Millibar to Bar Converter
Common Conversions
| mbar | bar |
|---|---|
| 1 | 0.001 |
| 10 | 0.01 |
| 50 | 0.05 |
| 100 | 0.1 |
| 250 | 0.25 |
| 500 | 0.5 |
| 1000 | 1 |
| 1013.25 | 1.01325 |
| 2000 | 2 |
| 5000 | 5 |
| 10000 | 10 |
| 100000 | 100 |
Why this conversion matters in chemistry
Freeze-dryers and rotary-evaporator controllers read in millibar; thermodynamic data tables anchor on bar. The two are linked by a clean factor of 1000 — exact through the SI definitions of both. A 0.2 mbar primary-drying setpoint translates to 2 × 10⁻⁴ bar on a process-validation report. The conversion is simple decimal arithmetic, but it bridges the instrument readout and the regulatory paperwork that cite the same pressure in different units.
Formula
bar = mbar / 1000
Worked Examples
1000 mbar = 1 bar
The IUPAC standard pressure for tabulated thermodynamic data.
1013.25 mbar = 1.01325 bar
Standard atmospheric pressure — the sea-level baseline calibration in both unit systems.
500 mbar = 0.5 bar
A half-bar reduced pressure for moderate vacuum-distillation work.
100 mbar = 0.1 bar
A typical rotary-evaporator vacuum for solvent removal.
Frequently Asked Questions
How do I convert millibar to bar?
Divide by 1000. The relationship is exact, so 1013.25 mbar becomes precisely 1.01325 bar with no rounding.
Why convert mbar to bar?
Thermodynamic data tables anchor on 1 bar (IUPAC standard pressure), while vacuum gauges read in mbar. The conversion is the routine step that brings an instrument reading into the units the calculation actually wants.
What's the difference between mbar and hPa?
None — 1 mbar equals exactly 1 hPa. Both are 100 Pa. Meteorology has largely shifted to hPa in modern reports; vacuum and chemistry instrumentation stays with mbar.