Almost every golfer who slices has been told the same thing: the face is open, close the face. Some of them have been told the opposite, which is that they are coming over the top and need to swing more to the right. Both pieces of advice are correct for a specific golfer, both are wrong for a different one, and the two golfers cannot tell each other apart by watching the ball finish in the right rough.
They can tell each other apart by watching where the ball starts. That single observation, paired with the direction of the curve, is enough to work out what the club was doing at impact, because the modern ball flight model is simple enough to run backwards. This guide explains the model, gives you a tool that runs it backwards for you, and then gets specific about which practice actually changes which fault.
The two laws that replaced the old ones
For most of the twentieth century, golf instruction taught that the ball started along the swing path and curved away from the face. Under that model a slice meant the club was travelling left across the ball, and the fix was to swing further right. It was a coherent theory. It was also wrong, and Doppler radar showed it to be wrong the moment launch monitors began measuring impact directly rather than inferring it.
What the measurements show is a straight swap of the two roles.
- Law one: the face owns the start line. TrackMan puts it plainly: face angle is the most important number in determining the starting direction of the golf ball, and the ball launches very closely to the direction the face is pointed at impact. The path contributes a minority share. Coaching material derived from TrackMan Academy commonly puts the driver split near 85 percent face and 15 percent path, with the face share falling as loft rises.
- Law two: the gap owns the curve. The ball curves toward the face and away from the path. TrackMan defines face to path as face angle minus club path, and states that the ball should curve toward the face angle and away from the club path whenever that difference is not zero. Nothing else in the swing bends the ball. Not the path on its own, not the face on its own, only the gap between them.
The consequence of law two is the sentence most slicers have never heard. An open face does not slice the ball. A face 5 degrees open with a path 5 degrees out to the right produces a shot that starts right of target and flies dead straight. It is a push, not a slice, and it will end up in the same rough while requiring the exact opposite repair.
Running the model backwards
Because both laws are close to linear, two observations you can make with your own eyes are enough to recover both numbers. Write the model out with w standing for the share of the start line owned by the face:
start direction = w times face angle, plus (1 minus w) times club path. And separately, face to path = face angle minus club path.
Two equations, two unknowns. Rearranged, the face angle is your start direction plus a small correction proportional to the curve, and the path is the face angle minus the face to path. That inversion is the entire tool below. It cannot tell you anything a launch monitor would not tell you better, but it costs nothing, it works on a range or a golf course, and it answers the question that determines what you should be practising.
Shot shape diagnostic
Is your slice an open face or a path across the ball?
Two things about your normal shot are enough to work out what the club was doing at impact: where the ball starts relative to your target, and which way it bends from there. Answer those and this tool runs the ball flight model backwards to recover your face angle and your club path, then tells you which of the two is worth practising. Nothing you enter leaves your browser.
Least loft, most curve for the same mistake, and the club where strike location moves the ball most.
Carry, not total. It sets how many yards a given amount of curve is worth.
Changes the vocabulary only. Left and right below always mean left and right as you look down the target line.
Pull slice
It starts about 12 yards left, bends about 28 yards right, and finishes roughly 16 yards right of your target at 230 yards of carry.
-2.5deg
Closed to the target by about 2.5 degrees at impact.
-5.9deg
Swinging out-to-in by about 5.9 degrees, across the ball toward the left of the target line.
+3.4deg
The gap between the two is what curves the ball. Everything else is where it starts.
This is a path problem, not a face problem.
Your face is within about 2.5 degrees of the target while the path is about 5.9 degrees away from it. That is the pattern almost every self-diagnosed slicer actually has: the face is close to square and the club is travelling across it. Closing the face from here would not fix the curve, it would only start the ball further left and turn one miss into another.
What to work on
- Change what the ball is allowed to hit, not what you are thinking about. Set a headcover or an alignment stick just outside and just behind the ball, angled so a club swinging across the line will clip it and a club swinging down the line will not. Hit half speed shots until you stop hitting the object. A physical constraint rewires a path far faster than a swing thought does, because it gives you an answer on every single ball rather than at the end of the session.
- Fix the trail elbow before the trail shoulder. An out-to-in path usually starts with the trail elbow leaving the body early in the downswing, which throws the club out over the plane before the hands drop. Rehearse the first foot of the downswing with the trail elbow staying in front of the trail hip. The path change follows the elbow, and chasing it with shoulder cues alone tends to produce a stall instead.
- Give your body somewhere to go. Golfers who swing across the ball frequently stop rotating through impact, because a body that stops forces the arms to work across the chest. Feel the lead hip clearing behind you rather than sliding toward the target, and let the trail heel come off the ground. This is the change that holds under pressure once the drills are put away.
What to check on a launch monitor to confirm it
- Face angle: this reading predicts about -2.5 degrees relative to the target line, positive meaning right of it.
- Club path: this reading predicts about -5.9 degrees, positive meaning out to the right of the target line.
- Face to path: about 3.4 degrees, which is the number that actually owns the curve.
- Spin axis: about 16.2 degrees of tilt, which is roughly 28 yards of bend over a 230 yard carry.
- Strike location: check it on every session. A heel or toe pattern will move the ball more than a degree of path will.
These are estimates recovered from two observations you made with your eyes, not measurements. The face and path figures are only as good as your read of the start line, which is the single hardest thing to judge from behind the ball. Treat the direction of the answer as reliable and the decimal place as an illustration, and verify it on a launch monitor before you rebuild anything.
The nine ball flights, and what each one means
Every shot in golf is one of nine combinations: it starts left, straight or right, and it curves left, straight or right. The table is worth reading slowly, because the third column is the one that surprises people. The face is described twice, once against the target and once against the path, and those two descriptions frequently disagree.
| Shot | Starts | Curves | Face at impact | Path at impact |
|---|---|---|---|---|
| Pull slice | Left | Right | Closed to target, open to path | Well out-to-in |
| Pull | Left | None | Closed to target, square to path | Out-to-in, matching the face |
| Pull hook | Left | Left | Closed to target, closed to path | Out-to-in, less than the face |
| Straight slice | At target | Right | Square to target, open to path | Out-to-in |
| Straight | At target | None | Square to target and to path | Neutral |
| Straight hook | At target | Left | Square to target, closed to path | In-to-out |
| Push slice | Right | Right | Open to target, open to path | In-to-out, less than the face |
| Push | Right | None | Open to target, square to path | In-to-out, matching the face |
| Push draw | Right | Left | Open to target, closed to path | Well in-to-out |
Look at the first row. The pull slice, the most common miss in amateur golf, has a face that is closed to the target. The golfer hitting it has been told for years that their face is open, and in the only sense that matters to the ball, relative to the path, it is. But relative to where they are aiming it is pointing left. Which is why closing the face, the advice they were given, makes the shot start further left and finish as a pull rather than a slice. They traded a miss they understood for a miss they do not, and nothing about the actual fault changed.
The three slices, and the three different fixes
Slices divide cleanly into three families once you can see the face and the path separately. Almost every golfer belongs firmly to one of them.
The path slice, which is most of them
The ball starts slightly left of target and bends hard right. Recovered numbers: face within a degree or two of the target, path 4 to 6 degrees out-to-in. This is the pattern that survey data on amateur golfers keeps finding, with typical amateur club paths sitting in the negative 3 to negative 5 degree range.
The face here is fine. The club is travelling across it. Every minute spent on grip and face awareness is a minute spent on the variable that is already correct, which is why so many slicers practise diligently for years without the ball changing. The repair is a path repair, and paths respond to physical constraints and to sequence, not to intentions. A headcover placed just outside and behind the ball gives you a verdict on every swing. A trail elbow that stays in front of the trail hip through the first foot of the downswing changes the delivery. A body that keeps rotating gives the arms somewhere to go other than across the chest.
The face slice
The ball starts well right of target and keeps bending right. Recovered numbers: face 6 or 7 degrees open, path close to neutral or mildly in-to-out. This golfer does have the open face everybody assumes, and for them the standard advice is correct.
The repair usually begins at address rather than at impact. A lead hand rotated too far under the grip makes a square face at impact almost impossible to deliver without a compensating flip. Rotating the lead hand until two or three knuckles are visible is the cheapest degree of face angle in golf, and a large share of golfers in this family have never tried it. After that, lead wrist condition through impact does the rest, and start line is the scoreboard: score a session on where the ball starts and ignore where it finishes.
The strike slice
The ball does something that does not fit either pattern, or the curve is far larger than the swing seems to justify. Recovered face to path comes back at 9 or 10 degrees or more, which is more than most swings produce.
This is gear effect. Contact away from the middle of the face makes the head rotate around its own centre of gravity and the ball gears off that rotation. Heel contact adds fade and slice spin. Toe contact adds draw and hook spin. The effect scales with head size and ball speed, so it is largest with a driver, which is exactly the club most people are holding when they decide they have a slice. A golfer who repeatedly finds the heel will slice the ball with a perfectly acceptable path, and no path drill will touch it. Foot spray or impact tape for one session is a five dollar test that saves a season of misdirected practice.
Why the same swing slices a driver and not a wedge
Spin axis is the tilt of the total spin on the ball relative to the horizon, and that tilt is what bends the flight. A given amount of sideways spin tilts the axis a lot when backspin is low and very little when backspin is high, because the backspin dominates the total. TrackMan publishes the yardage relationship directly: roughly 10 degrees of spin axis is about 11 yards of curve on a 150 yard shot and about 15 yards on a 200 yard shot.
Put the two together and the same face to path produces wildly different results depending on what is in your hands. Using TrackMan's worked driver example, about 2 degrees of face to path produces about 19 yards of curve under tour driver conditions, which is roughly 4.7 degrees of spin axis per degree of face to path. Scale that by typical backspin and the picture looks like this:
| Club | Typical backspin | Spin axis per degree of face to path |
|---|---|---|
| Driver | 2,700 rpm | 4.7 degrees |
| Fairway wood or hybrid | 3,600 rpm | 3.5 degrees |
| Mid iron (6 to 8) | 6,300 rpm | 2 degrees |
| Wedge | 9,200 rpm | 1.4 degrees |
A driver bends about 3.4 times more than a wedge for the identical mistake, and about 2.3 times more than a mid iron. Your wedges are not better than your driver. They are quieter about the same fault. This is also why the wedge that curves violently is almost always telling you about strike location: producing that much curve with 9,200 rpm of backspin needs a face to path most golfers never reach.
What to practise, in order
Once you know which family you are in, the sequence matters as much as the drill. Three rules hold across all three families.
- One variable at a time. Changing the face and the path in the same session produces a two-way miss, which is worse than a predictable slice and far harder to diagnose. Fix the larger error against the target line, leave the other alone, and accept that the ball will get uglier before it gets better.
- Path before face when both are off. A path is slower to change and more permanent once changed. A face compensation applied to an uncorrected path is a timing pattern, and timing patterns need re-establishing every time you take two weeks off.
- Score the start line, not the finish. Because the face dominates start direction, counting how many shots start inside a narrow corridor is a face angle measurement you can run without any technology at all. Most golfers have never scored a single session this way, and it is the most informative free feedback available.
A useful session structure is 20 minutes on the constraint drill for your family at half speed, 15 minutes alternating between the drill and a normal swing so the change has to survive contact with your real tempo, and 15 minutes hitting to an actual target and scoring only the start line. Our indoor practice plan guide goes further into how to build blocks like that, and the strokes gained diagnostic is the honest way to find out whether your slice is actually the thing costing you the most strokes, which for a surprising number of golfers it is not.
Why a range makes this diagnosis harder than it needs to be
The diagnostic on this page needs two clean observations, and a driving range degrades both of them in ways that are easy to miss.
- Range balls curve less. They are built durable and low spinning, so the curve you observe understates the curve your premium ball produces on the course. A pattern that looks like a gentle fade on a range mat can be a genuine slice on Saturday.
- Wind rewrites the curve. Any crosswind adds or subtracts yards of apparent bend, and it changes between the start and the end of your session without announcing itself.
- Nobody is measuring strike. The one variable that can invalidate the entire diagnosis is the one a range gives you no information about.
- Start line is genuinely hard to judge. From behind the ball, the first 30 yards of flight happen quickly and your eye tends to record where the ball ended rather than where it left. This is the single largest source of error in the tool above.
A launch monitor removes all four at once. It reports face angle and club path as measured numbers rather than as inferences, it reports spin axis so the curve is quantified rather than remembered, and the better systems report strike location on the face so gear effect stops being a guess. That is the difference between a theory about your slice and a fact about it. The simulator versus driving range comparison is honest about the situations where the grass range still wins, and it is worth reading before assuming indoor practice is strictly better.
Where Framegolf fits
Framegolf is a members-focused indoor golf club at 3375 Robertson Pl in Los Angeles, on the Culver City border, with four private bays. For this particular problem a private bay is close to the ideal setting, and it is worth being specific about why rather than making a general claim about indoor practice.
Diagnosing a slice takes repetition under identical conditions. You need to hit the same club to the same target enough times to see a pattern rather than a sample, with the same ball every time, no wind, and no queue behind you while you work through 15 half speed swings that go nowhere. A private bay with a launch monitor gives you face angle, club path, face to path and spin axis on every single shot, which turns the estimate from the tool above into a measurement, and lets you watch the number move during the session rather than guessing afterwards.
The honest limit is that a bay will not teach you to hit the shot from a sidehill lie in the rough, and no amount of measured practice replaces playing golf. Founding member access will begin at the end of August 2026, and public membership opens in September 2026. If you want the cost side before the practice side, the LA simulator cost guide covers hourly bay rates across the city and where membership math overtakes paying by the hour, the club fitting guide covers when equipment is genuinely contributing to a curve rather than reporting it, and membership pricing is here. Drive times from across the Westside are on the neighborhoods page.
The short version
The ball starts where the face points and curves away from the path. Put those two facts together and your normal shot tells you everything, so long as you record where it started rather than only where it finished.
Most golfers who slice do not have an open face relative to their target. They have a face close to square and a club travelling several degrees across it, which leaves the face open relative to the path and bends the ball right. For them, closing the face is a downgrade, not a fix. A smaller group genuinely does have an open face, and for them the common advice works. A third group has neither and is simply missing the centre of the club.
Those are three different practice sessions. The only thing standing between you and the right one is a single observation you have probably never deliberately made.
Sources
- TrackMan, What is Face Angle. The source for face angle as the dominant control on starting direction, and for the sign convention used throughout this guide.
- TrackMan, What is Face to Path. Defines face to path as face angle minus club path, states that the ball curves toward the face and away from the path, and publishes the worked driver example used to calibrate the tool on this page.
- TrackMan, What is Club Path. Definition of club path and the in-to-out and out-to-in vocabulary.
- TrackMan, What is Spin Axis. Definition of spin axis and the published curvature examples at 150 and 200 yards that set the yardage arithmetic here.
- TrackMan Help Center, Practice data parameter definitions. The formal parameter list, including face angle, club path and spin axis as measured rather than as described.
- PGA Academy (Australia), Starting Line: Path or Face? The clearest published statement of the approximate percentage split between face and path in starting direction, drawn from TrackMan Academy material.
- GolfWRX, Use the new ball flight laws to understand your tendencies. A practitioner walkthrough of what changed when Doppler radar replaced assumption.
- Rapsodo, How gear effect works in golf. Explains why the strike location on the face adds curvature independently of the swing.
- Andrew Rice, Understanding off-center strikes. Measured examples of what heel and toe contact does to launch, spin and curvature on a driver.
- Golf.com, Is it better to miss a drive on the heel or the toe? Robot testing of the same question, with the distance cost of each miss.
Questions people ask
What actually causes a slice in golf?
A slice is caused by the club face pointing to the right of the direction the club head is travelling at impact, for a right handed golfer. That difference is called face to path, and it is the only thing that curves the ball. Note what is not in that sentence: an open face by itself does not slice the ball. A face 5 degrees open with a path 5 degrees out to the right produces a dead straight shot that starts and stays 5 degrees right of target. What slices the ball is the gap. This is why the most common slice pattern in amateur golf is a face that is nearly square to the target with a club path swinging well left of it, which leaves the face open relative to that path even though it looks square to the golfer.
Why does my ball start left and then curve right?
Because those two things are controlled by different variables. The ball starts very close to where the face is pointing, so a ball that starts left means the face was pointing left of your target at impact. It then curves right because the club path was even further left than the face was, leaving the face open relative to the path. That shot is a pull slice, and it is the single most common ball flight in amateur golf. The important consequence is that the standard advice for a slice, which is to close the face, makes this shot worse rather than better. Closing the face on a pull slice starts the ball further left and reduces the curve, so it turns a slice into a pull.
Should I fix my club face or my club path first?
Compare each one against the target line rather than against each other. If your face is within a degree or two of the target and your path is 5 degrees off it, the path is the thing that is wrong even though the face is what is producing the curve. If your path is close to neutral and the face is 6 degrees open, the face is the problem and path drills will not touch it. The diagnostic on this page makes that comparison for you. When both are similarly off, work the path first: it is slower to change but it holds, whereas a face compensation applied to a bad path is a timing pattern that has to be re-established every round.
Is the old ball flight explanation wrong?
Yes, and it was taught for decades. The old model said the ball started along the swing path and curved away from the face, so a slice meant an out-to-in path and the fix was to swing more to the right. Doppler radar measurement showed the opposite: the ball starts very close to where the face points and curves away from the path. The practical difference is enormous. Under the old model, a ball starting left meant a path swinging left. Under the measured model, a ball starting left means a face pointing left, which might be paired with a path that is fine or a path that is terrible, and you cannot tell without also reading the curve.
How much does the face control the start direction, exactly?
TrackMan states that face angle is the most important number in determining the starting direction and that the ball launches very closely to the direction the face is pointed, without publishing a single percentage on that page. Coaching material derived from TrackMan Academy commonly puts the driver figure near 85 percent, with the remaining share going to the path, and puts the face share lower as loft increases. This guide uses 85 percent for a driver, 78 percent for a mid iron and 72 percent for a wedge, which are approximations rather than measurements, and the arithmetic here is written so you can see exactly where they enter.
Can a bad strike make me think I have a slice?
Very much so, and it is the most common way a diagnosis like this one goes wrong. Contact away from the centre of the face makes the head rotate around its own centre of gravity, and the ball gears off that rotation. Contact toward the heel adds fade and slice spin, contact toward the toe adds draw and hook spin. The effect is largest on a driver because the head is large and the ball speed is high. A golfer who strikes the heel repeatedly will see a slice that has nothing to do with their path, and every path drill in the world will fail to fix it. Check strike location with impact tape or foot spray before you rebuild a swing.
Why does my driver slice but my wedge does not?
Backspin. Spin axis is the tilt of the ball's total spin, and it is the tilt that curves the ball. The same amount of sideways spin tilts a low spinning driver shot far more than it tilts a high spinning wedge shot, because the backspin dominates the total. A driver at roughly 2,700 rpm and a wedge at roughly 9,200 rpm are two different instruments for the same swing fault. The wedge hides it and the driver exposes it. That is also why a wedge that curves dramatically is usually reporting a strike problem rather than a path problem, and the tool on this page flags exactly that case.
Can I diagnose this at a driving range?
Partly, and less well than you would hope. You can see the start line and the curve on a clear day with a real target, which is all the diagnostic on this page needs. What a range makes very hard is honesty over time: range balls curve less than premium balls because they are built to spin less, the mats hide fat contact, wind changes the curve you observe from one hour to the next, and nobody is measuring strike location. A launch monitor removes all four of those problems at once by reporting face angle, club path and strike directly, which turns a diagnosis into a measurement.