Use this sailing calculation for planning or education when the vessel, units, reference directions, environmental conditions, and assumptions are explicitly known.

Wind speed (m/s)

Required number in m/s. True wind speed.

Sail area (m²)

Required number in m². Total sail area.

Drag coefficient

Optional number. Drag coefficient between 0.1 and 2.

The cited overview of Sailing supplies background for the terminology and domain context used by this tool.^[1]

Compute aerodynamic sail force from forceNewtons = 0.5 * 1.225 * windSpeedMs^2 * sailAreaM2 * dragCoefficient. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

Sail force (N)

Returned number in N. Aerodynamic force on the sail.

• Vessel design and loading, sea state, wind, current, tide datum, weather, chart accuracy, equipment, crew, and safety margins can make real conditions differ from a simplified result.
• Wind speed must be at least 0.
• Sail area must be at least 0.
• Drag coefficient must be at least 0.1.
• Drag coefficient must be no greater than 2.
• Use finite inputs in the displayed units, preserve source measurements and assumptions, and independently verify consequential decisions.

Cross-check current charts, tide and weather services, instrument data, vessel manuals, and applicable navigation rules, and retain a conservative alternative plan.

• Wind Pressure on Sail Calculator

  Compute aerodynamic force on a sail from dynamic pressure using 0.5 times air density times wind speed squared times sail area times lift coefficient.

• Sail Load Calculator

  Estimate the aerodynamic load on a sail from wind speed and sail area using a flat-plate drag model.

• Boom Force Calculator

  Compute the compression force on the boom from sheet tension via torque balance about the gooseneck.