Pressure

Inches of Water to hPa Converter

Convert inches of water (inH₂O) to hectopascals (hPa). 1 inch of water = 2.4908891 hectopascals (exact)

1 inch of water = 2.4908891 hectopascals

How to convert inches of water to hectopascals

FormulahPa = inH₂O × 2.4908891

Multiply the value in inches of water by 2.4908891. To go the other way, multiply by 0.401463076 (or divide by 2.4908891).

An inch of water is larger than a hectopascal: one inch of water contains 2.4908891 hectopascals.

Worked examples

  • 1 inch of water1 inH₂O × 2.4908891 = 2.4908891 hPa
  • 5 inches of water5 inH₂O × 2.4908891 = 12.4544455 hPa
  • 10 inches of water10 inH₂O × 2.4908891 = 24.908891 hPa
  • 20 inches of water20 inH₂O × 2.4908891 = 49.817782 hPa
  • 100 inches of water100 inH₂O × 2.4908891 = 249.08891 hPa

Inches of water to hectopascals conversion table

Values are calculated by the conversion engine and rounded to 8 significant figures.

Inches of water to hectopascals: 0.1–10 inH₂O
Inches of water (inH₂O)Hectopascals (hPa)
0.1 inH₂O0.24908891 hPa
0.25 inH₂O0.62272227 hPa
0.5 inH₂O1.2454445 hPa
1 inH₂O2.4908891 hPa
2 inH₂O4.9817782 hPa
3 inH₂O7.4726673 hPa
4 inH₂O9.9635564 hPa
5 inH₂O12.454445 hPa
6 inH₂O14.945335 hPa
7 inH₂O17.436224 hPa
8 inH₂O19.927113 hPa
9 inH₂O22.418002 hPa
10 inH₂O24.908891 hPa
Inches of water to hectopascals: 12–1,000 inH₂O
Inches of water (inH₂O)Hectopascals (hPa)
12 inH₂O29.890669 hPa
15 inH₂O37.363336 hPa
20 inH₂O49.817782 hPa
25 inH₂O62.272227 hPa
30 inH₂O74.726673 hPa
40 inH₂O99.635564 hPa
50 inH₂O124.54445 hPa
75 inH₂O186.81668 hPa
100 inH₂O249.08891 hPa
250 inH₂O622.72227 hPa
500 inH₂O1,245.4445 hPa
1,000 inH₂O2,490.8891 hPa

About the units

Inch of water (inH₂O)

Conventional value 249.08891 Pa. HVAC duct static pressure and gas-appliance pressures use inches of water column.

Hectopascal (hPa)

One hundred pascals, numerically equal to a millibar. Weather maps show sea-level pressure in hPa (around 1013). One hectopascal equals 100 pascals (Pa).

Frequently asked questions

How many hectopascals are in one inch of water?

There are 2.4908891 hectopascals in one inch of water, and this value is exact by definition.

How do I convert inches of water to hectopascals?

Multiply the number of inches of water by 2.4908891. For example, 10 inH₂O × 2.4908891 = 24.908891 hPa.

How many inches of water are in one hectopascal?

One hectopascal equals 0.401463076 inches of water. That is the reverse factor, 1 ÷ 2.4908891.

What is 10 inches of water in hectopascals?

10 inH₂O = 24.908891 hPa.

Is this inH₂O to hPa converter accurate?

Yes. Both units are defined exactly in terms of SI units, so the conversion factor is exact; results are shown to 12 significant figures by default and you can change precision in the converter. Calculations run in your browser using the same tested engine that generated this page.

Convert inches of water to other units

Convert other units to hectopascals

Try “psi to bar”, “cups”, “binary” or “5 ft in cm”.