---
title: "Millibars to Standard atmospheres — mbar to atm converter"
description: "1 millibar = 0.0009869 standard atmospheres. Conversion table, the exact formula, and a calculator for any value."
url: https://atoneplace.net/convert/millibars-to-atmospheres/
site: "At One Place"
---

# Millibars to standard atmospheres

**1 millibar in standard atmospheres: 1 mbar = 0.0009869 atm**

atm = mbar × 0.000986923267

To convert millibars to standard atmospheres, multiply by 0.000986923267. The table below gives the values people look up most often, and the converter works for any number.

## Millibars to standard atmospheres table

*Common millibar values converted to standard atmospheres.*

| Millibars | Standard atmospheres |
| --- | --- |
| 1 mbar | 0.0009869 |
| 2 mbar | 0.0019738 |
| 3 mbar | 0.0029608 |
| 4 mbar | 0.0039477 |
| 5 mbar | 0.0049346 |
| 10 mbar | 0.0098692 |
| 15 mbar | 0.014804 |
| 20 mbar | 0.019738 |
| 25 mbar | 0.024673 |
| 30 mbar | 0.029608 |
| 40 mbar | 0.039477 |
| 50 mbar | 0.049346 |
| 75 mbar | 0.074019 |
| 100 mbar | 0.098692 |
| 250 mbar | 0.24673 |
| 500 mbar | 0.49346 |
| 1,000 mbar | 0.98692 |

## How the conversion works

The relationship is atm = mbar × 0.000986923267. Both units measure pressure, so the conversion is a fixed factor that never changes.

## Common questions

### How many standard atmospheres are in one millibar?

One millibar equals 0.0009869 standard atmospheres. atm = mbar × 0.000986923267.

### How do you convert millibars to standard atmospheres?

Use atm = mbar × 0.000986923267. So 10 mbar is 0.0098692 atm.

### How many millibars are in one standard atmosphere?

One standard atmosphere equals 1,013.25 millibars, which is the reverse of the conversion above.

## Related pages

- [Standard atmospheres to Millibars](https://atoneplace.net/convert/atmospheres-to-millibars/)
- [Millibars to Pascals](https://atoneplace.net/convert/millibars-to-pascals/)
- [Millibars to Kilopascals](https://atoneplace.net/convert/millibars-to-kilopascals/)
- [Millibars to Bars](https://atoneplace.net/convert/millibars-to-bar/)
- [Millibars to Pounds per square inch](https://atoneplace.net/convert/millibars-to-psi/)
- [Millibars to Torrs](https://atoneplace.net/convert/millibars-to-torr/)

## Sources

- Guide for the Use of the International System of Units (SP 811) — NIST (https://www.nist.gov/pml/special-publication-811) [Public domain (US Government)]
- The International System of Units (SI Brochure) — Bureau International des Poids et Mesures (https://www.bipm.org/en/publications/si-brochure)
- Calculated on this page — At One Place (/about/)