Verification: factors follow standard unit definitions; round for display only.

Bar to psi

Convert bar to psi when European tire placards, scuba tank ratings, or metric equipment datasheets list pressure in bar but your gauge, compressor, or US maintenance log expects pounds per square inch.

The bar and the pound per square inch (psi, or lbf/in²) both measure pressure—force per unit area—but belong to different customary systems. Bar is defined exactly as 100,000 pascals (100 kPa); psi derives from the avoirdupois pound-force over a square inch. Because both trace back to SI through the pascal, the conversion is a simple linear multiplier with no offset.

psi = bar × 14.503773773  ·  equivalently   psi = bar × (100,000 ÷ 6,894.757)

This site's converter uses 1 bar = 100,000 Pa exactly and 1 psi ≈ 6,894.757 Pa (from the defined pound-force and inch dimensions). For display, rounding to 14.5038 per bar is standard. The calculator above applies the full factor; the steps below help you verify manual work or spreadsheet formulas.

Step-by-step conversion (worked example)

Convert 2.5 bar to psi — a common passenger-car tire pressure in metric countries:

1. Write the formula: psi = bar × 14.503773773
2. Multiply: 2.5 × 14.503773773 = 36.2594344325 psi
3. Round for display: 36.3 psi (or 36 psi on a basic gauge)

Always compare against the vehicle's door-jamb placard, not the tire sidewall maximum — the placard lists the manufacturer's recommended cold pressure.

Second worked example (scuba cylinder)

Convert 200 bar — a typical recreational scuba fill pressure:

1. 200 × 14.503773773 = 2,900.7547546 psi
2. Round for display: 2,901 psi

Dive shops in the US often quote cylinder pressure in psi while European ratings and tank stamps use bar. Converting both sides to the same unit prevents over- or under-filling during travel or mixed-equipment dives.

Quick mental estimate (no calculator)

For tire and shop-floor checks, multiply bar by 14.5. Example: 2.2 bar → 2.2 × 14.5 = 31.9 psi (exact: 31.91 psi). The 14.5 shortcut is about 0.03% low compared with the full factor — fine for inflating tires, but use the precise multiplier for hydraulic design, calibration certificates, or safety relief valve settings.

Bar to psi conversion chart

Where bar → psi comes up

• Automotive tires: EU and UK placards, TPMS readouts, and pump displays often show bar; US service bays and analog gauges read psi. A 2.3 bar placard equals roughly 33 psi cold.
• Scuba and breathing air: Cylinder neck stamps and European dive tables use bar; US dive computers and fill logs commonly use psi. A 232 bar rated cylinder holds about 3,365 psi when full.
• Industrial pneumatics & hydraulics: ISO equipment specs and European vendor datasheets list bar; US plant maintenance and OSHA documentation often expect psi. A 250 bar hydraulic test line equals about 3,626 psi.
• Process & instrumentation: Transmitter ranges exported from metric plants must be reconciled before pairing with US-sourced relief valves, regulators, or HMI trend scales.

Psi to bar

Convert psi to bar when US compressor gauges, tire inflators, or hydraulic test reports use psi but you need bar for SI documentation, European supplier quotes, or metric-region equipment ratings.

Reverse the bar-to-psi process by dividing psi by the same factor, or multiplying by the reciprocal 0.068947573. Both routes are equivalent because the relationship is a pure scale factor with no additive offset.

bar = psi ÷ 14.503773773  ·  equivalently   bar = psi × 0.068947573

Step-by-step conversion (worked example)

Convert 32 psi to bar — a typical US tire pressure reading:

1. Divide by 14.503773773: 32 ÷ 14.503773773 = 2.206293 bar
2. Round for display: 2.21 bar

Quick mental estimate (reverse direction)

Approximation: divide psi by 14.5. Example: 100 psi → 100 ÷ 14.5 ≈ 6.9 bar (exact: 6.895 bar). Good for shop-floor sanity checks; use the full factor when the result feeds a P&ID, relief-valve datasheet, or compliance record.

Quick reference (psi → bar)

Reverse conversion is essential when importing US-rated compressors into metric markets, or when reconciling psi-first maintenance logs with bar-based OEM manuals.

Gauge vs absolute, common mistakes, and related tools

The bar–psi factor is exact through SI definitions. Confirm gauge vs absolute notation, avoid rounded shortcuts in safety work, and keep unit symbols explicit in every table.

Bar vs psi at a glance

Gauge pressure vs absolute pressure (brief)

Most tire gauges, shop compressors, and process transmitters in everyday use read gauge pressure — zero on the dial means ambient atmospheric pressure, not a perfect vacuum. Notation: psig or barg. Absolute pressure includes atmospheric head: psia or bara, where sea-level ambient is roughly 14.7 psia ≈ 1.01 bara. Converting bar to psi does not change the reference — a 2.5 barg tire equals about 36.3 psig, not 36.3 psia. Always check whether your source document specifies gauge or absolute before comparing readings across systems or adding atmospheric offset.

Common mistakes to avoid

• Using 14.5 as an exact factor — fine for tire inflation, but ~0.03% off from the defined value. On a 300 bar hydraulic test that is roughly 1 psi of error; use 14.503773773 when safety margins are tight.
• Mixing gauge and absolute readings — comparing 2.5 barg directly to 14.7 psia (1 atm absolute) is meaningless. Convert like-for-like references first.
• Confusing tire sidewall max with placard pressure — the sidewall lists the maximum safe pressure for the tire construction; the door placard lists the recommended operating pressure. Convert the placard value, not the sidewall max.
• Assuming bar and atm are identical — 1 bar = 100 kPa exactly; 1 standard atmosphere = 101.325 kPa. They differ by about 1.3% — significant in calibration and vacuum work.
• Rounding too early in multi-step calculations — carry full precision through intermediate steps (e.g. bar → Pa → psi) and round only the final displayed value.
• Confusing pressure with force — psi and bar are pressure units. Pound-force (lbf) and newtons are force; do not substitute them without knowing the area over which force is applied.

Exactness and round-trip verification

Because 1 bar is defined as exactly 100,000 Pa and 1 psi is tied to defined pound-force and inch dimensions, the conversion is not an empirical approximation. Converting 2.5 bar → 36.259 psi → 2.5 bar should recover the original within floating-point limits. Sanity checks: 1 bar ≈ 14.504 psi, 10 bar ≈ 145.04 psi, 200 bar ≈ 2,901 psi.

Related pressure converters

For the inverse of this page, open psi to bar. Nearby workflows: pascal to psi, pascal to bar, atmosphere to bar, bar to atmosphere, and psi to pascal.