The Rules of Golf recommend that you put an identifying mark on the ball you play (Rule 6.3a). There is no penalty for leaving it blank, but a mark is how you prove a ball is yours (Rule 7.2), and playing the wrong ball costs two strokes in stroke play (Rule 6.3c). A pen line and two dots takes ten seconds.
The RulesMarking, identifying and wrong balls
| Situation | What the Rules say | Penalty |
|---|---|---|
| Marking the ball you will play | Rule 6.3a: the player should put an identifying mark on the ball to be played. | No penalty stated |
| Identifying a ball you saw stop | Rule 7.2: a ball at rest is yours if you, or anyone, saw it come to rest where it is known to be your ball. | None |
| Identifying by your mark | Rule 7.2: seeing your identifying mark on the ball counts, unless an identical ball with an identical mark is also found in the same area. | None |
| Identifying by brand, model, number and condition | Rule 7.2: a ball with the same brand, model, number and condition, found where your ball is expected, counts. It does not count if an identical ball is also there and no one can tell which is yours. | None |
| Lifting a ball to identify it | Rule 7.3: if the ball might be yours but cannot be identified as it lies, you may lift it, including by rotating it. Mark the spot first. Clean it only as much as needed to identify it (the putting green is the exception). Replace it on the original spot. | None if you follow those steps |
| Lifting when it was not reasonably necessary, not marking the spot, or cleaning more than allowed | Rule 7.3: each one is a breach. A lift on the putting green under Rule 13.1b is the exception to the first. | One penalty stroke |
| Playing a substituted ball when you were not allowed to substitute | Rule 6.3b: the original ball is no longer in play, even if it is sitting on the course. You play out the hole with the substituted ball. | One penalty stroke |
| Hitting a wrong ball, stroke play | Rule 6.3c: a player must not make a stroke at a wrong ball. Go back to your original ball and play it as it lies or take relief. The wrong-ball stroke and any strokes before the fix do not count. | Two penalty strokes. Disqualification if not corrected before you start another hole, or before you return your card on the last hole |
| Hitting a wrong ball, match play | Rule 6.3c: general penalty. If both players play each other's balls and no one knows who hit first, there is no penalty and the hole is played out with the balls swapped. | Loss of hole |
| Hitting a wrong ball that is moving in water in a penalty area or in temporary water | Rule 6.3c: the stroke does not count. Play your own ball from its original spot or take relief. | None |
Source: The R&A, Rules of Golf, Rules 6 and 7 (randa.org).
Here is why the mark matters. Two balls of the same brand, model and number lying in the same patch of rough look identical, and if nobody can tell which is yours, a lookalike proves nothing. A mark only your ball carries settles it.
How toHow to mark your ball
One example mark: a line and two dots, drawn so they are easy to see from a few feet away.
Use a fine-tip permanent marker. It is quick to draw with and the mark lasts through a round.
Pick a mark that is yours. A line, two dots, a small cross, your initials or a short row of dashes all work. The aim is something your playing partners are not also using. If you all play the same model and number, a simple line is not enough on its own.
Make it big enough to read from a few feet away. A mark you can only see with the ball in your hand does not help when the ball is lying in the rough. A line that goes right around the ball, or a mark on both sides, works well.
Mark it before the round. Rule 6.3a is about the ball you will play, so do it at the tee or in the car park, not after a search starts. Carry the marker in your pocket and mark the next ball the same way.
Mark a provisional ball differently. If you hit a provisional, a different number or a second mark lets you tell it from the original. Our lost ball and provisional ball guide covers when you can play one.
The numberThe number printed on the ball
Most golf balls carry a single-digit number printed by the maker next to the logo. Most makers print 1, 2, 3 or 4, and some go up to 8. Custom orders can carry other numbers, including two digits.
The number is there mainly so players in a group can tell their balls apart, including when they all play the same model. It counts as part of what makes a ball identical under Rule 7.2 (brand, model, number and condition), but it is not a mark you put on yourself. If you want to be sure, add your own mark on top of it.
Watch forCommon mistakes
Relying on the number alone. Two players on the same model and number can end up with identical balls in the same area. Add a mark.
Using the same mark as your playing partner. A line is common. Ask what others use, or add dots or initials.
Using a mark that wears off. A scuffed or faded line leaves you with a ball that looks like every other ball. Check it after a few holes and redraw if needed.
Lifting a ball before marking the spot. Under Rule 7.3, you mark the spot first. Lifting without marking it is a one-stroke penalty.
Wiping the ball clean. Away from the putting green, clean the ball only as much as you need to identify it. More than that is a one-stroke penalty.
Hitting before you check. If you are not sure the ball is yours, check first. A stroke at a wrong ball in stroke play is two penalty strokes, plus the stroke wasted.
For other common penalties, see the golf penalty chart.
FAQQuick answers
Do I have to mark my golf ball?
The Rules say you should (Rule 6.3a), and they state no penalty for not doing it. A mark is the clearest way to show a ball is yours under Rule 7.2.
What happens if I hit the wrong ball?
In stroke play it is two penalty strokes. You go back and play your original ball, and the wrong-ball stroke does not count. In match play you lose the hole. Rule 6.3c has the details.
Can I pick up a ball to check if it is mine?
Yes, if it might be yours and you cannot tell as it lies (Rule 7.3). Mark the spot first, clean the ball only as much as you need to see the mark, and put it back on the original spot. On the putting green you can clean the ball fully.
What do the numbers on a golf ball mean?
The number is mainly there so players can tell their balls apart. Most makers print 1, 2, 3 or 4, and some print up to 8.
What should I use to mark my ball?
A fine-tip permanent marker. The Rules only ask for an identifying mark, so a line, dots, a cross or your initials all work.
What if my playing partner has the same ball and the same mark?
Rule 7.2 says a mark does not count as proof if an identical ball with an identical mark is found in the same area. Change your mark before you tee off so that does not happen.