Supported Features
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VoiceOver
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Larger Text
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Dark Interface
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Sufficient Contrast
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Reduced Motion
Plumb Bob: Golf Green Reader
Putting line, break & slope
Free · In‑App Purchases
Walk from ball to cup and see your putt line, aim point and break on the grass. Measure green speed free, then try Pro free for a week. Works offline, no account.
Plumb Bob turns your iPhone into a green reader.
Golfers have plumb-bobbed putts with a putter shaft for a hundred years. Plumb Bob gives you a truly vertical line from the phone's sensors, maps the slope of the whole putt as you walk from your ball to the cup, and rolls test putts over it at the green's speed. The line, the aim spot and the break appear on the grass in about twenty seconds.
BALL. HOLE. PLUMB.
• Mark your ball, walk your line to the hole and aim at the cup
• Stand behind the ball and hold the phone up: the plumb line shows which way it breaks
• See the putting line on the green, where to aim, how much it breaks and how long it plays
GREEN SPEED FROM ONE ROLL
• Roll any ball 8–15 ft and Plumb Bob measures the Stimp
• Roll one back the other way to cancel out slope
• Or pick Slow, Medium, Fast or Tour
YOUR PUTTING SCORE
• Play a round and every putt you read is scored against a tour putter (strokes gained)
• Make percentages by distance and by slope, and what to work on
• A recap card for every round, ready to share
BUILT FOR iPHONE
• Haptics you feel as the ball drops
• Your round on the Lock Screen and in the Dynamic Island
• Siri, the Action Button and Control Center: straight into a read
• Home and Lock Screen widgets
• Full VoiceOver and Dynamic Type support
PRIVATE BY DESIGN
No account. Everything is worked out on your phone, it works offline, and it collects no data.
Try the demo green without going to the course. Measuring green speed is always free. Plumb Bob Pro unlocks unlimited reads, rounds with strokes gained, and stats, with a free week to start.
Terms of use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Try Plumb Bob Pro free for a week straight after the intro, or carry on with your three free reads. Plus small improvements.
The developer, KATHERINE YVONNE PATTON, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Purchases
- Usage Data
The developer indicated that this app supports the following accessibility features. Learn More
Information
- Seller
- KATHERINE YVONNE PATTON
- Size
- 18.4 MB
- Category
- Sports
- Compatibility
Requires iOS 18.0 or later.
- iPhone
Requires iOS 18.0 or later. - iPad
Requires iPadOS 18.0 or later. - Apple Watch
Requires watchOS 10.0 or later.
- iPhone
- Languages
English and 7 more
- English, French, German, Japanese, Korean, Simplified Chinese, Spanish, Swedish
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Plumb Bob Pro (Annual) $59.99
- Plumb Bob Pro (Monthly) $9.99
- Copyright
- © 2026 Katherine Yvonne Patton