PutterSense
In development
Your phone goes in a holder on the putter shaft, and PutterSense reads the stroke from the sensors already inside it. Nothing to buy, nothing to pair. Just face angle, path, pace and tempo, every stroke.
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No waiting
No pairing ritual, no waiting for a report. Every putt is measured, checked and on your phone before you have picked the ball out of the hole. Instant results, every single time, are how the perfect stroke actually gets built — one putt, one reading, one correction, and then the same thing again until it is yours.
The problem
Nobody three-putts on purpose. But the difference between the one that drops and the one that burns the edge is often less than a degree of face angle: an error far too small and far too fast for anyone to see, feel, or remember five seconds later.
So you guess. You change your grip, your stance, your putter, your read. And you never find out whether any of it helped, because the only feedback golf gives you is whether the ball went in, which on a six-footer is barely feedback at all. Hole a bad one, learn nothing. Miss a good one, learn something wrong.
What it actually does
Launch monitors watch the ball and infer the rest. PutterSense does the opposite: it reads the putter itself, sample after sample through the stroke, and reconstructs where the head was and what the face was doing at the exact millisecond of impact.
That's possible because a putter is rigid. Track the attitude of one point on the shaft precisely enough, and the geometry gives you everything at the other end: a club length away, at the face, where it actually matters. No cameras, no tripod, no marked balls, no net. Your phone, a holder, your putter, and the green you were going to practise on anyway.
How it works
Into the holder, just below the grip, lengthwise. Fits any putter — no alignment marks, no re-gripping. It has to be rigid, and that is the one part worth getting right.
It wakes when you do and finds every stroke on its own. No buttons between putts, no app to poke at, no rhythm to break.
Your putt appears before you've reset: the numbers, the arc, and a score out of five you can watch move session to session.
A putt, read
Every putt is quoted from ten feet, so a tap-in and a lag putt land on the same scale and a session actually compares. You don't get a wall of telemetry. You get the number that explains the miss, and a score out of five that tells you how much it cost you.
Here, the face was 0.77° open at impact. That alone sent the ball nearly two inches right of centre. The path was fine. The tempo was fine. One number explains the whole putt, and it's the number nobody can feel.
Putt 7 of 12● read
3out of 5
Would finish 1.7 in right of centre from 10 ft.
A real reading, produced by the engine running against a simulated stroke.
What you'll learn
The one that matters most, by a mile. The face decides where the ball starts; the path barely gets a vote. Measured to a fraction of a degree.
Whether you're swinging across the ball, and whether the face is square to that swing or fighting it. The two together explain the start line completely.
Backswing against through-stroke, as a ratio. The best putters keep it identical on a three-footer and a forty-footer. Now you can see whether yours holds.
How hard you actually hit it, and how far it would have run out. Most three-putts are a speed problem wearing a line problem's clothes.
Every putt converted to inches left or right from ten feet, so "that felt good" becomes a number you can compare to last Tuesday.
Session on session, is your face angle getting tighter? That is the only question practice is meant to answer, and almost nothing else can answer it.
Where this is
Two things at two different stages, and it is worth being straight about which is which. What runs today is a web app: your phone goes in a holder on the shaft and the stroke is read from the accelerometer and gyroscope already inside it. It reads a real stroke on a real green, and it is not open yet — the form above is how you get in when it is.
What is being built is a sensor that lives on the club instead, because a phone samples about sixty times a second and the numbers get better the faster you look. It does not talk to your phone yet. When that works, this page will say so — and not before.
Why you can trust the number
Plenty of gadgets will hand you a confident figure for anything you do in front of them. This one checks its own work first: every stroke is tested against the physics of a real putting stroke before it's graded, and one that doesn't pass is refused rather than guessed at.
You will never be shown a face angle of 0.4° by a device that had no idea. That's a strange thing to put on a website, and it's the reason the numbers are worth changing your stroke over.
Both figures come from our own error budget: the engine run against simulated strokes whose true answer is known, at a phone's sample rate and at the sensor's. They are the floor, not a promise — a real stroke on a real green will be worse than either.
PutterSense is in development and there's nothing to buy yet. Leave your address and you'll know the moment there is, plus first refusal on the early run.
One email when it's ready · nothing else, ever