Convert Inches of Water to Kilopascals
Convert Inches of Water (inH₂O) to Kilopascals (kPa) instantly and accurately.
Conversion Formula
kPa = inH₂O × 0.24908891
About Inches of Water
One inch of water column (inH₂O or in WC) = pressure from 1 inch of fresh water at standard gravity ≈ 249.09 Pa. The standard unit for low-pressure measurement in US HVAC and plumbing: ductwork static pressure, fan performance, filter ratings, and gas appliance manifold pressures are all specified in inches WC. Household natural gas supply pressure is typically 7 in WC (0.25 psi). Blower door tests for building air-tightness use 50 Pa ≈ 0.2 in WC test pressure. 1 inH₂O = 249.089 Pa.
About Kilopascals
A kilopascal (kPa) = 1,000 Pa - the practical everyday SI pressure unit for moderate pressures. Car tyre inflation: 200-250 kPa (29-36 psi); truck tyres 550-830 kPa. Blood pressure in SI countries: 16/10.7 kPa (= 120/80 mmHg). Systolic blood pressure 16 kPa. Carbonated beverages are packaged at 200-500 kPa CO₂. Medical oxygen cylinders at 15,000 kPa; scuba cylinders 200-300 bar = 20,000-30,000 kPa. 1 kPa = 1,000 Pa = 0.01 bar = 0.145 psi.
Quick Reference Table
| Inches of Water (inH₂O) | Kilopascals (kPa) |
|---|---|
| 1 inH₂O | 0.249089 kPa |
| 2 inH₂O | 0.498178 kPa |
| 5 inH₂O | 1.24544 kPa |
| 10 inH₂O | 2.49089 kPa |
| 25 inH₂O | 6.22722 kPa |
| 50 inH₂O | 12.4544 kPa |
| 100 inH₂O | 24.9089 kPa |