Use this calculator for flight-planning study or a first-pass cross-check when all inputs describe the same aircraft, atmospheric condition, and phase of flight.

Current weight (lb)

Actual aircraft weight.

Reference IAS (kt)

IAS from the handbook at the reference weight.

Reference weight (lb)

Reference weight for the published IAS.

Correct an indicated airspeed for weight using the square-root weight ratio. 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]

Corrected IAS (kt)

IAS adjusted for the actual weight.

• Do not use a generic calculator in place of the current aircraft flight manual, approved performance data, operating limitations, NOTAMs, weather, or regulations. Real performance changes with configuration, runway condition, altitude, temperature, wind, loading, and technique.
• 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.

Cross-check the result against the aircraft flight manual or approved planning system, then apply the required safety margins. Keep signed wind, heading, altitude, speed, and fuel conventions explicit.

• Stall Speed Weight Correction Calculator

  Scale a published stall speed for actual weight using the square-root weight ratio.

• Maneuvering Speed Va Calculator

  Scale the maneuvering speed for actual weight using the square-root weight ratio.

• Vr Speed Calculator

  Scale the rotation speed for actual weight using the square-root weight ratio.