Calculate the lift coefficient (CL) for any wing or aerodynamic surface. Enter the lift force, flow velocity, reference area, and fluid density — and get the dimensionless lift coefficient used in aircraft design, hydrofoil analysis, and aerodynamic research.
Lift Coefficient (C_L)
--
Dynamic Pressure (q)
--
Fluid Density Used (ρ)
--
Lift per Unit Area
--
The lift coefficient (C_L) is a dimensionless number that quantifies how effectively a surface — such as a wing or hydrofoil — generates lift relative to the dynamic pressure and area it presents to the fluid. A higher C_L means the surface is generating more lift for a given speed and area. It is widely used in aircraft design, wind engineering, and hydrodynamics.
The lift coefficient is calculated using: C_L = 2L / (ρ × V² × A), where L is the lift force in Newtons, ρ is fluid density in kg/m³, V is flow velocity in m/s, and A is the reference (wing) area in m². This rearranges the fundamental lift equation L = ½ × ρ × V² × A × C_L.
Measure or estimate the lift force acting on your surface, then divide it by the product of dynamic pressure (½ × ρ × V²) and the reference area. For example, a wing generating 15,000 N of lift at 100 m/s in sea-level air (1.225 kg/m³) with a 20 m² area has a C_L of 2 × 15000 / (1.225 × 100² × 20) ≈ 0.1224.
Dynamic pressure (q) is the kinetic energy per unit volume of a moving fluid, calculated as q = ½ × ρ × V². It represents the pressure a surface experiences due to the fluid's motion. The lift coefficient normalizes lift force by dynamic pressure and area, making it a property of the shape — not the speed or density.
C_L is influenced by the shape and camber of the airfoil, the angle of attack (angle between the chord line and the oncoming flow), the Reynolds number (a measure of flow regime), surface roughness, and the presence of high-lift devices like flaps or slats. It is not directly affected by speed or fluid density — those are accounted for in the dynamic pressure term.
For a typical commercial aircraft wing in cruise, C_L is roughly 0.3–0.6. At low speeds during takeoff and landing with flaps deployed, C_L can reach 2.0–3.5. High-performance gliders and sailplanes are designed to operate at high C_L values to maximize efficiency at low speeds.
Yes. The lift coefficient formula applies equally to any fluid — air, water, or other liquids. Simply select the appropriate fluid density from the preset options (e.g. Fresh Water at 998.2 kg/m³ or Sea Water at 1025 kg/m³), or enter a custom density. The C_L result is the same dimensionless quantity used for hydrofoils and underwater surfaces.
Both are dimensionless aerodynamic coefficients that normalize force by dynamic pressure and area, but they measure different forces. The lift coefficient (C_L) describes force perpendicular to the flow direction, while the drag coefficient (C_D) describes force parallel to (opposing) the flow. The lift-to-drag ratio (L/D = C_L / C_D) is a key measure of aerodynamic efficiency.