Use this engineering calculation for a transparent preliminary estimate or independent arithmetic check when geometry, materials, loads, operating conditions, and units are defined consistently.

Discharge Coefficient

Required number input.

Width Meters (m)

Required number input.

Head Meters (m)

Required number input.

Gravity Meters Per Second Squared (m/s²)

Required number input.

Free-flow sharp-crested rectangular weir discharge with user-supplied coefficient: Q=(2/3)Cd b√(2g)h^(3/2); no end-contraction correction. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Flow Cubic Meters Per Second (m³/s)

The resulting flow cubic meters per second returned as a number.

• Hydraulic equations require consistent datum, fluid properties, geometry, roughness, flow regime, and loss coefficients. Cavitation, air entrainment, unsteady flow, fittings, sediment, free-surface effects, and pump behavior may require a network or numerical model.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check assumptions against drawings, measurements, current material data, and the applicable design code. Apply required load combinations and safety factors, then obtain qualified review and testing for consequential designs.

• Orifice Flow Rate

  Idealized incompressible orifice discharge Q=Cd A√(2Δp/ρ); Cd must be supplied for the actual geometry.

• Convective Heat Transfer

  Newton-law convection heat-transfer rate hAΔT with a supplied convection coefficient at the stated flow condition.

• Critical Depth Rectangular

  Critical depth of rectangular open-channel flow from unit-width discharge q: yc=(q²/g)^(1/3).