How golfity Calculates Strokes Gained Without GPS Sensors

Most strokes gained products sell you hardware first. Arccos puts a sensor in every grip, Shot Scope straps a watch on your wrist, and both rely on GPS to log where each shot started and finished. golfity strokes gained works without any of that. There are no sensors to screw in, no batteries to charge, and no GPS tags to lose in the rough.

The math behind strokes gained doesn’t actually need a sensor. It needs two things for every shot: how far you were from the hole, and what you were hitting from. Once golfity has those, the same model the PGA Tour uses does the rest.

What strokes gained really requires

Strokes gained compares your shot to a benchmark. The benchmark answers one question: from this exact spot, how many strokes does the average golfer at your level need to hole out?

That benchmark is built from distance and lie. A shot from 150 yards in the fairway has an expected score. A shot from 150 yards in the rough has a slightly higher one. Putt from 20 feet, and there’s an expected number of putts to finish. None of those benchmark values come from a sensor. They come from a baseline table built on millions of shots.

A GPS sensor’s only job is to capture distance and lie automatically. golfity skips the middleman and lets you enter the same two numbers directly.

How golfity calculates strokes gained without GPS sensors

When you track a round shot by shot, each shot needs two pieces of information:

• Distance to the hole — yards for full shots, feet for putts
• Lie — tee, fairway, rough, sand, or green

golfity takes the spot you were in before the shot, looks up the expected strokes from that spot, then does the same for where the ball ended up. The difference, minus the one stroke you took, is your strokes gained for that shot.

Here’s a real example on a par 4:

• Tee shot: 420 yards, tee → ball finishes 160 yards out in the fairway
• Approach: 160 yards, fairway → ball finishes 18 feet from the hole
• First putt: 18 feet, green → ball finishes 2 feet away
• Second putt: 2 feet, green → holed

The approach from 160 in the fairway has an expected score of roughly 2.98 strokes to hole out. You hit it to 18 feet, which has an expected 1.78 strokes left. You used one shot to move from 2.98 to 1.78, so you gained 2.98 − 1.78 − 1 = +0.20 strokes on that approach. No sensor measured a single yard of that. You entered the distances, and the strokes gained calculator handled the arithmetic.

Mark Broadie’s baselines do the heavy lifting

The expected-strokes values come from the research of Mark Broadie, the Columbia professor who created strokes gained and wrote Every Shot Counts. His baseline tables map nearly every distance-and-lie combination to an expected score.

golfity uses these baselines as the reference point for every shot you enter. Because the model is doing the comparison, the only thing the system needs from you is an honest distance and lie. That’s the same input a $200 sensor set collects automatically; you’re just supplying it yourself.

How accurate is manual entry?

The common worry is that eyeballing a distance is less precise than GPS. In practice, strokes gained is forgiving. Being off by five yards on a 160-yard approach changes the expected score by a couple hundredths of a stroke. Across a full round, those small errors wash out, and you can read the same category breakdowns—off-the-tee, approach, around-the-green, and putting—that the sensor crowd pays for.

What matters far more is consistency and volume. We cover how much data you need in how many rounds you need for accurate stats, and most golfers reach reliable numbers after a handful of tracked rounds.

Start tracking without buying hardware

You already know roughly how far you are from the hole on every shot—that’s all golfity needs.

1. Sign up for golfity and add your course
2. Choose shot-by-shot tracking for a new round
3. Enter the distance and lie for each shot (add the club for club-by-club stats)
4. Review your strokes gained breakdown to see where you gained and lost

Same Mark Broadie math, same category-by-category insight, none of the hardware. You can even enter shots on a paper scorecard during the round and type them in afterward.