Tenths of a Degree Decide the Four-Footer
Everybody knows short putts are unforgiving. Very few golfers have seen the numbers written down, and the numbers are more brutal than the reputation.
Start with the geometry, because it is the part nobody argues with. A ball launched one degree away from a straight line drifts by the tangent of one degree multiplied by the distance travelled. Over four feet, that works out at roughly eight tenths of an inch.
The cup is four and a quarter inches across. The ball is a shade over one and two thirds. Subtract one from the other and the ball's centre has about two and a half inches of total width to work with, which means roughly one and a quarter inches of error available in either direction.
Divide that by eight tenths of an inch per degree and you arrive at the headline: about one and a half degrees of face error in either direction, on a dead straight four-footer, at a pace that just reaches the hole. That is the whole allowance.
Then Reality Shrinks It Further
Three things eat into that allowance before you have even stroked the ball.
Pace. The figure above assumes the ball is dying into the cup. Hit it firmly enough to take the break out and the ball will not drop from the edge; it will spin out. Every increment of pace above holing speed narrows the effective target, and on quick desert greens in spring most golfers are putting harder than they think.
Read. A four-footer with three inches of break needs the ball started at a different aim point, and any error in judging that break comes straight out of the same one-and-a-quarter-inch budget. Face error and read error are additive, and they are indistinguishable from the outside.
Strike. Contact away from the centre of the face twists the head slightly at impact. A modern high-inertia mallet limits this well; a small blade does not. Half an inch of heel contact on an unforgiving head is worth a few tenths of a degree on its own.
| Putt Length | Drift per Degree | Face Budget, Straight Putt |
|---|---|---|
| 3 ft | 0.63 in | ±2.0° |
| 4 ft | 0.84 in | ±1.5° |
| 6 ft | 1.26 in | ±1.0° |
| 8 ft | 1.68 in | ±0.7° |
| 12 ft | 2.51 in | ±0.5° |
The right-hand column is the budget for a perfectly read, perfectly paced, perfectly struck putt on a flat surface. Nobody gets to spend all of it, which is why the practical figure most golfers should aim for is holding face error inside a single degree.
Why This Changes How We Fit
Because it means the only useful thing a putter fitting can do is reduce the spread of face angles you deliver. Not the average — the spread. A golfer whose face averages perfectly square but varies by four degrees either way is going to miss a lot of four-footers, and their average will look excellent on a summary screen.
We therefore log every stroke individually and look at the width of the distribution, the same way we treat start-line spread with a driver. Sessions where the average barely moves but the spread halves are the best sessions we run, and they are the ones golfers are most surprised by, because nothing felt dramatic while it was happening.
It also explains why we spend so long on aim before we spend any time on heads. A golfer aiming a degree and a half off has already spent their entire budget standing still. No head shape fixes that; only measuring it does.
Two Things Worth Doing Tomorrow
First, putt to a tee rather than a hole for ten minutes. A hole rewards a ball that catches the edge and falls in, which flatters your face control. A tee gives you no such mercy and shows you your actual dispersion.
Second, do it at four feet rather than at twenty. Long putts feel more productive and teach you about speed, which is genuinely important, but the face is easiest to observe when the target is close enough that a small error is visible immediately.
Neither of those requires any equipment or any money. They will, however, tell you fairly quickly whether your putting problem is a face problem, at which point it becomes worth measuring properly.