Start with 30 to 50 copies, then adjust by species and terrain. Here is how to split them and when to print more.
The short answer
Print 30 to 50 copies to start. That is enough to cover a half-mile radius around the place your pet was last seen, with posters at the main intersections and flyers for the nearest doors. For a cat, put most of them on the closest houses. For a dog, put more on roads and walking routes. Do not print hundreds on day one. Your first sightings often move the search, and a second batch aimed at the right streets will do more than a large first batch spread evenly across town.
Think in two formats
A full-page poster is for people passing by, and a flyer is for people you can hand one to. Twenty posters for corners and shop windows plus 30 half-page flyers for doors is a sensible opening split, and it only takes 35 sheets of paper, because a two-per-page flyer gives you two copies from each sheet. Fifty sheets of flyers makes a hundred. If you only have one printer and a limited amount of ink, use more flyers and fewer posters, then pay for a copy shop batch when you know where you need coverage.
How many for a lost cat
Lost cats tend to be close by. In a study of 1,210 missing cats, those found alive had a median distance of about 165 feet from where they escaped, or 50 meters, and three quarters were within about a third of a mile, or 500 meters. Indoor-only cats stayed closest, with a median of about 130 feet. So a cat flyer plan starts with every house on your block, the street behind you and the houses across from you. For most suburban streets, that may be 30 to 60 doors. A flyer at each door is worth more than ten posters across town.
How many for a lost dog
A dog can be on the move, so the numbers go toward visibility. Choose the intersections on the roads leading away from the last-seen spot, then add dog parks, trailheads and busy corners. Mission Viejo, California’s animal services advises expanding the search to at least seven blocks in all directions. A half-mile radius is a sensible start for most dogs, and you can extend it each day. In rural areas, where houses are far apart, fewer flyers cover more ground. Focus on crossroads, gas stations, feed stores and anyone who drives the same roads daily.
Rural, suburban and urban changes
In a dense city, poster life is shorter and sign rules are often stricter, so rely on building managers, doormen, shops and supers, and be ready to hand out more flyers per block. In a suburb, doors and corners are the core of the work. In the country, a dozen large posters at crossroads and businesses can matter more than a hundred sheets, and a yard sign at the end of a long driveway can do more than paper. In every case, count the actual places you can reach today, then print that number plus ten.
Why the second batch matters more
After the first day, you know more. You have had calls, you know which streets you finished and your neighbors have seen the first posters. That is the moment to print again, and to print with a purpose. If a sighting comes from two miles north, 20 flyers around that sighting are worth more than 50 more around your house. Update your master copy first, with the new area and date, and then print. Keep the earlier copies up unless the details are now wrong.
Keep a count
Note every place you have been, either on a paper map or a pinned phone map. Mark posters with a dot and finished streets with a line. Your list tells you what to refresh, what to take down later and where you have not yet been. It also makes it easier for friends to help. Give each helper a marked area, 15 to 20 flyers and tape, so two people do not cover the same street while another stays empty.
When to stop printing
Stop adding new copies when the phone goes quiet and everything in the area is still up, and turn to refreshing what you have and calling shelters. Keep going in smaller batches as long as you are searching. In the missing cat study, 34 percent of the cats had been found alive by day 7 and 50 percent by day 30, so a long search is not wasted effort. Replace faded posters, and change the wording to still missing with the original date so people know the search is active.
Sources
Huang et al., Animals, 2018: pmc.ncbi.nlm.nih.gov/articles/PMC5789300. City of Mission Viejo Animal Services: missionviejo.gov/departments/animal-services/lost-pet-help.