Atmospheres to PSI Converter

Atmospheres to PSI

Convert atmospheres (atm) to psi (psi). Both measure force per area, and the conversion comes up in weather, automotive, diving work.

The Formula

`` psi = atmospheres × 14.6959487755 atmospheres = psi × 0.0680459639099 `

One atmosphere is 14.6959 psi, and one psi is 0.068046 atmospheres.

Conversion Table

Atmospheres	PSI
1 atm	14.6959 psi
2 atm	29.3919 psi
5 atm	73.4797 psi
10 atm	146.9595 psi
25 atm	367.3987 psi
50 atm	734.7974 psi
100 atm	1,469.59 psi
500 atm	7,347.97 psi
1,000 atm	14,695.95 psi

The Other Direction

PSI	Atmospheres
1 psi	0.068046 atm
2 psi	0.136092 atm
5 psi	0.34023 atm
10 psi	0.68046 atm
25 psi	1.7011 atm
50 psi	3.4023 atm
100 psi	6.8046 atm
500 psi	34.023 atm
1,000 psi	68.046 atm

What Each Unit Is

Atmospheres (atm) — exactly 101,325 pascals, by definition. The mean air pressure at sea level, adopted as a reference standard.

PSI (psi) — pounds-force per square inch, equal to 6,894.76 pascals. The imperial pressure unit, still standard for US tyres, plumbing and compressed air.

A Sense of Scale

• Pressure doubles at 10 m underwater
• Everest’s summit is about 0.33 atm
• Car tyres run at 32–35 psi
• Household water is 40–60 psi

Doing It in Your Head

Multiply by 44, then divide by 3. That is off by 0.20% — close enough to judge a distance, a weight or a price, and not close enough to sign off on a drawing.

Exact	Mental shortcut
146.9595 psi	146.6667 psi
1,469.59 psi	1,466.67 psi

Precision

The factor 14.6959487755 is rounded. For engineering work carry more digits than the table above, and round only at the end — rounding at each step compounds.

In Code

`javascript const atmosphereToPsi = (value) => value * 14.6959487755; ``

Where This Conversion Comes Up

• Weather
• Automotive
• Diving
• Aviation
• HVAC

How Many Decimals Do You Need?

Rounding the factor costs accuracy, and how much depends on the factor. Converting 137 atm with the factor truncated at each decimal place:

Decimals kept	Factor	137 atm becomes	Error
0	15	2,055	2.0689%
1	14.7	2,013.9	0.0276%
2	14.7	2,013.9	0.0276%
3	14.696	2,013.35	0.0003%
4	14.6959	2,013.34	0.0003%

A rule that holds for any conversion: round once, at the end. Rounding the factor and then multiplying compounds the error through every subsequent calculation, while carrying full precision and rounding the final answer does not.

The right number of significant figures is set by your input, not by the converter. If you measured atmospheres to three significant figures, the answer in psi is only good to three — writing more digits claims precision the measurement never had.