How many psi is 1 bar?

1 bar is exactly 14.5037738 psi. Both units have exact definitions — a bar is 100 000 Pa and a psi is 6894.757293168 Pa — so the conversion is exact rather than approximate. The commonly quoted 14.7 psi is the standard atmosphere, which is a different reference: 1 atm = 101 325 Pa = 14.6959 psi.

How do I convert kPa to psi?

Divide by 6.894757. So 100 kPa = 14.5038 psi, 250 kPa = 36.2594 psi, and 1000 kPa (1 MPa) = 145.0377 psi. Equivalently, multiply the kPa figure by 0.145038. The matrix above gives the value directly for any pair of units without an intermediate step.

What is the difference between bar and atm?

They are close but not equal: 1 atm = 1.01325 bar exactly, so a bar is about 1.3% smaller than a standard atmosphere. This matters when converting to psi — 1 bar is 14.5038 psi while 1 atm is 14.6959 psi. Gauges are usually calibrated in bar or kPa, while gas-law calculations and standard tables often use atm.

Is kg/cm² the same as bar?

No, though they are close. 1 kgf/cm² = 98 066.5 Pa = 0.980665 bar, so a kgf/cm² is about 2% smaller than a bar. The unit is older and not SI, but it survives on hydraulic and pneumatic gauges and in some Asian and European industrial practice. 1 kgf/cm² = 14.2233 psi.

Why does my gauge reading differ from the calculated pressure?

Check the reference before suspecting the gauge. A gauge reads pressure above atmospheric, so a calculated absolute pressure will be about 1 bar higher. Also check the elevation: atmospheric pressure falls roughly 1 kPa per 90 m of altitude, so a gauge calibrated at sea level reads slightly high at altitude. Finally, check the unit — bar, kgf/cm² and atm are all within 3% of each other and are easy to confuse.

Pressure Conversion Chart

A complete pressure conversion matrix for bar, psi, kPa, MPa, atm and kgf/cm² — read the row unit across to the column unit, with no intermediate step.

Data verified 2026-09-29 · based on NIST SP 811, 2008 edition

Quick Answer

1 bar = 14.5038 psi = 100 kPa. 1 psi = 6.8948 kPa and 1 MPa = 145.038 psi. The matrix below converts any pair among bar, psi, kPa, MPa, atm and kgf/cm² directly — find the row for the unit you have and read across to the unit you want.

Find a unit

Pressure Conversion Matrix — Value of 1 Unit in Each Other Unit

Unit^[2]	bar^[1]	psi^[1]	kPa^[1]	MPa^[1]	atm^[1]	kgf/cm²^[1]	Definition^[2]
bar #	1	14.5038	100	0.1	0.986923	1.01972	Metric pressure; 1 bar = 100 kPa exactly
psi #	0.0689476	1	6.89476	0.00689476	0.068046	0.070307	Pound-force per square inch — the US customary unit
kPa #	0.01	0.145038	1	0.001	0.00986923	0.0101972	Kilopascal — the SI-adjacent metric engineering unit
MPa #	10	145.038	1000	1	9.86923	10.1972	Megapascal — the metric unit for material strength
atm #	1.01325	14.6959	101.325	0.101325	1	1.03323	Standard atmosphere — exactly 101 325 Pa by definition
kgf/cm² #	0.980665	14.2233	98.0665	0.0980665	0.967841	1	Kilogram-force per square centimetre — the older metric unit, still common on gauges
mmHg #	0.00133322	0.0193368	0.133322	0.000133322	0.00131579	0.00135951	Millimetre of mercury at 0 °C — the conventional value, not the true 0 °C value
inHg #	0.0338639	0.491154	3.38639	0.00338639	0.0334211	0.0345316	Inch of mercury at 32 °F — the conventional value used for barometers and altimeters

Each cell is the value of one unit of the row expressed in the column's unit — so the row for bar, read across to psi, gives 14.5038. Every cell is computed from the defining factor of each unit rather than copied from a table, so no pair can disagree with any other pair. mmHg and inHg use the conventional values (0 °C and 32 °F respectively) that gauges and barometers are calibrated against, not the true values at those temperatures — the two differ in the seventh significant figure.

Gauge, Absolute and Differential Pressure

This matrix converts units, not pressure references. Before using it, be sure which reference the number you have is measured against, because the same unit can mean three different pressures.

Absolute pressure is measured from a perfect vacuum and is what the gas laws and thermodynamic tables use. Gauge pressure is measured from ambient atmospheric pressure, and is what almost every pressure gauge in a plant reads. Differential pressure is the difference between two pressures, measured from neither.

The relationship is p_abs = p_gauge + p_atm. At sea level that offset is 1.01325 bar or 14.696 psi — which is why a tyre inflated to 32 psi gauge is at 46.7 psi absolute, and why a vacuum gauge reads −14.7 psi at a perfect vacuum. Converting a gauge reading as though it were absolute introduces an error of about 1 bar, which is enormous at low pressures and negligible above 100 bar.

Gauges are marked accordingly: psig and barg for gauge, psia and bara for absolute. Where no suffix is given, process instrumentation almost always means gauge, and vacuum systems almost always mean absolute.

Why 14.5038 and Not 14.7

Two different numbers appear in pressure work — 14.5038 and 14.6959 — and confusing them is a common error.

1 bar = 14.5038 psi, because a bar is defined as exactly 100 000 Pa and a psi as exactly 6894.757293168 Pa. Both are exact definitions, so this conversion is exact.

1 atm = 14.6959 psi, because a standard atmosphere is defined as exactly 101 325 Pa. Standard atmosphere and bar are not the same thing: 1 atm is about 1.01325 bar. The familiar 14.7 psi figure is the standard atmosphere rounded, and it belongs with atm, not with bar.

The practical consequence: 100 psi is 6.895 bar, while 100 psi is 6.805 atm. If you convert a gauge reading thinking the two references are interchangeable, you introduce a 1.3% error before you have done anything else wrong.

Frequently Asked Questions

How many psi is 1 bar?: 1 bar is exactly 14.5037738 psi. Both units have exact definitions — a bar is 100 000 Pa and a psi is 6894.757293168 Pa — so the conversion is exact rather than approximate. The commonly quoted 14.7 psi is the standard atmosphere, which is a different reference: 1 atm = 101 325 Pa = 14.6959 psi.
How do I convert kPa to psi?: Divide by 6.894757. So 100 kPa = 14.5038 psi, 250 kPa = 36.2594 psi, and 1000 kPa (1 MPa) = 145.0377 psi. Equivalently, multiply the kPa figure by 0.145038. The matrix above gives the value directly for any pair of units without an intermediate step.
What is the difference between bar and atm?: They are close but not equal: 1 atm = 1.01325 bar exactly, so a bar is about 1.3% smaller than a standard atmosphere. This matters when converting to psi — 1 bar is 14.5038 psi while 1 atm is 14.6959 psi. Gauges are usually calibrated in bar or kPa, while gas-law calculations and standard tables often use atm.
Is kg/cm² the same as bar?: No, though they are close. 1 kgf/cm² = 98 066.5 Pa = 0.980665 bar, so a kgf/cm² is about 2% smaller than a bar. The unit is older and not SI, but it survives on hydraulic and pneumatic gauges and in some Asian and European industrial practice. 1 kgf/cm² = 14.2233 psi.
Why does my gauge reading differ from the calculated pressure?: Check the reference before suspecting the gauge. A gauge reads pressure above atmospheric, so a calculated absolute pressure will be about 1 bar higher. Also check the elevation: atmospheric pressure falls roughly 1 kPa per 90 m of altitude, so a gauge calibrated at sea level reads slightly high at altitude. Finally, check the unit — bar, kgf/cm² and atm are all within 3% of each other and are easy to confuse.

Value Sources

Each data column on this page is tied to the source it came from. The numbers in square brackets correspond to the table headers above.

#	Source	Type	Revision / method
[1]	Conversion matrix computed from the defining factor of each unit	derived	Each unit is defined by its value in pascals. The cell at row r, column c is factor(r) ÷ factor(c). Every cell is recomputed at build time, and eight well-known pairs are held as known-value checks — for example 1 bar = 14.5037738 psi and 1 psi = 6.8947573 kPa.
[2]	Pressure unit definitions per ISO 80000-4 and NIST Special Publication 811	standard	NIST SP 811 (2008 edition); ISO 80000-4:2019

Data Sources

Standard	Revision	What it covers on this page
NIST Special Publication 811 — Guide for the Use of the International System of Units	NIST SP 811, 2008 edition	the exact definition of every unit in the matrix
ISO 80000-4 — Quantities and units, Part 4: Mechanics	ISO 80000-4:2019	the pressure unit names and symbols
ISO 2533 — Standard Atmosphere	ISO 2533:1975	the standard atmosphere definition

Cross-checked against:

Every conversion factor taken from its defining SI value rather than from a printed table, so no pair can be inconsistent with any other
Eight widely published conversions held as known-value checks (bar/psi, bar/kPa, psi/kPa, MPa/psi, atm/psi, kgf/cm²/psi)
The whole matrix verified as self-consistent: the diagonal is exactly 1 and every reciprocal pair multiplies to 1

Derived values — the following values on this page are calculated, not taken directly from the standard:

Value	How it is derived
Every conversion value in the matrix	factor(row) ÷ factor(column), using each unit's exact value in pascals. Self-consistency is checked at build time — the diagonal must equal 1 and mirrored cells must be reciprocals.

The matrix converts units only. It does not convert between gauge, absolute and differential pressure — add or subtract atmospheric pressure separately, and be sure which reference the number you have is measured against. mmHg and inHg use the conventional values (0 °C and 32 °F) that instruments are calibrated to.

Accuracy and use. The values on this page are compiled from the published standards and cross-checked sources listed above. Where values are derived, the derivation is stated. No warranty, express or implied, is made as to the accuracy or completeness of this information, and no liability is accepted for any loss or damage arising from its use. Engineering reference data is provided for guidance in preliminary work — before a value is used for design, fabrication or acceptance testing, verify it against the current revision of the governing standard and against your own inspection. The user assumes all risk and responsibility in connection with the use of this information.

Cite This Page

Every value on this page is traceable to the sources listed above. If you use the data in a document, paper or report, cite it as:

Plain text

Engineering Reference. "Pressure Conversion Chart." https://refmanual.com/charts/pressure-conversion/ (accessed 2026-09-29). Data from NIST Special Publication 811 — Guide for the Use of the International System of Units, NIST SP 811, 2008 edition.

BibTeX

@misc{pressure-conversion,
  title        = {Pressure Conversion Chart},
  author       = {{Engineering Reference}},
  howpublished = {\url{https://refmanual.com/charts/pressure-conversion/}},
  note         = {Accessed: 2026-09-29},
  source       = {NIST Special Publication 811 — Guide for the Use of the International System of Units, NIST SP 811, 2008 edition}
}

RIS (EndNote, Zotero, Mendeley)

TY  - ELEC
TI  - Pressure Conversion Chart
AU  - Engineering Reference
PB  - Engineering Reference
UR  - https://refmanual.com/charts/pressure-conversion/
PY  - 2026
DA  - 2026-09-29
N1  - Source: NIST Special Publication 811 — Guide for the Use of the International System of Units, NIST SP 811, 2008 edition
ER  -

Each row in the tables above also has a permanent link — hover a row and use the # link to cite a single value rather than the whole page.