processconvert
Pressure

inH₂Otobar

Convert inches of water column (4 °C) (inH₂O) to bar (bar).

Factor1 inH₂O = 0.002490889 bar

Converter

inH₂O

Accepts numbers or expressions, e.g. 150 + 14.7

Result
0.249089bar

Rendered to 6 significant figures.

Formula

Formula
bar = inH₂O × 0.002490889

Multiply any value in inches of water column (4 °C) by 0.002490889 to obtain the value in bar.

Worked example

Convert 100 inH₂O to bar.

  1. 01Start with 100 inH₂O.
  2. 02Multiply by the conversion factor: 100 × 0.002490889 = 0.249089 bar.
Result100 inH₂O = 0.249089 bar

Conversion table

inH₂Obar
10.0024909
20.0049818
50.012454
100.024909
200.049818
500.12454
1000.24909
2000.49818
5001.2454
10002.4909

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from inH₂O to bar?
1 inH₂O equals 0.002490889 bar. To convert, multiply the value in inches of water column (4 °C) by 0.002490889.
How do I convert 1 inH₂O to bar?
1 inH₂O = 0.00249089 bar. For any value, multiply by 0.002490889.
How do I convert bar back to inH₂O?
Divide by the same factor — or equivalently, multiply by 401.4631. So 1 bar = 401.463 inH₂O.
When would I need to convert inch of water column (4 °C) to bar?
Pressure conversions between inH₂O and bar are common when working with mixed-vendor instrumentation, when piping codes use different units to process datasheets, or when converting field readings into SI for hydraulic calculations.
Is the conversion exact?
The factor shown is precise to at least 7 significant figures. For most process-engineering work this is far better than instrument accuracy. For metrology or trade applications, refer to the relevant national standard (NIST, BIPM, ISO 80000).

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