Indian plants buy gauges, transmitters and compressors from the USA, Europe and Japan, so psi and bar often meet on the same skid. This guide gives the exact factor, a ready chart, the gauge and absolute trap and a calculator you can trust in the field.
Converting psi to bar is a single multiplication, but mixing gauge and absolute pressure causes real field errors. Here you get the exact factors, a chart from 1 to 10000 psi, solved examples and a calculator for daily instrument work.
What Is PSI to Bar Conversion?
PSI to bar conversion changes a pressure in pounds per square inch into bar by multiplying by 0.0689476, because 1 psi equals 6894.76 Pa and 1 bar is exactly 100,000 Pa. Going the other way, 1 bar equals about 14.5038 psi, so you can also divide the psi value by 14.5038.
- 1 psi = 0.0689476 bar = 6.894757 kPa
- 1 bar = 14.50377 psi = 100 kPa
- 100 psi = 6.8948 bar, 150 psi = 10.342 bar
- Psig converts to bar g; add about 1.013 bar to get bar a
- 1 kg/cm² = 0.980665 bar, so 100 psi = 7.031 kg/cm²
The factors above come from the WIKA data sheet IN 00.08 on commonly used pressure units, linked as a PDF further down. If the idea of reference pressure is new to you, start with our basics of pressure measurement before the examples.
Fluke states that one psi equals 6894.76 pascals and that sea level atmospheric pressure is about 14.69 psia. It also advises that a value marked only as psi should normally be read as a gauge pressure.
PSI to Bar Formula and Bar to PSI Formula
Both directions use the same constant, so learn one and invert it. Keep at least four significant figures for calibration work and two decimals for operator displays.
psi = bar × 14.5038
kPa = psi × 6.894757
MPa = psi × 0.00689476
kg/cm² = psi × 0.070307
The factor follows from 1 lbf = 4.4482 N acting on 1 square inch of 0.00064516 m², which gives 6894.76 Pa. Dividing by 100,000 Pa per bar gives the 0.0689476 used in every conversion of this kind.
The same method links every pressure unit, as our pages on atm to kPa conversion and field instrument unit conversion show. Pressure itself is force over area, which is the idea behind Pascal law in pressure instruments.
A quick mental shortcut is to multiply psi by 0.07, which reads about 1.5 percent high. For 100 psi it gives 7.0 bar against the exact 6.89 bar, fine for a rough check but never for calibration.
PSI to Bar Conversion Chart From 1 to 10000 psi
The chart covers the ranges seen on utility, process and hydraulic gauges. Values are rounded to four decimals for bar and two decimals for kPa.
| psi | bar | kPa | kg/cm² |
|---|---|---|---|
| 1 | 0.0689 | 6.89 | 0.0703 |
| 5 | 0.3447 | 34.47 | 0.3515 |
| 10 | 0.6895 | 68.95 | 0.7031 |
| 14.5 | 0.9997 | 99.97 | 1.0195 |
| 20 | 1.3790 | 137.90 | 1.4061 |
| 30 | 2.0684 | 206.84 | 2.1092 |
| 50 | 3.4474 | 344.74 | 3.5153 |
| 60 | 4.1369 | 413.69 | 4.2184 |
| 80 | 5.5158 | 551.58 | 5.6246 |
| 100 | 6.8948 | 689.48 | 7.0307 |
| 150 | 10.3421 | 1034.21 | 10.5460 |
| 200 | 13.7895 | 1378.95 | 14.0614 |
| 300 | 20.6843 | 2068.43 | 21.0921 |
| 500 | 34.4738 | 3447.38 | 35.1535 |
| 1000 | 68.9476 | 6894.76 | 70.3070 |
| 1500 | 103.4214 | 10342.14 | 105.4604 |
| 3000 | 206.8427 | 20684.27 | 210.9209 |
| 5000 | 344.7379 | 34473.79 | 351.5348 |
| 10000 | 689.4757 | 68947.57 | 703.0696 |
Note that 14.5 psi is almost exactly 1 bar, which is the easiest number to remember on site. Instrument air headers at 100 psi run near 7 bar, while 3000 and 5000 psi are common hydraulic and wellhead ratings.
Before you write any converted range on a datasheet, check the gauge accuracy as well, since a class 1.0 gauge cannot show four decimals; see pressure gauge accuracy classes.
Psig vs Psia vs Bar g vs Bar a
Gauge pressure is measured against the local atmosphere, while absolute pressure is measured against a perfect vacuum. Setra puts average sea level pressure at roughly 14.7 psia, and ambient air always reads 0 psig.
Standard atmosphere = 101.325 kPa = 1.01325 bar = 14.696 psi
psia = psig + 14.696 at sea level
Full vacuum = 0 psia = minus 14.7 psig
The conversion factor is the same for gauge and absolute values, but the reference must stay the same on both sides. So 50 psig becomes 3.447 bar g, while 50 psia becomes 3.447 bar a.
Measured from local atmosphere, so a vented gauge reads zero when open to air.
Measured from a perfect vacuum, so the value never goes below zero.
The difference between two process pressures, with no link to the atmosphere.
Our guide on absolute vs gauge pressure goes deeper into reference types. When you order a transmitter, the code for a gauge pressure transmitter differs from the one for an absolute pressure transmitter, so the unit letters matter.
Write the reference letter on every converted value, such as 6.89 bar g or 7.90 bar a. Many commissioning errors in India start with a datasheet that says only bar.
Solved Examples of PSI to Bar Conversion
Example 1 takes a compressed air receiver set at 150 psig. Multiply by 0.0689476 to get the gauge value in bar.
Absolute at sea level = 10.342 + 1.013 = 11.355 bar a
Example 2 changes a transmitter range of 0 to 500 psig into bar. The span becomes 0 to 34.474 bar g, so a reading of 12 mA, which is 50 percent of span, means 17.237 bar g.
12 mA = 50 % of span
Pressure at 12 mA = 0.5 × 34.474 = 17.237 bar g
The 4 to 20 mA scaling is explained in 4 to 20 mA signal conversion, and it works the same in any unit. Convert the range first, then scale the current.
Example 3 is the reverse case, a European pump rated at 16 bar that must be checked against an American gauge in psi.
Check: 232.06 × 0.0689476 = 16.000 bar
PSI to Bar Calculator With kPa and kg/cm²
Enter a negative psig value for vacuum, down to minus 14.7, and the tool will show the matching bar a; our vacuum pressure calculator covers deeper vacuum work. For high altitude sites, enter the local barometric pressure instead of 1.01325 bar.
Pune sits at roughly 560 m and Shimla at over 2,000 m, so local atmospheric pressure is noticeably below sea level there. Use the real barometric value whenever you convert psig to bar a for gas flow or steam work.
Converting Gauge and Transmitter Ranges
When a gauge has a dual scale, the inner and outer rings use the same pointer, so check that both rings start from zero gauge. Our pressure gauge selection guide explains why the normal reading should sit in the middle third of the dial.
The last step matters most, because a correct number in the wrong unit field is still a trip waiting to happen. Follow our pressure gauge calibration procedure for the bench check.
Related Units: kPa, MPa, kg/cm² and Inches of Water
| Unit | Equal to 1 psi | Common Use in India |
|---|---|---|
| bar | 0.0689476 | Gauges, compressors, boilers |
| kPa | 6.894757 | Low pressure, HVAC, datasheets |
| MPa | 0.00689476 | Hydraulics, pipe ratings |
| kg/cm² | 0.070307 | Older gauges and boiler records |
| inH2O | 27.7076 | Draft and low DP |
| inHg | 2.03602 | Vacuum and barometers |
The inH2O and inHg values come from Setra, and WIKA lists 1 kp/cm² as 0.980665 bar, the technical atmosphere still printed on many old Indian boiler gauges. For water column units, see our guide on the U tube manometer formula.
Fluke points out that a flat tyre reads 0 psig, yet the air inside is still at about 14.7 psia. A gauge only shows how far a pressure sits above the local atmosphere.
Common PSI to Bar Mistakes in the Field
| Mistake | What Happens | Fix |
|---|---|---|
| Gauge and absolute mixed | Error of about 1 bar in the result | Mark g or a on every value |
| kg/cm² used as bar | About 2 percent error | Use the 0.980665 factor |
| Too few decimals | Visible calibration error | Keep four significant figures |
| Wrong unit in the DCS | Operator sees false values | Update unit and range together |
- Close to 1 atmosphere, easy to picture.
- Decimal and linked to SI pascals.
- Matches most European gauges and valves.
- American vendor data uses it.
- Hydraulic ratings are often in psi.
- Easy to confuse gauge and absolute.
WIKA Pressure Unit Conversion Table PDF
Video: How to Convert Pressure Units, psi and bar
PSI to Bar FAQ
Multiply the psi value by 0.0689476 to get bar. For example, 100 psi times 0.0689476 gives 6.8948 bar, which is close to 7 bar.
You can also divide the psi value by 14.5038, and it gives exactly the same answer. Keep the gauge or absolute label the same on both sides of the conversion, so psig always becomes bar g.
One bar is equal to about 14.5038 psi, and WIKA gives 14.50377 psi. So 10 bar is about 145 psi and 16 bar is about 232 psi.
For a rough mental check, use 14.5 psi per bar. It is accurate to better than 0.03 percent, which is fine for almost all gauge readings in the field.
Yes, the psi to bar factor of 0.0689476 is the same for both. Only the zero reference changes between gauge and absolute pressure.
So psig always converts to bar g and psia always converts to bar a. To move from gauge to absolute pressure, add the local atmospheric pressure of about 1.013 bar at sea level.
100 psi equals 6.8948 bar, or 689.48 kPa in SI units. This is close to the normal instrument air header pressure in many Indian process plants.
In kg/cm² the same value is about 7.031, since 1 kg/cm² equals 0.980665 bar. Many older boiler and utility gauges in India still show this unit alongside the bar scale.
14.7 psi is the approximate atmospheric pressure at sea level. Setra gives roughly 14.7 psia, and Fluke quotes a value of 14.69 psia.
It is the offset you add to a psig reading to get psia at sea level. In bar, the same offset is about 1.013 bar, and it falls as the site altitude rises.
Bar is not an SI unit, but it is defined as exactly 100,000 pascals, the SI unit of pressure. That makes it a clean decimal multiple of the pascal.
WIKA notes that Pa and bar are among the admissible units in Germany. In India, bar is the usual unit on gauges, valves and process datasheets.
Related Articles
- Absolute vs Gauge Pressure
- Atm to kPa Pressure Conversion
- Field Instrument Unit Conversion
- How to Calculate Gauge Pressure
- Pressure Gauge Selection Factors
External References
- Conversion Table of Commonly Used Pressure Units, WIKA
- PSI vs PSIG vs PSIA: What Is the Difference, Fluke
- Pound per Square Inch, Wikipedia
What We Learn Today
- The psi to bar factor is 0.0689476, and its inverse is 14.5038, so 100 psi equals 6.8948 bar and 16 bar equals 232.06 psi.
- Gauge and absolute values use the same factor, but you must keep the g or a label and add about 1.013 bar for absolute.
- A transmitter range is converted by multiplying both LRV and URV, then scaling the 4 to 20 mA signal in the new unit.
