Club Fitting Engine

Enter a few 7-iron shots from any launch monitor and get one answer per spec — head and loft, shaft, lie, length and grip.

Session

Handedness

Shots

Launch monitor

Your irons — the one you hit

Looking to change the TYPE of iron? Leave this alone and the fitting works from what you play. Answer it and the head row answers your question instead — with what the change costs, taken from this session.

The club you hit

Lie, loft and length are entered as a difference from the model’s standard, because standard is what the database already knows and the difference is what a golfer knows. The figure it works out to is shown under each one. “Don’t know” is a real answer and is treated differently from “standard” — the engine assumes standard so the rules can run, then says so and lowers its confidence.

Lie

Loft

Length

Swing weight

Shaft

Flex

Shaft weight (g)

Grip

Grip size

Extra wraps

Grip size is fitted from hand length, measured from the wrist crease to the tip of the middle finger. Without that measurement the engine will not guess a size — a grip size inferred from height or handicap is invented, so it says so instead. Glove size works as a coarse fallback.

Hand length (in)

Glove size (fallback) Only used when hand length is blank. Two golfers in the same medium glove can differ by nearly 3/4 in.

Height — feet

and inches

Ball hit

Your driver

Its loft (°) Needed before the engine can tell you whether your hosel already covers the change, which is usually cheaper than a new driver.

Wedge

Swing effort

Home turf

Speed tier

No launch monitor, no numbers. Answer what the ball actually does and the engine works back to equipment. Everything it concludes is an INDICATION rather than a measurement, and it says so — it is enough to stop you buying the wrong thing, not a substitute for a session.

Your usual shot shape

Where the ball STARTS, the first 30 yards — before any curve This is the question that separates a lie problem from a swing-path problem, so it is worth watching for a few shots before answering.

Flight height

On a green of normal firmness, your mid-iron shots

Wind hurts my ball flight noticeably more than it hurts the people I play with

Roughly how far does your 7-iron CARRY, in yards? Your average, not your best one. Without it the shaft row cannot be fitted at all, and with it the number is still the weakest input here.

What the irons you play now look like Look down at the club at address. This is a CATEGORY, not a measurement — it carries the typical loft and forgiveness of its class, which is why naming the exact model below is worth more.

Or pick the exact iron, if it is in the database With the model named, the engine reads its real 7-iron loft, length and forgiveness tier and checks them against the ball flight you just described — which is how it can tell “the loft is the cause” from “the loft is already fine.” It overrides the category above.

Looking to change the TYPE of iron? A want, not a symptom. The engine answers it and then says plainly what the ball flight you just described has to say about it.

Shaft flex, as printed on it Worth knowing, but it settles less than it looks. There is no industry standard for flex — one maker’s S measures like another’s X — and not one iron shaft in this database publishes a swing-speed band to check it against.

Or the exact shaft, if it is in the database This is the one that does the work. With the model named, its published launch and spin ratings get checked against the ball flight you described — which is how the engine can tell “the shaft is part of this” from “the shaft is already doing its job, look elsewhere.”

Height — feet

and inches

Hand length (in)

or glove size

Hand length is wrist crease to middle fingertip. It fits the grip; height fits the length.

The grip on them now

And its size Without these the grip row can only say what to fit, never whether you are already on it.

Joint pain, arthritis or high grip pressure Plays wet, or sweats heavily Plays without a glove Over-active trail hand, or a hook miss This is a PUTTER grip question

Carry distances only. Leave a club blank if it is not in the bag. No launch monitor needed.

7-iron readings

Spin spread (rpm)

Loft gap to next (°) An equipment fact, not a shot reading, so it is asked once.

Consistent start bias Absolute, as the monitor reports it. The engine flips the meaning by handedness.

Opens the face a lot / plays flops Struggles from sand specifically

Your fitting

Show rule codes

Your fitting is ready.

A grad student built this and gave it away, because a fitting that costs more than the clubs never made much sense. If it was worth something to you, a few dollars keeps it running and pays for the next set of clubs to get added to the database.

And if not, that is completely fine. Nothing is locked.

Card or PayPal Cash App

What this is. A fitting engine that shows its working. Every row names the rule behind it, the window it was measured against and how confident it is — and says plainly what your session could not settle.

Your numbers stay here. Everything runs inside this page. Nothing you type is sent anywhere and nothing is saved.

It is still being built. Treat it as a strong second opinion rather than a replacement for a session with a fitter, and check anything surprising before you spend money on it.

How the rule set was tested

What this is. A prototype of all four fitting paths, built to test the rule set rather than to be shipped. Running adversarial cases through it found eighteen contradictions in a spec that read as complete — five on the iron path, nine across driver and wedge, four in gapping — in nine distinct classes: gates that stated their precedence only in prose, delivery faults that failed to suppress their own consequences, free checks buried under equipment advice, feasibility vetoes sitting beside the advice they contradict, confirmatory rules restating a finding, a modifier presented as a separate answer, and a generic rule firing alongside a specific one on the same finding with contradictory framing — one telling the golfer to close a gap while the other told them it mattered less. All are fixed here and recorded in the workbook's Rule Precedence and Gapping tabs.

Two paths need no launch monitor at all. No data asks what the ball actually does — shape, where it starts, flight height, whether shots hold the green, whether wind hurts more than it should — and works back to equipment, adding length from height and grip size from hand length. Every row it produces is an INDICATION rather than a measurement and says so, and it ends by listing what one launch monitor session would settle that it cannot. It separates delivery from equipment the way the measured paths do: a ball that starts left and curves right for a right-handed golfer is an out-to-in path, so it blocks the lie answer instead of producing one — while the mirror image, starting right and drawing back, is the shot a good player is trying to hit and gets no change at all. Where two answers contradict each other — shots running off the green needs more height and spin, wind hurting too much needs less — it names the contradiction rather than splitting the difference.

Gapping is the other. Carry distances are its only input, which makes it the one module a golfer can use without booking a bay. Lofts are optional there and enter only to explain why a gap exists — a missing loft downgrades the explanation and never blocks the analysis. Windows and specs carry their source confidence flags. Shaft candidates are drawn from 128 shafts across eight brands: where the workbook records no value for a criterion, or flags a model CONFLICTED because it behaves differently by tip configuration, that shaft is excluded rather than ranked on a guess.