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Velocity made good

How fast are you gaining ground?

VMG, or velocity made good, measures your progress directly upwind or downwind. On a steady course at 14 knots, angled 45° to the wind, you’re gaining ground upwind at 9.9 knots.

Boat track projected onto the VMG axisA dark dot follows the boat’s zigzag track while a teal dot shows only its synchronized progress directly upwind.BOTTOMTOPVMG
The dark dot follows your ride. The teal dot keeps pace with your progress upwind.VMG = SPEED × COS(ANGLE)
Reading a climb

Same climb. Two different questions.

How fast were your steady upwind spans? How quickly did you finish the climb? Climb span VMG answers the first. Effective Climb VMG answers the second. For a closer look at the turns, see how maneuver stats work.

BOTTOMTOPUPWINDtacks excluded
Maneuvers excluded

Climb span VMG (shown as Sailing only)

Uses every eligible, complete upwind span inside the climb and leaves maneuver time out. One messy tack doesn’t get the final word.

BOTTOMTOPUPWINDtacks count
Maneuvers included

Effective Climb VMG

Divides the ground you gained upwind by the full climb time. Tacks, slow patches, and backslides all stay on the clock.

Climb spans
6.4kn
Whole climb
4.8kn

In this example, eligible steady spans give 6.4 kn Climb span VMG. With the turns and slow patches included, the whole climb averages 4.8 kn.

What the numbers mean

Upwind today
A summary of your stronger, sustained upwind sailing. We select spans on each tack and balance the two sides when both are available. It can also use just one tack.
Best climb · effective VMG
One climb: the ground it gained upwind divided by its full time, every tack and slow patch counted. The Overview names the best one; each climb states its own.
Best segment
The highest-VMG upwind span included in the session’s performance calculation. Focusing a climb does not pick a new best segment.
Span VMG
Your VMG over one complete stable directional span: a steady stretch of the track.
Sailing only
Climb span VMG: windward progress during the included steady upwind spans, divided by their sailing time. Maneuvers stay out.
Course Upwind VMG
Ground gained upwind between Course gates divided by the full gate-to-gate time. Course time expresses that pace over the fixed Course distance.
Live VMG
Your upwind or downwind pace on the Watch while you ride, using its current wind estimate. Analyze recalculates afterward from the complete track.

Reading the wind-relative polar

Reading a polar: riding speed, wind angle and VMGA small arrow on the centerline shows wind blowing down from the top. Starboard spans are teal on the left; port spans are pink on the right. Speed increases toward the outer rings, labeled 14 and 21 knots. The highlighted port span shows 16 knots at 50 degrees to the wind, giving 10.3 knots VMG.14 kn21 kn30°60°50°16 kn10.3 kn VMGStarboardPort
Illustrative spans. The rings show riding speed.

Up points toward where the wind came from. It is not compass north.

Each dot is one upwind span. Its position around the chart shows its angle to the wind; its distance outward shows average riding speed. The rings auto-scale and may not start at zero. They do not show wind speed.

Open a dot to see its VMG and other details. Only eligible, included spans determine the scale and best marker; other dots provide context. Focusing a climb narrows the view, but each dot still represents a span.

How the calculations differ

The polar’s span VMG uses its average speed × cos(angle to the wind). Measured legs and climbs use recorded windward progress divided by the time counted for that metric. Where supported wind estimates vary, movement is projected against the local estimate.

Wind estimates affect angles and VMG. Read how we estimate wind.

Put a number to your next climb.

Foil Run analyzes foiling GPS tracks to show your climbs, turns, runs, VMG, and gear trends. The iPhone + Apple Watch app records sessions and shows live numbers while you ride.

See what Foil Run doesGet the iPhone + Apple Watch app