Launch Monitor Comparison: Which Numbers Are Measured and Which Are Guessed
Every launch monitor on the market derives carry distance from a flight model, and most of the cheaper ones derive clubhead data and spin as well. The real buying question is which metrics the sensor physically measures and how much room it needs to do it — a radar unit typically wants around eight feet behind the ball plus eight to thirteen feet of flight in front, while a camera unit sits a foot to the side and needs almost nothing. That difference is what rules most units out of a garage.
By the All Birdies Editorial Team
Ball speed and launch angle are measured on essentially every unit worth buying. Spin is measured on some and modelled on others. Carry distance is derived on all of them, without exception, because no launch monitor watches the ball land.
That is the buying decision, and it is not a brand decision. A unit that measures spin directly and one that infers it from a smash-factor model can print identical-looking numbers to one decimal place, and only one of them is telling you something about the shot you just hit.
The second half of the decision is geometry. Radar needs to watch the ball fly for long enough to resolve it, which means depth behind the hitting position and depth in front of it. Camera-based units measure in the first few inches of flight and need almost nothing. Golfers who buy on features and then measure the garage discover this in the wrong order.
One more thing, which belongs on a site that grades equipment against published rules: this is the only category here with no governing register at all. Driver heads get pendulum-tested and listed. Balls get submitted and listed. Launch monitor accuracy is checked by nobody, and the manufacturer's claim is the only claim there is.
Two ways to see a golf ball
Doppler radar sits behind the ball or behind the player and tracks the object in flight by the frequency shift in the returned signal. It sees the ball over a stretch of its flight, which is why it produces genuine spin and, on higher-end units, genuine club delivery data. It is also why it degrades indoors: a ball that hits a net eight feet away has given the radar a very short look.
Photometric units are cameras. They sit beside the ball or above it, fire a burst of high-speed frames through the first few inches after impact, and calculate everything from the images. Spin comes from tracking markings or the dimple pattern between frames. Because the measurement happens immediately, a short indoor flight costs them nothing, which is the single biggest reason simulator builds favour them.
Hybrids run both. The camera handles the ball at launch and the radar handles the club, or the other way round, and the combination covers the weakness in each. That is the direction the mid-market has moved.
Neither technology is better in the abstract. Radar is better outdoors and on a range, where it can watch a full flight. Cameras are better in a room. The wrong choice for your space produces bad data, not slightly worse data.
Measured or derived, metric by metric
Metric Doppler radar Photometric camera Hybrid What to know Ball speed Measured Measured Measured The foundation number. Everything downstream leans on it Launch angle Measured Measured Measured Camera measures it in the first inches; radar needs a stretch of flight Launch direction Measured Measured Measured Reliable across the board Spin rate Measured with enough flight, degraded without it Measured from markings or dimple pattern Measured by the camera side This is where indoor radar into a net falls down Spin axis or side spin Measured on better units, modelled on cheaper ones Measured Measured Often reconstructed from launch direction and a curvature model Clubhead speed Measured Derived from ball speed unless a club sensor is fitted Measured The most commonly modelled number on budget units Club path Measured on dual-radar units only Add-on club tracking only Varies by unit Check before you assume it is real Face angle Measured on dual-radar units only Add-on club tracking only Varies by unit As above Angle of attack Measured on dual-radar units only Add-on club tracking only Varies by unit The metric most worth having and least often measured Smash factor Derived Derived Derived It is ball speed divided by clubhead speed. If one of those is modelled, so is this Carry distance Derived Derived Derived A flight model fed by the measured numbers. Nobody measures carry Total distance Derived, plus a roll model Derived, plus a roll model Derived, plus a roll model Roll assumptions differ wildly between brands and are rarely published Use this before you compare units at all — decide which metrics you actually need measured, then only shortlist hardware that measures them. A modelled number is not worthless, but it cannot tell you anything the model did not already assume. The clubhead speed row deserves a moment. A photometric unit with no club tracking sees the ball leave at 148 mph, applies an assumed smash factor for the club you told it you were using, and prints a clubhead speed of about 100 mph. If your strike was off-centre, your real clubhead speed was higher and your real smash factor lower, and the screen will never say so. It is a plausible number generated from a single measurement.
This is not a scandal and the manufacturers do not hide it. It is a scandal that so little consumer coverage separates the two columns.
The comparison chart
Unit Sensing technology How spin is obtained Club delivery data Per-metric tolerance disclosure Conformance Grade TrackMan 4 Dual doppler radar with optical assist Radar-measured given enough flight Full delivery data measured Published tolerances per metric A Foresight GCQuad Quadrascopic photometric Camera-measured from ball markings Measured, with the club head add-on only Headline claims, limited per-metric figures B Uneekor EYE XO Overhead photometric Camera-measured, marked or unmarked depending on model Measured Headline claims, limited per-metric figures B Bushnell Launch Pro Photometric, Foresight sensor Camera-measured Ball data standard, club data on the higher subscription tier Headline claims only B SkyTrak+ Photometric with doppler radar Camera-measured Measured for speed, path and face to path Headline claims only B FlightScope Mevo+ 3D doppler radar Radar-measured; a metallic marker sticker is strongly advised indoors Measured for several club metrics Partial, and condition-dependent C Full Swing KIT Doppler radar Radar-measured Clubhead speed measured, delivery data limited Limited C Rapsodo MLM2PRO Camera and radar hybrid Camera-measured with the brand's marked balls, modelled without them Clubhead speed measured, delivery data limited Limited C Garmin Approach R10 Doppler radar Radar-derived, and short indoor flight degrades it badly Clubhead speed measured, the rest modelled Little published per-metric detail D Sensing technology is a hardware fact and will not change. Spin handling, club data and subscription tiers move with firmware and licensing, so treat the last three columns as a prompt to go and read the current spec sheet rather than a permanent rating. The Conformance Grade here is weighted almost entirely toward disclosure, because there is nothing else to weight it against. A unit gets an A for publishing what it measures, how it measures it and what tolerance it holds. It gets a D for printing eleven metrics on a phone screen without ever saying which two of them came from a sensor.
That is a deliberate choice and it does penalise some genuinely useful cheap hardware. A budget radar unit that reports ball speed and clubhead speed honestly is a good purchase for a golfer who wants to track speed over a winter. It just should not be sold as a spin instrument, and the grade reflects the gap between what the box implies and what the sensor does.
Space is what actually rules a unit out
Unit Where the sensor sits Distance from the ball Flight needed in front Ceiling height Practical outdoors TrackMan 4 Behind the player About 8 ft behind the ball 10–13 ft to the screen indoors 10 ft and up Yes, and this is where it is strongest Full Swing KIT Behind the player About 6–8 ft behind 8–10 ft 9–10 ft Yes FlightScope Mevo+ Behind the ball About 7–8 ft behind About 8 ft 9–10 ft Yes Garmin Approach R10 Behind the ball About 6–8 ft behind About 8 ft to a net 9 ft Yes Rapsodo MLM2PRO Behind the ball About 7–8 ft behind About 8 ft 9 ft Yes Foresight GCQuad and Bushnell Launch Pro Beside the ball About 12–15 in to the side 8–10 ft, for safety rather than measurement 9 ft Yes SkyTrak+ Beside the ball About 12–16 in to the side About 8 ft, for safety 9 ft Yes Uneekor EYE XO Overhead, fixed ceiling mount About 8–10 ft above the ball About 8 ft, for safety 9.5–10 ft, and it must be permanently mounted No Measure your room first, then shortlist. Add the two distance columns together to get the total depth the unit needs, and compare that against the actual dimension from the back wall to the screen. Do the addition and the picture changes. A radar unit wanting eight feet behind the ball and ten feet of flight in front needs eighteen feet of usable depth. A camera unit beside the ball needs about nine or ten, almost all of it for safety rather than for the sensor. A standard single garage in the UK is often around sixteen feet deep internally, which is the exact reason so many home simulator builds end up photometric.
Ceiling is the other quiet killer, and the figure that matters is not your height. It is the height of the clubhead at the top of your driver backswing, which for a six-footer is comfortably over nine feet. Stand in the space with a driver and make a slow full swing before you spend anything. Most owners who skip that step find out with a light fitting.
Width gets forgotten too. A left-handed golfer sharing the space with a right-hander needs a unit that can be repositioned quickly, and overhead and side-mounted sensors handle that very differently.
Carry is derived on every single one of them
It is worth saying plainly because so much marketing is built on top of it. No consumer launch monitor measures how far the ball went. Every carry number on every screen is a physics model taking measured launch conditions and predicting a flight, and the models differ.
Two units given identical measured inputs can disagree on carry by several yards because one assumes sea level and one asks for altitude, or because one models a standard ball and one lets you choose. Neither is lying. They are different models.
This matters most for gapping work, where the whole exercise is comparing carry numbers across clubs. The good news is that internal consistency is what you need there, and every unit is internally consistent with itself. Use one unit for a whole gapping session and the gaps will be right even if the absolute yardages are three yards optimistic across the board.
It matters least for speed training and strike quality, where ball speed and smash factor are what you are watching and both are measured. If that is your use case, buy the cheapest unit that measures those two honestly and stop reading spec sheets.
Switching one on during a round is a Rule 4.3 problem
A launch monitor is practice equipment. Rule 4.3a permits a distance-measuring device for measuring distance, and nothing more; gauging other conditions that affect play, or using equipment that might assist in making a stroke, falls outside what the rule allows.
A launch monitor is not a distance-measuring device in the sense the rule means. It is a swing-and-ball-data instrument, and switching one on during a competition round to read your numbers puts you squarely in Rule 4.3 territory. The penalty for a first breach is the general penalty — two strokes in stroke play, loss of hole in match play. A second breach is disqualification.
Practice rounds are a different matter and there is no issue there. Between rounds on a range during a competition, the constraints come from the practice rules and from whatever the Committee has published, so read the conditions of competition rather than assuming.
The distinction to keep in your head is simple. A device that tells you how far away the flag is may be permitted, subject to any local rule the Committee has adopted. A device that tells you what your swing just did is not.
How the Conformance Grade is applied in this category
Grade What it means across the site The launch monitor version A The governing limit is published and the product's position against it can be verified Per-metric tolerances published, sensing method stated, spin measured rather than modelled B The limit is published but the headroom is not disclosed Headline accuracy claim only, spin measured, space requirements published C Status depends on conditions the owner controls Spin depends on markers, lighting or flight length, and accuracy varies with setup D Status cannot be verified from anything published No per-metric tolerance anywhere, and the measured-versus-derived split is never stated F Fails the governing limit, or is legal only outside the competition you are entering Reserved for devices carried in play whose non-permitted functions cannot be locked out under Rule 4.3 Use the grade to decide how much of the spec sheet to believe, not to rank the hardware — a C-grade unit can be the right buy for a golfer who only needs the two metrics it measures well. Quick answers
- Camera units for indoor spaces, radar for outdoors and ranges, hybrids if you genuinely do both.
- Total depth needed is the space behind the ball plus the flight in front. For radar that sum is usually sixteen to twenty feet.
- Nine feet of ceiling is a minimum, not a target, and it should be measured with a driver in your hands rather than a tape.
- Spin measured from ball markings is real. Spin inferred from ball speed and an assumed smash factor is a model with a decimal place on it.
- Carry is derived everywhere. Internal consistency is what makes a unit useful for gapping, not absolute accuracy.
- Using one during a competition round is a Rule 4.3 breach: general penalty first time, disqualification the second.