When do puppies start their vaccines?

Core puppy vaccination typically begins at 6 to 8 weeks of age with the first DHPP dose, then repeats every 3 to 4 weeks until about 16 weeks. Rabies is usually given once at 12 to 16 weeks depending on local law.

What is the kitten core series?

Kittens receive the FVRCP combination vaccine starting around 6 to 8 weeks, boostered every 3 to 4 weeks through about 16 weeks. Rabies is given once around 12 to 16 weeks, and FeLV is recommended for kittens with outdoor exposure.

Why are boosters spaced 3 to 4 weeks apart?

Maternal antibodies passed in milk can neutralise a vaccine, and they fade at different ages in different animals. Repeating the dose every few weeks ensures at least one shot lands after maternal immunity has waned, producing lasting protection.

When is the first annual booster?

After the puppy or kitten series finishes around 16 weeks, a booster is given one year later. This tool schedules that first annual booster, after which most cores move to a one to three year cycle set by your vet.

Is this a substitute for veterinary advice?

No. This is a planning aid using standard age windows. Rabies law, FeLV and lifestyle vaccines, and any health concerns must be decided with your veterinarian, who may shift dates for your pet and jurisdiction.

What is the Pet Vaccination Schedule Calculator?

Enter your pet's birth date and species to generate a dated core vaccination schedule — DHPP and rabies for puppies, FVRCP and rabies for kittens — with the standard 3-4 week booster intervals and the first annual booster. It runs free in your browser on Gera Tools, with nothing uploaded.

Pet Vaccination Schedule Calculator

Name: Pet Vaccination Schedule Calculator
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

A puppy or kitten’s core vaccine series is timed by age in weeks, with doses repeated every few weeks until maternal antibodies have faded. This calculator turns your pet’s birth date into a dated schedule of those core shots plus the first annual booster.

How it works

The schedule anchors each dose to a target age in weeks and adds it to the birth date:

DHPP / FVRCP dose 1  →  ~8 weeks
DHPP / FVRCP dose 2  →  ~12 weeks  (3-4 week interval)
DHPP / FVRCP dose 3  →  ~16 weeks
Rabies               →  ~14 weeks  (single juvenile dose)
First annual booster →  dose 3 date + 52 weeks

Dogs receive DHPP (distemper, hepatitis/adenovirus, parainfluenza, parvovirus); cats receive FVRCP (feline viral rhinotracheitis, calicivirus, panleukopenia). Each date is computed as birth date plus the target number of weeks.

Why maternal antibodies make repeated doses necessary

Newborn puppies and kittens receive passive immunity through their mother’s colostrum (first milk). These maternal antibodies protect the pup or kitten in early life but also neutralise any vaccine given during that window — the vaccine cannot trigger the animal’s own immune response while maternal antibodies are still circulating. The problem is that maternal antibody levels fall at different rates in different animals, so there is no single safe age at which one dose will reliably work for every individual.

The solution is a series of doses at intervals. Each dose is an attempt to catch the animal in the window when maternal antibodies have fallen enough to allow the vaccine to take. By the final dose at 16 weeks, virtually all animals have low enough maternal immunity for the vaccine to produce lasting protection. Skipping doses or spacing them too far apart risks an animal spending weeks in the danger zone — old maternal immunity gone, new vaccine immunity not yet established.

What the core vaccines protect against

DHPP (dogs) covers:

Distemper: a severe, often fatal viral disease affecting the nervous system and respiratory tract
Hepatitis/Adenovirus-2 (H): liver disease (adenovirus-1) and infectious tracheobronchitis; the A2 antigen cross-protects against both
Parainfluenza (P): one component of kennel cough
Parvovirus (P): a highly contagious and frequently fatal gastrointestinal disease, especially in young unvaccinated dogs

FVRCP (cats) covers:

Feline Viral Rhinotracheitis (herpesvirus-1): upper respiratory disease
Calicivirus: upper respiratory and oral disease
Panleukopenia (feline parvovirus): the feline equivalent of canine parvovirus, often fatal in kittens

Rabies is legally required in most jurisdictions for both species. It is a single juvenile dose given between 12 and 16 weeks (timing varies by local law), then a booster one year later, followed by three-year boosters in most regions.

Lifestyle vaccines to discuss with your vet

Beyond core vaccines, your vet may recommend additional vaccines based on your pet’s lifestyle:

Dogs: Bordetella (kennel cough) for dogs in kennels or dog parks; Leptospirosis for dogs in wet or wildlife-heavy environments; Lyme for tick-exposure areas.
Cats: Feline Leukaemia Virus (FeLV) for kittens and outdoor cats — considered core for kittens by many veterinary bodies.

Notes and tips

Bring the dated list to your first appointment so your vet can adjust for local rabies law, lifestyle vaccines, and your pet’s individual health. Do not let more than about four weeks lapse between boosters in the puppy or kitten series — a long gap can mean restarting doses to guarantee protection after maternal antibodies fade. This tool is a planning aid, not a substitute for veterinary advice.