Your cell number comes first, plus a backup number. Add the dog’s name only if you want, and useful notes such as needs medication.
The tag that gets a dog home
Put your cell phone number on a dog ID tag first, and add a second number if there is room. That is the only essential detail. A tag is the fastest way home for a dog, since anyone can read it without a scanner or a trip to a vet. In a national ASPCA survey, 15 percent of the recovered dogs came back through a tag or microchip. Then consider a few more words if your tag has room: Microchipped, Needs meds or Reward. Keep the text big and short so it can be read at arm’s length.
Phone numbers first
Use a cell number that you answer, because a person who has just found a dog wants to speak to someone right away. Do not use a landline that nobody picks up, or a work number after hours. A second number for a partner, family member or friend is very useful in case your phone is off or you are traveling. Check your tag each time you change your number, since an old number on a tag is no use. Set your voicemail to a clear greeting that gives a second way to reach you.
Should the dog’s name go on it?
This is a judgment call. A name can help a finder calm a dog, and many people find it useful. Some owners leave it off, worrying that a stranger could use it to call the dog away. No evidence we know of settles this. If you leave the name off, use the space for a second phone number. Either way, the phone number is what matters most, so do not shrink it so that the name will fit.
What about your address?
An address can help if your dog is found in your neighborhood and your phone is off, since a neighbor can walk the dog right back. It also gives strangers your home location, which some owners would rather avoid. A middle option is your street name or town. The town is especially useful for travelers and on holiday: a dog found in a new area with a tag that gives a distant town tells the finder it may be away from home. Whatever you choose, there should be a phone number on the tag.
Useful extras
If your dog needs daily medicine, say so: Needs meds. This can prompt quicker action, and it can make someone less likely to keep a found dog. Deaf or Blind tells a finder how to approach. Microchipped reminds them to get a scan. Some owners add Reward. If a dog has a condition that a vet must know about, a tag with a short note and your phone number is more use than a paragraph, since a finder only has to call you. Do not put on anything you would rather keep private.
Choosing the type of tag
Engraved metal tags last longer than printed ones, and deep engraving wears less than a thin surface print. Tags on split rings can fall off, so check them regularly. A slide-on tag or a collar with your number stitched or engraved on it is harder to lose and does not jingle. Cats need a breakaway collar, and a vet can advise on safe options. Check every few months that you can still read each digit. A worn tag does nothing, and replacing one costs little compared to a lost dog search.
Rabies and license tags are not a substitute
Rabies tags and city or county license tags are useful, and they can be traced, but only through an office, usually during working hours. If your dog is found at night, the finder will have no easy way to reach you. In the Dayton, Ohio study of lost dogs, license tags helped with recovery, which is a good reason to keep them on the collar. But add your own ID tag with a phone number too. Each one does a different job, and the extra tag means that a finder can call you directly.
Keep it on the dog
A tag is only useful when your dog is wearing it. Many dogs are lost during baths, grooming or play, or when a collar has been taken off at night. Keep the collar on whenever a door might open, especially when moving house, during holidays and when workers or guests are around. Check that the collar fits: you should be able to slip two fingers under it. A collar that slides over the ears can come off in a panic, so check it after any weight change, and use a chip as your backup.
Sources
Weiss, Slater and Lord, Animals, 2012: pmc.ncbi.nlm.nih.gov/articles/PMC4494319. Lost-pet recovery in Dayton, Ohio: news.osu.edu/lost-dogs-found-more-often-than-lost-cats-study-suggests.