VMG Explained: Sailing Smarter Upwind and Downwind

If you’ve spent time trimming sails or racing on any point of sail, chances are you’ve heard the term “VMG”—but do you truly understand what it means, how to calculate it, and how to use it to your tactical advantage?

VMG, or Velocity Made Good, is more than just a technical sailing term. It’s one of the most powerful performance indicators for sailors who want to sail faster, smarter, and more efficiently toward a destination—especially when sailing upwind or downwind. Whether you’re racing or passagemaking, mastering VMG helps you translate every knot of boat speed into real progress.

This article will demystify VMG, show you how to calculate it, and reveal how the best sailors use it to make informed decisions on the water.

What Is VMG in Sailing?

VMG stands for Velocity Made Good, which refers to the speed at which your boat is progressing toward a specific point—usually upwind toward the mark, or downwind toward the destination.

It’s important to distinguish between boat speed and VMG. Your boat might be moving at 6 knots through the water, but if you’re sailing at a wide angle from your target, your VMG may only be 3.5 knots—or less. In simple terms, VMG tells you: how fast am I actually getting to where I want to go?

Why VMG Matters for Sailors

VMG is crucial when sailing against or with the wind, because you rarely sail in a straight line. When sailing upwind, boats must tack; when going downwind, they often sail at broad reaches instead of dead downwind for better performance.

That’s where VMG shines: it helps you find the optimal angle of attack, balancing boat speed and heading to achieve the fastest net progress.

In racing, high VMG wins legs. In cruising, it reduces fuel consumption and time at sea. Knowing your VMG helps you make smarter tactical choices—when to tack, when to gybe, and when to bear away or pinch higher.

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How to Calculate VMG

VMG is calculated using the cosine of the angle between your course and the true wind (or target bearing):

VMG = Boat Speed × cos(θ)

where θ is the angle between your actual course and the target bearing.

For example:

If you’re sailing at 6 knots at an angle of 45° from the wind:

cos(45°) ≈ 0.707

VMG = 6 × 0.707 ≈ 4.24 knots

This means your boat is effectively advancing toward the wind at 4.24 knots. As you bear off or sail too close, that number drops.

Modern chartplotters and sailing apps (like SailGrib, Navionics, or Expedition) automatically calculate VMG in real time based on your boat’s instruments, making it easier than ever to use it as a tactical tool.

Upwind VMG: Finding the Sweet Spot

Upwind, your goal is to sail as close to the wind as possible without stalling or losing speed. Sail too high, and you’ll slow down (poor boat speed); sail too low, and you’ll have to tack more often (poor progress).

Using VMG helps you find the sweet spot between pointing angle and speed through the water. This is often referred to as your best upwind angle, and it varies based on sail trim, sea state, and wind strength.

High-performance sailors constantly monitor upwind VMG to:

Identify when a tack becomes more efficient

Determine if they are overpinching or footing too much

Adjust sail shape and trim for best performance

Downwind VMG: Beyond Dead Downwind Sailing

Many cruisers mistakenly assume that sailing straight downwind is fastest—but in most cases, broad reaching at higher speed delivers better VMG than heading directly downwind slowly.

That’s because sails work more efficiently at certain angles, especially when flying a gennaker, spinnaker, or code zero. By increasing boat speed—even if sailing slightly off course—you increase your net speed toward your destination.

Downwind VMG helps you:

Choose the optimal gybe angle for long legs

Time your gybes to maximize speed

Decide when to hoist or drop specialized sails

Tools and Instruments That Display VMG

Most modern sailing electronics include a VMG function, typically accessible on:

Chartplotters (Raymarine, B&G, Garmin)

Sailing apps and routing software (PredictWind, SailGrib WR, iNavX)

NMEA 2000 instrument displays

These systems calculate both:

VMG to wind (useful for racing and tacking decisions)

VMG to waypoint (best for cruising or downwind legs)

Make sure your instruments are calibrated and that wind data is accurate—otherwise your VMG will be unreliable. If sailing shorthanded, consider setting up an autopilot mode that maintains best VMG.

How to Use VMG for Better Tactical Decisions

In racing or performance cruising, VMG informs every maneuver. Smart sailors watch their VMG delta—the difference in VMG before and after a course change.

For example:

If you tack and your VMG increases by 0.5 knots, you’re gaining ground faster.

If it drops, you may need to re-trim or re-evaluate your angle.

On long legs, especially offshore, sailors also use polar diagrams—custom charts that show the optimal VMG angles for each point of sail. These can be integrated into routing tools and autopilots for next-level optimization.

Common Mistakes When Using VMG

Chasing boat speed instead of VMG: Going faster doesn’t always mean you’re going better.

Relying on VMG to wind during a downwind leg: Use VMG to waypoint instead.

Neglecting changing conditions: VMG angles shift with wind strength and sea state.

Ignoring heel angle and comfort: The fastest VMG isn’t always the most sustainable for long-distance cruising.

Use VMG as a compass—not a dictator. It’s one input among many, and its real power lies in helping you make informed, real-time decisions on the water.

Final Thoughts: Sail Smarter, Not Just Faster

Understanding and applying VMG unlocks a deeper layer of sailing strategy. It takes your attention beyond pure speed and connects it to purpose—getting to your destination faster, more efficiently, and with fewer mistakes.

Whether you’re racing around buoys or crossing an ocean, sailing smarter with VMG allows you to harness every puff of wind more effectively. It’s not about brute force—it’s about intelligent sailing.

With the right tools, data, and awareness, VMG becomes more than a number. It becomes a mindset.