Pressure Conversion Calculator
Convert psi, bar, pascal and more for tyres, tools and tanks
Pressure conversion FAQ
What is pressure in simple terms?
Pressure is just force per unit area. Imagine pushing on a surface: the harder you push and the smaller the area, the higher the pressure. That’s why a thin needle can pierce skin with a small force, while a big blunt object needs a lot more. Most pressure units are just different ways of writing “force divided by area” using different force/area units.
Why so many pressure units — Pa, bar, psi, atm, Torr?
Different fields grew up with different standards:
- Pascals (Pa) and hectopascals (hPa) are SI and common in science and weather.
- Bar and mbar are convenient rounded units near atmospheric pressure.
- psi (pounds per square inch) dominates tyres, tools and many US gauges.
- atm and Torr come from gas and vacuum work.
- kgf/cm² and kgf/m² use kilogram-force per area and show up in older engineering tables.
The calculator stitches all of these together so you don’t have to remember every factor.
What’s the pressure of “1 atmosphere” in other units?
By convention, 1 atmosphere (atm) is defined as about:
- 1 atm ≈ 101,325 Pa.
- 1 atm ≈ 1.01325 bar.
- 1 atm ≈ 14.696 psi.
- 1 atm ≈ 760 Torr.
That’s roughly the average pressure at sea level. The tool uses these same relationships when converting between atm, bar, psi and Torr.
What’s the difference between psi and psf?
psi means pounds per square inch. psf means pounds per square foot. Because a square foot is 144 square inches:
- 1 psi = 144 psf.
- 1 psf ≈ 0.006944 psi.
The calculator includes both units, which is handy if one spec is written in psi and another in psf.
What about gauge vs absolute pressure?
Units like bar, psi and kPa can be measured as gauge (relative to atmospheric) or absolute (relative to vacuum). This calculator just converts the number you give it; it doesn’t know whether it was gauge or absolute. To keep things consistent, only compare like with like: gauge-to-gauge or absolute-to-absolute.
Is this accurate enough for tyres, compressors and scuba?
Yes. Internally everything is converted through Pascals using stable factors and then rounded for display. That’s more than precise enough for tyre pressure, workshop compressors, HVAC specs and scuba planning. For safety-critical work, always double-check against the gauge or documentation that controls the actual system.
From tyre pressure to vacuum level in one clear line
This pressure conversion calculator helps you translate readings across the main systems: bar, psi, Pascal, atmosphere, millibar, kilogram-force per area, pound-force per square foot, and Torr. You enter a value, pick what it’s in (for example psi from your tyre gauge), choose what you want it in (bar, Pa, atm, etc.) and the result card prints a simple line like “32 psi = 2.206 bar”.
1. Pick the units that match your gauge or datasheet
The dropdowns include the units from your reference table:
- Pascals (Pa) for SI calculations and detailed engineering work.
- Hectopascals (hPa) and millibars (mbar) for weather and aviation reports.
- Atmospheres (atm) for gas laws and scuba diving discussions.
- Bar for hydraulics, pumps and many industrial gauges.
- kgf/cm² and kgf/m² for legacy engineering tables using kilogram-force.
- psi (pounds per square inch) and psf (pounds per square foot) for tyres, tools and building loads.
- Torr for vacuum systems and lab work.
You can combine any pair: psi to bar, bar to Pa, atm to psi, mbar to hPa, Torr to Pa, kgf/cm² to bar, or psf to psi.
2. Base-unit method: everything through Pascals
Internally, the calculator uses Pascals (Pa) as the base unit. Each supported unit has a factor that tells the tool how many Pascals it equals. Based on your table:
- 1 Pa = 1 Pa.
- 1 hPa = 100 Pa; 1 mbar = 100 Pa.
- 1 atm ≈ 101,325 Pa.
- 1 bar = 100,000 Pa.
- 1 kgf/cm² ≈ 98,067 Pa.
- 1 kgf/m² ≈ 9.80665 Pa.
- 1 psi ≈ 6,895 Pa (rounded as in your table).
- 1 psf ≈ 47.880208 Pa.
- 1 Torr ≈ 133.322368 Pa.
When you click Convert, the tool multiplies your input by the “to Pa” factor, then divides by the target unit’s factor. That keeps all conversions consistent with the table you provided.
3. Pressure relationships at a glance
This table highlights some of the common pressure relationships the calculator uses so you can sanity-check results or do quick mental estimates.
| Starting Unit | Resulting Unit | Relationship |
|---|---|---|
| Around atmospheric pressure | ||
| atmosphere (atm) | Pa, bar, psi, Torr | 1 atm ≈ 101,325 Pa ≈ 1.01325 bar ≈ 14.696 psi ≈ 760 Torr |
| bar | Pa and psi | 1 bar = 100,000 Pa ≈ 14.504 psi |
| hectopascal (hPa) | Pa and mbar | 1 hPa = 100 Pa = 1 mbar |
| Tyres, tools and loads | ||
| pound per square inch (psi) | Pa and bar | 1 psi ≈ 6,895 Pa ≈ 0.06895 bar |
| pound per square foot (psf) | psi | 1 psf ≈ 0.006944 psi (1 psi = 144 psf) |
| kgf/cm² | bar and psi | 1 kgf/cm² ≈ 0.9807 bar ≈ 14.22 psi |
| Vacuum and lab work | ||
| Torr | Pa and atm | 1 Torr ≈ 133.322 Pa ≈ 0.001316 atm |
| Pascal (Pa) | Torr | 1 Pa ≈ 0.007501 Torr |
4. Reading and using the result
The result card is deliberately simple. If you enter 32 and convert from psi to bar, you’ll see a single line like “32 psi = 2.21 bar” (rounded from the Pa-based calculation). That’s enough to check tyre pressure charts, match a compressor spec, compare an HVAC datasheet, or cross-check a scuba table.
Because every unit flows through Pascals with the same factors used in your detailed table, this calculator behaves like a clean pressure chart that you don’t have to memorize, covering everything from everyday psi gauges to vacuum-level Torr readings.
References and further reading on pressure units
These resources explain how the main pressure units and relationships used here are defined:
- Pascal (unit) — defines the Pascal as the SI unit of pressure (1 Pa = 1 N/m²).
- Bar (unit) — describes the bar, its relation to Pa and atm, and typical usage in engineering.
- Pounds per square inch — covers psi and its use in tyres, hydraulics and many US pressure gauges.
- Torr — explains the Torr, its connection to mmHg and its relation to the atmosphere.
For safety-critical systems (like scuba, boilers or high-pressure hydraulics), always double-check limits and settings against the official documentation and the calibrated gauge you actually use.