Flow & Velocity Calculator

Calculate flow rate, velocity, or required pipe size.

Flow Formula

V = Q / A

V = velocity (fps), Q = flow (cfs), A = area (sq ft)
GPM × 0.002228 = cfs

Velocity Limits

  • 5 fps: Quiet operation, hot water lines
  • 8 fps: Standard residential/commercial
  • 10 fps: Maximum recommended
  • >10 fps: Water hammer, noise, erosion risk