What is the lift coefficient (CL)?

The lift coefficient is a dimensionless number that describes how much lift a wing generates relative to the dynamic pressure and reference area. A higher CL means more lift per unit of dynamic pressure. Typical values range from about 0.2 at cruise to 2.5 or more at maximum flap extension.

What is the lift equation used here?

The calculator uses the standard aerodynamic lift equation: L = 0.5 * rho * v^2 * S * CL. Rearranged to solve for CL: CL = (2 * L) / (rho * v^2 * S), where L is lift force (N), rho is air density (kg/m^3), v is velocity (m/s), and S is wing reference area (m^2).

What air density should I use?

Standard sea-level air density is 1.225 kg/m^3 at 15 degrees C (ISA conditions). At higher altitudes or temperatures, density decreases. For example, at 3000 m altitude, rho is approximately 0.909 kg/m^3. Use a standard atmosphere table or a density altitude calculator for precise values.

What counts as the reference wing area?

The reference area (S) is the wing planform area — the projected surface area of the wing as viewed from directly above, including the portion passing through the fuselage. It is the conventional reference area used in the lift, drag, and moment coefficient definitions.

Can I use different units?

This calculator uses SI units: Newtons for force, kg/m^3 for density, m/s for velocity, and m^2 for area. To convert from imperial units, use: 1 lbf = 4.44822 N, 1 slug/ft^3 = 515.379 kg/m^3, 1 ft/s = 0.3048 m/s, 1 ft^2 = 0.0929 m^2.

Lift Coefficient Calculator

Enter lift force, air density, velocity, and wing area to instantly compute the dimensionless lift coefficient (CL).

Flight Conditions

All inputs use SI units (N, kg/m³, m/s, m²).

Lift Force, L (N)

Total aerodynamic lift force acting on the wing.

Air Density, ρ (kg/m³)

Standard sea-level = 1.225 kg/m³.

Velocity, v (m/s)

Freestream airspeed (true airspeed at the wing).

Reference Wing Area, S (m²)

Planform (top-view projected) area of the wing.

Lift Coefficient

—

C_L (dimensionless)

Enter values on the left and click Calculate.

Formula Used

C_L = 2L ÷ (ρ × v² × S)

where L = lift (N), ρ = air density (kg/m³), v = velocity (m/s), S = wing area (m²)

Typical Lift Coefficient Reference Values

0.2 – 0.5

Cruise (clean wing)

0.8 – 1.2

Approach / descent

1.5 – 2.5

Takeoff / flaps down

2.5 – 3.5

Max (slats + flaps)

Summary

Enter lift force, air density, velocity, and wing area to instantly compute the dimensionless lift coefficient (CL).

How it works

Enter the total lift force acting on the wing in Newtons (N).
Enter the air density in kg/m^3 (standard sea-level air is 1.225 kg/m^3).
Enter the freestream velocity (airspeed) in meters per second.
Enter the reference wing area (planform area) in square meters.
Click Calculate to compute the lift coefficient (CL).
Use the Reset button to clear all fields and start a new calculation.

Use cases

Verifying lift coefficient values for aircraft wings during conceptual design.
Checking CL against published polar data for a known airfoil.
Comparing required CL across flight conditions against known airfoil polar limits.
Teaching aerodynamics fundamentals and the lift equation.
Estimating CL for drone and UAV wing sizing.
Validating wind-tunnel test results against theoretical predictions.
Supporting aerospace engineering coursework and homework problems.
Analyzing glider or sailplane performance at various speeds.

Frequently Asked Questions

Last updated: 2026-09-22 · Reviewed by Nham Vu