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.

Published minimum sink (kt)

Speed for minimum sink at the reference weight.

Published weight (lb)

Weight at which the speed was published.

Compute the speed for minimum sink rate scaled by the fourth-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]

Minimum sink speed (kt)

Speed for minimum sink at the current 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.

• Max Range Airspeed Calculator

  Estimate the best glide airspeed for maximum range as the square root of three times the minimum-sink speed.

• 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.