New puppy timeline: every date from birth to one year

At or after 16 weeks of age — and 18–20 weeks is preferred in areas with high parvo or distemper risk. This matters because antibodies from mom can block the vaccine and may persist 13–15 weeks or longer, so a series finishing at 15 weeks can leave a puppy unprotected. The number of doses is whatever it takes to reach that 16-week endpoint at 2–4 week intervals.

Yes — and AVSAB says you should. The prime socialization window is the first three months of life, which closes about three weeks before the vaccine series even finishes. Their position is that socialization should be the standard of care before full vaccination, because behavioral problems, not infectious disease, are the leading cause of death in dogs under three. Puppies can start classes at 7–8 weeks with one set of vaccines given at least 7 days prior plus a first deworming.

Four in the first four months, spaced two to four weeks apart, not a separate trip per vaccine. A typical schedule: 6 weeks (first DAP plus deworming, usually at the breeder), 8 weeks (second DAP, the first full exam with you, and starting heartworm and flea/tick prevention), 12 weeks (third DAP and first leptospirosis), and 16 weeks (the final DAP and second leptospirosis). Rabies is labeled for 3 months and older — about a week after the 12-week visit — so it's either a quick extra stop around 13 weeks or folded into the 16-week visit, as your state's law allows. Vaccines are routinely given together — many practices use a 7-in-1 shot that combines DHPP with leptospirosis, and AAHA notes there's no good evidence that giving several at once weakens the response to any of them.

Not any more. AAHA reclassified leptospirosis as a CORE vaccine — recommended for all dogs regardless of lifestyle — in its 2024 guideline update. It was previously risk-based, so older advice and many websites still describe it as optional. Two doses 2–4 weeks apart, the first no earlier than 12 weeks of age, then annual boosters.

As early as 7–8 weeks, provided it's had at least one set of vaccines 7 or more days before the first class and a first deworming, per AVSAB. Choose classes on cleanable surfaces and avoid dog parks or other high-traffic areas where vaccination status is unknown.

It depends on projected adult size, and for large females the guidelines deliberately don't give one answer. AAHA suggests about 6 months for small breeds (or before the first heat for females), and waiting until growth stops — usually 9–15 months — for large-breed males. For large-breed females the recommended range is 5–15 months, weighing earlier spay against orthopedic and cancer risks. This is a genuine your-dog-your-vet decision.

No later than 8 weeks of age, per the American Heartworm Society — some products are labeled from 4 weeks. If you start after 8 weeks, the puppy needs a heartworm test 6 months after that first dose. First routine testing isn't justified before about 7 months of age.

CAPC recommends starting at 2 weeks of age and repeating every 2 weeks until regular broad-spectrum monthly parasite control begins, plus fecal testing at least four times during the first year. The first one or two treatments happen at the breeder or shelter before most puppies go home.

Eight weeks is the standard minimum (Cornell), with Merck putting the absolute floor around 7½ weeks. Puppies taken earlier are more likely to show fear, anxiety, resource guarding and reactivity. Some states set a legal minimum, and toy breeds are often held to 10–12 weeks.