Compare calculators

Both calculators run independently — change the inputs on either side to compare results.

Manning's Equation Open Channel Calculator

Compute flow velocity and discharge in open channels — rivers, canals, and drains — using Manning's equation. Essential for flood modelling, irrigation design, and stormwater drainage sizing.

Hydraulic Radius (m)

Channel Slope (m/m)

Manning's Roughness (n)

Cross-sectional Area (m²)

Fill in the required fields to see your result.

Fluid Mechanics

Darcy-Weisbach Pressure Drop Calculator

Calculates pressure drop along a pipe section using the Darcy-Weisbach equation. Used by engineers designing water supply, HVAC, and industrial piping systems to size pipes and pumps correctly.

Friction Factor

Pipe Length (m)

Pipe Diameter (m)

Flow Velocity (m/s)

Fluid Density (kg/m³)

Fill in the required fields to see your result.

Key differences

	Manning's Equation Open Channel Calculator	Darcy-Weisbach Pressure Drop Calculator
Category	Fluid Mechanics	Fluid Mechanics
Inputs required	4	5
Result	Flow Rate (m³/s)	Pressure Drop (Pa)
What it does	Compute flow velocity and discharge in open channels — rivers, canals, and drains — using Manning's equation. Essential for flood modelling, irrigation design, and stormwater drainage sizing.	Calculates pressure drop along a pipe section using the Darcy-Weisbach equation. Used by engineers designing water supply, HVAC, and industrial piping systems to size pipes and pumps correctly.