Velocity made good, upwind, downwind or to a waypoint
The example is the Offshore Racing Congress’s sample speed guide for a Tripp 40 in 6 knots of true wind: 6.07 knots at 52° to the wind, or 5.39 knots at 42°, its best angle upwind. The calculator leaves out current and leeway.
Velocity made good (VMG) is the part of your boat speed that takes you straight toward the wind or straight away from it: boat speed × cos(true wind angle). A sailboat making 6.07 knots at 52° to the true wind makes good 6.07 × cos 52° = 3.74 knots upwind. Toward a waypoint, the same calculation with the angle between your course and the bearing to the waypoint gives the velocity made good to it, which the Offshore Racing Congress (ORC) calls VMC. The calculator above does both, and compares a second angle so you can see whether pointing higher or sailing faster and lower gets you there sooner.
VMG = boat speed × cos(true wind angle) · VMC to a waypoint = boat speed × cos(course − bearing to the waypoint) · Speed across = boat speed × sin(angle) · Time to the mark = distance ÷ VMG. A true wind angle under 90° gives VMG upwind, over 90° downwind; at 90° the boat makes no progress either way.
How to Calculate VMG: the Vector Method
Speed and direction together make a vector, and navigators solve problems of speed and direction with vector diagrams: The American Practical Navigator (Bowditch) finds a ship’s track and speed made good through a current that way. VMG splits the boat’s velocity into two parts, one along the direction that matters, the true wind or the bearing to a mark, and one across it. The part along it is the speed times the cosine of the angle between them, and the part across it the speed times the sine. In the example, 6.07 knots at 52° gives 3.74 knots toward the wind and 4.78 knots across it. Downwind the angle is over 90° and the cosine negative: the boat makes good its VMG away from the wind, which is what you want on a run to a leeward mark.
The share of your speed that becomes VMG at each true wind angle:
| True wind angle | VMG, share of boat speed | Direction |
|---|---|---|
| 30° | 87% | upwind |
| 35° | 82% | upwind |
| 40° | 77% | upwind |
| 45° | 71% | upwind |
| 50° | 64% | upwind |
| 60° | 50% | upwind |
| 90° | 0% | none |
| 120° | 50% | downwind |
| 135° | 71% | downwind |
| 150° | 87% | downwind |
| 165° | 97% | downwind |
| 180° | 100% | downwind |
VMG in the ORC Speed Guide
The Offshore Racing Congress rates racing yachts with a velocity prediction program that works out a boat’s speed at true wind angles from 52° to 180° and, for each wind speed, the two angles at which VMG is greatest: the best angle for beating to windward and the best for running. Its sample speed guide for a Tripp 40, Paragon of Virtue, lists the boat speed and VMG at each angle. In 6 knots of true wind, VMG from the calculator, worked out from the rounded boat speeds in the guide, matches the ORC’s figures to within 0.01 knot:
| True wind angle | Boat speed, kn | ORC VMG, kn | Calculator VMG, kn |
|---|---|---|---|
| 42.0° | 5.39 | 4.01 | 4.01 |
| 52° | 6.07 | 3.74 | 3.74 |
| 60° | 6.42 | 3.21 | 3.21 |
| 75° | 6.77 | 1.75 | 1.75 |
| 90° | 6.80 | 0.00 | 0.00 |
| 110° | 6.14 | 2.10 | 2.10 |
| 135° | 5.26 | 3.72 | 3.72 |
| 142.0° | 4.85 | 3.82 | 3.82 |
| 150° | 4.35 | 3.77 | 3.77 |
| 180° | 3.40 | 3.40 | 3.40 |
The fastest heading is not the best one upwind: at 52° the boat sails at 6.07 knots but makes good only 3.74, while at 42.0° it is slower, 5.39 knots, and makes good 4.01, 7.2% more. Downwind the best angle in 6 knots is 142.0°, with 3.82 knots of VMG against 3.40 running dead downwind at 180°. The best angles change with the wind: in 12 knots the guide gives 37.9° upwind and 157.0° downwind. The ORC explains how to use them: the best angle off dead downwind, doubled, is how far you turn when you gybe, and tacking angles are worked out the same way from the best upwind angle.
VMG to a Waypoint
When the mark is not dead upwind or downwind, what counts is the speed toward the mark. The ORC calls it VMC, velocity made good along the course, and notes that two legs, one closer to the wind and one farther from it, are sometimes faster than the direct course. Choose “A waypoint”, enter your course and the bearing to the waypoint, and the calculator takes the angle between them: on a course of 075° with the waypoint bearing 050°, the angle is 25° and 6.07 knots gives 5.50 knots of VMC. The course and the bearing must use the same reference, both true or both magnetic.
Time to the Mark, Current and Leeway
The time to a mark is the distance divided by VMG: 2 nautical miles to a windward mark at 3.74 knots takes 32 min, and at 4.01 knots 30 min. For times at other speeds, the Speed, Distance and Time Calculator works in knots, mph or km/h. The calculator uses your speed and angle through the water, so it leaves out current and leeway; the ORC notes the same of its VMC, which does not take leeway into account. Bowditch defines the speed over ground and the speed made good, the distance between two positions divided by the time between them; a GPS reading of speed and course over ground includes the current.
To find the true wind angle from the wind you measure on board, use the True Wind Calculator. A boat’s top speed through the water depends on its length, as the Hull Speed Calculator shows, and the Sailboat Ratios Calculator compares how much sail it carries for its weight.
Frequently Asked Questions
What is VMG in sailing?
Velocity made good is the part of your boat speed that takes you directly toward the wind or directly away from it, toward a windward or leeward mark. It is boat speed × cos(true wind angle): 6.07 knots at 52° makes good 3.74 knots upwind.
How do you calculate VMG?
Multiply the boat speed by the cosine of the angle between your heading and the true wind. For a waypoint, use the angle between your course and the bearing to the waypoint instead. The calculator does both.
What is the best angle for VMG upwind?
It depends on the boat and the wind. In the ORC’s sample speed guide for a Tripp 40, the best upwind angle is 42.0° in 6 knots of true wind and 37.9° in 12 knots. Sailing faster at a wider angle can make good less: the same boat makes 3.74 knots at 52° but 4.01 at 42.0°.
Is it faster to sail dead downwind?
Often not. In 6 knots of true wind, the ORC sample boat makes good 3.82 knots at 142.0° but 3.40 knots dead downwind at 180°, so gybing downwind at the best angle reaches a leeward mark sooner.
What is the difference between VMG and VMC?
VMG is measured toward or away from the wind, for a windward or leeward mark. VMC, velocity made good to course, is measured toward a mark in any direction, and is what a waypoint calculation gives.
Does VMG include current?
Not when it is worked out from your speed and angle through the water, as this calculator does. Speed and course over ground from a GPS include the current, so VMG worked out from them includes it too.
Sources
- Offshore Racing Congress, ORC VPP Documentation 2026: sect. 7.2 (speeds at true wind angles from 52° to 180° and the optimum VMG upwind and downwind), 7.2.1 (VMC, velocity made along the course), 8.1.1 (the optimum VMG angles for beating and running) (read Oct 22, 2026).
- Offshore Racing Congress, ORC Speed Guide Explanation 2025: sect. 4, Best sailing angles: the best VMG toward a windward or leeward mark, gybing and tacking angles, VMC (velocity made good to course) and leeway (read Oct 22, 2026).
- Offshore Racing Congress, Speed Guide sample (Paragon of Virtue, Tripp 40, 2020): true wind angles, boat speeds and VMG in 6 and 12 knots of true wind (read Oct 22, 2026).
- NGA, The American Practical Navigator (Bowditch), Vol. I (2019): art. 106 (speed, speed over ground, speed made good), art. 908 (track and speed made good from a vector diagram) (read Oct 22, 2026).