Metric and imperial conversion table provides a quick reference for comparing common metric and imperial units used in valve, flange, pipe, and industrial engineering specifications. It covers size, length, mass, temperature, area, volume, pressure, flow, power, energy, and torque conversions to help engineers and buyers check technical data more easily.
Nominal Size Conversion Table
| Inch | DN | Inch | DN | Inch | DN |
|---|---|---|---|---|---|
| 1/8 | 4 | 5 | 125 | 32 | 800 |
| 1/4 | 6 | 6 | 150 | 34 | 850 |
| 3/8 | 10 | 8 | 200 | 36 | 900 |
| 1/2 | 15 | 10 | 250 | 42 | 1050 |
| 3/4 | 20 | 12 | 300 | 48 | 1200 |
| 1 | 25 | 14 | 350 | 54 | 1350 |
| 1 1/4 | 32 | 16 | 400 | 60 | 1500 |
| 1 1/2 | 40 | 18 | 450 | 64 | 1600 |
| 2 | 50 | 20 | 500 | 72 | 1800 |
| 2 1/2 | 65 | 24 | 600 | 80 | 2000 |
| 3 | 80 | 26 | 650 | 84 | 2100 |
| 3 1/2 | 90 | 28 | 700 | 88 | 2200 |
| 4 | 100 | 30 | 750 | 96 | 2400 |
Length, Mass, Temperature, Area and Volume Conversion Table
| Category | Symbol | Multiply | By | To Obtain | Symbol |
|---|---|---|---|---|---|
| Length | In. | Inches | 2.54 | Centimeters | cm |
| Ft. | Feet | 30.48 | Centimeters | cm | |
| mm | Millimeters | 0.03937 | Inches | In. | |
| cm | Centimeters | 0.3937 | Inches | In. | |
| m | Meters | 3.2808 | Feet | Ft. | |
| Mass | Oz. | Ounces | 28.35 | Grams | g |
| Lb. | Pounds | 0.4536 | Kilograms | kg | |
| g | Grams | 0.03527 | Ounces | Oz. | |
| kg | Kilograms | 2.205 | Pounds | Lb. | |
| Temperature | °F | Fahrenheit | (°F – 32) × 5 ÷ 9 | Celsius | °C |
| °C | Celsius | °C × 9 ÷ 5 + 32 | Fahrenheit | °F | |
| Area | In.2 | Square Inches | 6.45 | Square Centimeters | cm2 |
| Ft.2 | Square Feet | 0.0929 | Square Meters | m2 | |
| cm2 | Square Centimeters | 0.155 | Square Inches | In.2 | |
| Volume | Fl. Oz. | Fluid Ounces | 29.5625 | Milliliters | ml |
| Qt. | Quart | 0.946 | Liters | L | |
| Gal. | Gallons | 3.785 | Liters | L | |
| Ft.3 | Cubic Feet | 0.0283 | Cubic Meters | m3 | |
| ml | Milliliters | 0.0338 | Fluid Ounces | Fl. Oz. | |
| L | Liters | 1.0571 | Quart | Qts. | |
| L | Liters | 0.2642 | Gallons | Gal. | |
| m3 | Cubic Meters | 35.34 | Cubic Feet | Ft.3 | |
| In.3 | Cubic Inches | 5.787 × 10-4 | Cubic Feet | Ft.3 | |
| Ft.3 | Cubic Feet | 1728 | Cubic Inches | In.3 |
Pressure Conversion Table
| Category | Symbol | Multiply | By | To Obtain | Symbol |
|---|---|---|---|---|---|
| Pressure | PSI | Pounds per Square Inch | 0.069 | Bar | No symbol |
| PSI | Pounds per Square Inch | 6.89 | Kilopascals | kPa | |
| PSI | Pounds per Square Inch | 0.07 | Kilogram per Square Centimeter | kg/cm2 | |
| Lb./Ft.2 | Pounds per Square Foot | 4.88 | Kilogram per Square Meter | kg/m2 | |
| kPa | Kilopascals | 0.145 | Pounds per Square Inch | PSI | |
| kg/cm2 | Kilogram per Square Centimeter | 14.22 | Pounds per Square Inch | PSI | |
| No symbol | Bar | 14.5 | Pounds per Square Inch | PSI | |
| Atmospheres | 29.92 | Inches of Mercury at 0°C | |||
| Atmospheres | 14.7 | Pounds per Square Inch | |||
| Feet of Water | 0.4335 | Pounds per Square Inch | |||
| Inches of Mercury | 0.4912 | Pounds per Square Inch | |||
| Pounds per Square Inch | 2.307 | Feet of Water | |||
| Pounds per Square Inch | 2.036 | Inches of Mercury |
Pressure Class and Nominal Pressure Comparison Table
| ASME Class | 150 | 300 | 400 | 600 | 800 | 900 | 1500 | 2500 |
|---|---|---|---|---|---|---|---|---|
| Nominal Pressure MPa | 0.6 MPa 1.0 MPa 1.6 MPa 2.0 MPa | 2.5 MPa 4.0 MPa 5.0 MPa | 6.4 MPa | 10.0 MPa | – | 15.0 MPa | 25.0 MPa | 42.0 MPa |
| PN Rating | PN6 PN10 PN16 PN20 | PN25 PN40 PN50 | PN64 | PN100 | – | PN150 | PN250 | PN420 |
Valve Nominal Pressure Series MPa (bar)
| 0.5 (5.0) | 0.1 (1.0) | 0.25 (2.5) | 0.4 (4.0) | 0.6 (6.0) | 0.8 (8.0) |
| 1.0 (10.0) | 1.6 (16.0) | 2.0 (20.0) | 2.5 (25.0) | 4.0 (40.0) | 5.0 (50.0) |
| 6.3 (63.0) | 10.0 (100.0) | 15.0 (150.0) | 16.0 (160.0) | 20.0 (200.0) | 25.0 (250.0) |
| 28.0 (280.0) | 32.0 (320.0) | 42.0 (420.0) | 50.0 (500.0) | 63.0 (630.0) | 80.0 (800.0) |
| 100.0 (1000.0) | 125.0 (1250.0) | 160.0 (1600.0) | 200.0 (2000.0) | 250.0 (2500.0) | 335.0 (3350.0) |
Flow, Power, Energy and Torque Conversion Table
| Category | Symbol | Multiply | By | To Obtain | Symbol |
|---|---|---|---|---|---|
| Flow | — | Cubic Feet / Min. | 62.43 | Pounds of Water / Min. | — |
| — | Cubic Feet / Sec. | 448.831 | Gallons / Min. | — | |
| — | m3 / hr | 4.403 | US GPM | — | |
| Power | — | Horsepower | 33,000 | Ft.-Lb. / Min. | — |
| — | Horsepower | 550 | Ft.-Lb. / Sec. | — | |
| — | Horsepower | 745.7 | Watts | W | |
| — | Ft.-Lb. / Sec. | 4.6263 | BTU / Hr | — | |
| kW | Kilowatts | 1.341 | Horsepower | HP | |
| Energy | BTU | British Thermal Unit | 778.3 | Ft.-Lbs. | — |
| kWh | Kilowatt-Hrs | 3413 | BTU | BTU | |
| Torque | kgf·m | Kilogram-force Meter | 10.2 | Nm | Nm |
| Nm | Newton Meter | 8.8585 | lbf·in | lbf·in |
Note: These conversion values are for general engineering reference only. Final valve, flange, and pipeline specifications should be confirmed according to the applicable project standard.