Convert pipe diameter measurements between inches, feet, millimeters, centimeters, meters, radius, circumference, and pipe cross-sectional area.
Inches to millimeters:
1 in = 25.4 mm
Millimeters to inches:
1 mm = 0.0393701 in
Diameter to radius:
radius = diameter ÷ 2
Diameter to circumference:
circumference = π × diameter
Pipe diameter conversions are useful for plumbing, irrigation, drainage, water lines, pipe fittings, sleeve sizing, hole sizing, pipe flow estimates, and construction layout.
Use this converter when switching between diameter, radius, circumference, cross-sectional area, imperial units, and metric units.
Your result shows the entered pipe measurement converted from the starting unit into the selected ending unit. The converter also shows the equivalent pipe diameter so you can compare diameter, radius, circumference, and area.
For actual pipe selection, remember that nominal pipe size may not equal the measured outside or inside diameter. Use a pipe size chart or manufacturer data when matching pipe and fittings.
Multiply inches by 25.4. For example, 2 inches equals 50.8 millimeters.
Divide circumference by pi. For example, a circumference of 6.283 inches equals a 2 inch diameter.
Multiply radius by 2. For example, a 1 inch radius equals a 2 inch diameter.
No. Nominal pipe size is a trade size. The actual outside diameter or inside diameter can be different.
No. A pipe diameter converter changes measured diameter-related units. A pipe size converter compares nominal pipe sizes with common actual pipe dimensions.