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Pressure

inH₂OtoN/mm²

Convert inches of water column (4 °C) (inH₂O) to newtons per square millimetre (N/mm²).

Factor1 inH₂O = 0.0002490889 N/mm²

Converter

inH₂O

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

Result
0.249089N/mm²

Rendered to 6 significant figures.

Formula

Formula
N/mm² = inH₂O × 0.0002490889

Multiply any value in inches of water column (4 °C) by 0.0002490889 to obtain the value in newtons per square millimetre.

Worked example

Convert 1000 inH₂O to N/mm².

  1. 01Start with 1000 inH₂O.
  2. 02Multiply by the conversion factor: 1000 × 0.0002490889 = 0.249089 N/mm².
Result1000 inH₂O = 0.249089 N/mm²

Conversion table

inH₂ON/mm²
10.00024909
20.00049818
50.0012454
100.0024909
200.0049818
500.012454
1000.024909
2000.049818
5000.12454
10000.24909

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from inH₂O to N/mm²?
1 inH₂O equals 0.0002490889 N/mm². To convert, multiply the value in inches of water column (4 °C) by 0.0002490889.
How do I convert 1 inH₂O to N/mm²?
1 inH₂O = 0.000249089 N/mm². For any value, multiply by 0.0002490889.
How do I convert N/mm² back to inH₂O?
Divide by the same factor — or equivalently, multiply by 4014.631. So 1 N/mm² = 4014.63 inH₂O.
When would I need to convert inch of water column (4 °C) to newton per square millimetre?
Pressure conversions between inH₂O and N/mm² 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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