Velocity Made Good (VMG) Calculator

The Velocity Made Good (VMG) calculator determines your actual speed of progress directly towards or away from the wind. It is an essential metric for sailors and racers who need to optimize their heading to reach a mark as fast as possible, balancing boat speed with the optimal sailing angle.

Nautical (Knots) Standard (MPH)

Understanding Velocity Made Good (VMG)

Sailboats cannot sail directly into the wind, so they must zig-zag (tack) at an angle to reach an upwind destination. VMG measures how much of your total boat speed is actually moving you closer to your upwind (or downwind) mark.

Why VMG Matters

A boat might sail extremely fast at a 90-degree angle to the wind, but its VMG to an upwind mark would be zero—it's moving fast, but making no progress toward the destination. Conversely, pinching too close to the wind might point the boat right at the mark, but the boat's speed will drop drastically. VMG helps you find the "sweet spot" where the combination of your angle and speed gets you to the mark fastest.

The Math Behind It

  • Formula: VMG = Boat Speed × cos(True Wind Angle)
  • Upwind VMG (0° to 89°): Results in a positive value. You are making progress toward the wind.
  • Crosswind (90°): VMG is exactly zero. You are making no progress upwind or downwind.
  • Downwind VMG (91° to 180°): Mathematically results in a negative value (often called VMC or downwind VMG), meaning you are making progress away from the wind source.
Source: onlysuperyachts.com/calculators/velocity-made-good-vmg-calculator/