Pipe Size Calculator
Determine the correct pipe size for your plumbing project based on flow requirements and application.
Calculator
Calculation Method
Fixture Count
Pipe Material
How it Works
This pipe size calculator helps you determine the right diameter pipe for your plumbing or drainage project based on water flow rate, type of pipe, and other factors.
How It Calculates
The calculator uses these key considerations to recommend the appropriate pipe size:
- Flow rate (gallons per minute)
- Velocity limits (to prevent excessive noise and erosion)
- Friction loss (based on pipe material and length)
- Pressure requirements at fixtures
Common Pipe Sizes and Applications
Here's a quick reference guide for common residential pipe sizes:
- 1/2" pipe: Individual fixture supply lines (faucets, toilets)
- 3/4" pipe: Branch lines, small water heaters, and appliances
- 1" pipe: Main trunk lines, large appliances, multiple bathroom groups
- 1-1/4" to 2" pipe: Home main water lines, multiple bathrooms
- 3" and larger: Commercial applications, main drain lines
Pipe Materials
Different pipe materials have different flow characteristics:
- Copper: Smooth interior, excellent flow characteristics
- PEX: Flexible, smooth interior, good flow characteristics
- PVC: Smooth interior, excellent for drain lines
- Galvanized: Rough interior that can become restrictive over time
- Cast Iron: Used for drain lines, can be restrictive