Swing Weight Calculator

Measure a club's swingweight from two home measurements, or estimate what a change to head weight, tape, grip, shaft or length will do. Physics on a 14-inch fulcrum, reported to the nearest point with the tolerance shown.

Mode
Length units

Two measurements you can take at home: weigh the whole club on a kitchen scale, then balance it across a ruler edge or a finger and measure from the grip end to that balance point.

Grip, shaft and head assembled. Most irons are 400 to 450 g, drivers 300 to 330 g.

Where the club balances horizontally. Measure to the nearest tenth if you can; every 0.1 inch is worth about a point.

What swing weight is

Swing weight is not how heavy a club is; it is how head-heavy it feels. On the Lorythmic scale the club rests on a fulcrum 14 inches from the grip end and the torque on the head side is read as a letter and number: C9, D0, D1 and so on, each step being 50 gram-inches (1.75 inch-ounces). D0 sits at about 6050 gram-inches.

That definition is why you cannot calculate an absolute swingweight from component weights alone: you also need where each component's mass sits. The previous version of this page tried anyway, with an invented formula, and could be several points out. It has been retired. The measured mode needs only the club's total weight and its balance point, both of which you can take at home, and the estimator works on changes, where lever-arm assumptions are good to about a point.

Measuring the balance point at home

  1. Weigh the assembled club on a kitchen scale that reads in grams.
  2. Balance the shaft across the edge of a ruler, a broom handle or your finger until it sits level.
  3. Measure from the very end of the grip to the balance point, to the nearest tenth of an inch or millimetre.
  4. Enter both numbers. Repeat once; if the balance point moves more than a tenth of an inch, average the two.

How the estimator works

Each change is turned into torque about the 14-inch fulcrum and divided by 50 gram-inches per point. Head weight and lead tape act at the head (assumed 1 inch back from the tip). Grip weight acts on the other side of the fulcrum, about 4.5 inches from the butt, so a heavier grip lowers swing weight. Shaft weight is assumed to balance halfway along the club. Extending a club moves the head, and half the shaft, further from the fulcrum.

Those assumptions reproduce the classic rules of thumb, roughly 2 g of head weight, 5 g of grip weight or half an inch of length per three points on an iron, and show why a driver behaves differently: its head is further from the fulcrum but lighter.

Next in the fit sequence

Swing weight is felt club by club; gapping is judged across the bag. Finish with the map.

Step 6: Bag Gapping CalculatorEnter carry distances, see every gap and overlap, and keep the map on this device.Open

Changed something? Measure it on the course.

A fitting hypothesis only becomes a fit when the numbers back it up. Golfonaut on Apple Watch records your shots and shows carry and dispersion per club, so you can compare before and after any change to length, lie, grip, shaft or swing weight.

Get Golfonaut for Apple WatchMap your carry gaps first

Free on the App Store. Requires an Apple Watch and iPhone. Your fit results stay in this browser; nothing is uploaded.