# PSI to Bar Pressure Converter

Convert between PSI, bar, atm, kPa, and mmHg pressure units. Free online pressure converter for engineering, HVAC, automotive, and scientific applications.

## What this calculates

Convert pressure values between PSI, bar, atmospheres, kilopascals, millimeters of mercury, and inches of mercury. This tool uses internationally recognized conversion factors anchored to the exact SI definition of the standard atmosphere.

## Inputs

- **Value** — min 0 — Enter the pressure to convert.
- **From Unit** — options: PSI (lb/in²), Bar, Atmospheres (atm), Kilopascals (kPa), mmHg (Torr), Inches of Mercury (inHg) — Select the source pressure unit.

## Outputs

- **PSI** (psi) — Pounds per square inch.
- **Bar** (bar) — Pressure in bar.
- **Atmospheres** (atm) — Standard atmospheres.
- **Kilopascals** (kPa) — Pressure in kilopascals.
- **mmHg** (mmHg) — Millimeters of mercury (Torr).

## Details

Pressure conversion is essential in engineering, automotive maintenance, HVAC, meteorology, and medical applications. All conversions in this tool are derived from the exact definition: 1 standard atmosphere = 101,325 pascals.

Exact base relationships (from SI definition)

- 1 atm = 101.325 kPa (exact)

- 1 atm = 1.01325 bar (exact)

- 1 atm = 14.695948775 PSI

- 1 atm = 760 mmHg (exact, by definition)

- 1 atm = 29.9213 inHg

Pressure Unit Reference Table

PSI
Bar
atm
kPa
mmHg

1
0.0689
0.0680
6.895
51.71

14.696
1.0133
1.0000
101.33
760.00

30
2.069
2.041
206.84
1,551.06

50
3.448
3.401
344.74
2,585.10

100
6.895
6.803
689.48
5,170.21

Common applications: tire pressure is typically measured in PSI (32-35 PSI for cars), weather barometric pressure uses inHg or hPa (hectopascals = mbar), and blood pressure uses mmHg.

## Frequently Asked Questions

**Q: How many PSI is 1 bar?**

A: 1 bar equals approximately 14.5038 PSI. More precisely, 1 bar = 100 kPa, and since 1 atm = 101.325 kPa = 14.696 PSI, 1 bar = 14.5038 PSI.

**Q: What is normal atmospheric pressure?**

A: Standard atmospheric pressure at sea level is defined as exactly 101.325 kPa, which equals 1 atm, 1.01325 bar, 14.696 PSI, or 760 mmHg. Actual atmospheric pressure varies with weather and altitude.

**Q: What pressure should my car tires be?**

A: Most passenger car tires should be inflated to 30-35 PSI (2.07-2.41 bar) when cold. Check the sticker on your driver's door jamb or owner's manual for the manufacturer's recommended pressure. Do not use the maximum pressure printed on the tire sidewall.

**Q: What is the difference between gauge and absolute pressure?**

A: Gauge pressure (PSIG) is measured relative to atmospheric pressure. A tire at 32 PSIG has 32 PSI above atmospheric. Absolute pressure (PSIA) includes atmospheric pressure, so that tire is at about 46.7 PSIA (32 + 14.696). This converter works with absolute values.

---

Source: https://vastcalc.com/calculators/conversion/psi-to-bar
Category: Conversion
Last updated: 2026-04-21