenance

How do you convert 32 psi to kPa?

A vehicle door sticker lists tire pressure in psi, but the air compressor reads in kilopascals.

  • Start with the source value: 32 psi.
  • Use the exact relationship 1 psi = 6.89476 kPa.
  • Multiply: 32 × 6.89476 = 220.63232 kPa.
  • You can also divide by 14.5038 to express the same pressure in bar.
  • 220.63232 kPa ≈ 2.2063 bar.
  • The same tire pressure is 220.63 kPa or about 2.21 bar.

A tire pressure of 32 psi is 220.63 kPa.

This is one of the most common real-world pressure conversions drivers need outside the United States.

Diving

What is 2.5 atmospheres in psi?

A pressure reading is given in atmospheres and you want the equivalent in psi for a gauge comparison.

  • Start with the source value: 2.5 atm.
  • Use the definition 1 atm = 14.6959 psi.
  • Multiply: 2.5 × 14.6959 = 36.73975 psi.
  • You can also convert the same value to bar.
  • 2.5 atm ≈ 2.5331 bar.
  • The same pressure is about 36.74 psi.

A pressure of 2.5 atm is about 36.74 psi.

Atmospheres and bar are close, but not identical, so it is worth converting precisely in engineering work.

Vacuum Lab

How do you convert 750 torr to kPa?

A vacuum or process gauge reports torr, but your lab worksheet expects kilopascals.

  • Start with the source value: 750 torr.
  • Use the conversion 1 torr = 0.133322 kPa.
  • Multiply: 750 × 0.133322 = 99.9915 kPa.
  • That is also just under 1 standard atmosphere.
  • 750 torr ≈ 99.9915 kPa.
  • The same reading is essentially 100.0 kPa.

A pressure of 750 torr is about 99.99 kPa.

Torr and mmHg are nearly interchangeable in many lab settings, but the calculator keeps the exact factors straight.

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