# Bar to atm Converter

URL: https://speedycalculator.com/calculators/conversion/bar-to-atm/
Last updated: 2026-10-25

> Convert bar (bar) to standard atmospheres (atm): 1 bar = 0.98692327 atm, so multiply by 0.98692327 or divide by 1.01325. Both fields are editable, so you can also type in standard atmospheres and get bar back.

## Inputs

- Bar (bar)

## Results

- Standard atmospheres

## Formula

```
1 bar = 0.98692327 atm
1 atm = 1.01325 bar
atm = bar × 0.98692327
```

## Explanation

One bar is 100,000 Pa and one atmosphere 101,325 Pa, so 1 bar ≈ 0.9869 atm. Divers and engineers use bar; chemists often use atm.

### How to use the Bar to atm Converter

- Type the number of bar into the **Bar** field. Decimals such as 0.5 are fine.
- Read the answer in **Standard atmospheres** – it updates as you type, with no button to press.
- To convert the other way, type into **Standard atmospheres** and the bar are recalculated.
- Press **Copy results** to copy both values with the page title, or **Copy link** to share this exact conversion.

This page converts only bar ⇄ atm. Need a different unit? Use the general pressure converter, where you can choose any “from” and “to” unit.

### How it works

Both units measure pressure, so they are always in the same ratio: one bar equals 0.98692327 standard atmospheres. The calculator multiplies the number of bar you type by 0.98692327 to give standard atmospheres, and when you type into the standard atmospheres field it divides by the same factor to give bar. Because the ratio never changes, doubling the bar always doubles the standard atmospheres. Results are calculated at full precision and rounded only for display (up to eight decimal places, with very large or small values shown in scientific notation).

### How to convert bar to standard atmospheres

- Write down the value in bar, for example **1 bar**.
- Multiply by the conversion factor 0.98692327 (because 1 bar = 0.98692327 atm).
- 1 × 0.98692327 = **0.98692327 atm**.
- To go back from standard atmospheres to bar, divide by 0.98692327 – or multiply by 1.01325.

### bar to atm conversion table

BarStandard atmospheresStandard atmospheresBar0.5 bar0.49346163 atm1 atm1.01325 bar1 bar0.98692327 atm2 atm2.0265 bar1.01325 bar1 atm5 atm5.06625 bar2 bar1.9738465 atm10 atm10.1325 bar5 bar4.9346163 atm20 atm20.265 bar10 bar9.8692327 atm50 atm50.6625 bar50 bar49.346163 atm100 atm101.325 bar100 bar98.692327 atm1,000 atm1,013.25 bar200 bar197.38465 atm

### What is a bar?

One bar is exactly 100,000 Pa, close to average atmospheric pressure. European tyre pressures, diving, espresso machines and industrial gauges use bar.

### What is a standard atmosphere?

The standard atmosphere is exactly 101,325 Pa, the average air pressure at sea level. Chemistry problems and diving depth calculations often use atm.

### Quick mental conversion

For a fast estimate, multiply bar by about **0.99** to get standard atmospheres; the error is about 0.3%. Use the calculator above when you need the exact figure.

### Common mistakes to avoid

Mixing gauge pressure (psig, barg) with absolute pressure (psia, bara), treating bar and atm as identical, and confusing kgf/cm² with bar.

## Worked example

Inputs — Bar: 1 bar.

Results — **Standard atmospheres = 0.98692327 atm**.

## FAQ

**How many atm is 1 bar?**
About 0.98692 atm.

**How many bar is 1 atm?**
1.01325 bar.

**How do I convert bar to standard atmospheres?**
Multiply the number of bar by 0.98692327. For example, 1 bar × 0.98692327 = 0.98692327 atm.

**How do I convert standard atmospheres back to bar?**
Divide by 0.98692327 (or multiply by 1.01325), or simply type the value into the standard atmospheres field above.

**What is 10 bar in standard atmospheres?**
10 bar = 9.8692327 atm.

**What is 100 bar in standard atmospheres?**
100 bar = 98.692327 atm.

**Is this conversion exact?**
Yes. The factor comes from the official definitions of both units (NIST and the SI), so the only difference you may see is rounding in the last displayed digit.

**Can I convert to other units on this page?**
This page converts only between bar and standard atmospheres. To pick any pressure unit, use the general pressure converter linked under Related calculators.

**What formula does the Bar to atm Converter use?**
1 bar = 0.98692327 atm.


## Sources

- [NIST Special Publication 811 – Guide for the Use of the International System of Units](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44 Appendix C – General tables of units of measurement](https://www.nist.gov/pml/owm/nist-handbook-44-current-edition)