Pipe Fitting Loss Coefficient (K-factor) Calculator

Calculation Method:

Crane TP-410 Hooper 2-K Darby 3-K

K = (L/D) × f_T

Standard method. Best for turbulent flow (Re > 10,000) and quick estimates.

Select Fitting

Nominal Pipe Size

ID = 4.026", f_T = 0.0160

Pipe Length

For straight pipe pressure drop calculation

Flow Velocity

ft/s

Fluid Density

lb/ft³

Viscosity (optional)

lb/(ft·s)

Default: water @ 60°F

Fluid Type

Current Properties:
Density: 62.4 lb/ft³
Viscosity: 0.000672 lb/(ft·s)

Understand K-factor methods, Reynolds effects, and friction loss fundamentals

Pressure drop: ΔP = K × ρV² / (2g × 144) [psi]

Crane TP-410: Industry standard. Fast and conservative. Use for Re > 10,000 and typical process conditions. May underpredict at low Re.
Hooper 2-K: Adds Reynolds correction. Better for laminar and transitional flow. Good balance of accuracy and simplicity.
Darby 3-K: Most accurate across all conditions. Accounts for Re and size scaling. Use for critical calculations and unusual conditions.

For Re > 10,000 in 1"–10" pipe, all three methods typically agree within 15%.

Results