Pet Vaccine Schedule Calculator

General guidance based on typical core vaccine protocols. Consult a veterinarian for the exact schedule — not professional veterinary advice.

Tracking Where a Pet Sits in the Core Vaccine Series

Puppy and kitten vaccination isn't a single visit — it's a series of boosters spaced a few weeks apart, because maternal antibodies can interfere with early doses and the series has to continue until that interference has reliably faded. This calculator estimates where an animal falls in that series, or when the next annual booster is likely due, based on current age alone.

The Formula

Standard core-series protocol: Boosters given every 3 weeks, starting at 6 weeks of age, continuing until at least 16 weeks of age Remaining Boosters = ceil((16 − Current Age in Weeks) ÷ 3)

Worked Examples

Vaccine timing at sample ages
Current ageResult
4 weeksFirst vaccine due in about 2 weeks
6 weeks4 booster(s) remaining, next due in 3 weeks
10 weeks2 booster(s) remaining, next due in 3 weeks
20 weeks (past series)Next annual booster due in about 48 weeks

Once past the 16-week core series window, the calculator assumes the series is complete and estimates the next annual (or triennial, for some vaccines) booster on a 52-week cycle from the end of the series.

Where This Calculation Matters

  • New pet owners — getting a rough sense of how many more puppy or kitten visits to expect before the core series wraps up.
  • Adopted or rescue animals — estimating a vaccine timeline when exact prior vaccination dates aren't available, based on current age alone.
  • Planning around travel or boarding — checking whether a pet's vaccine series will be current by a target date.
Note: This reflects a general core-series protocol and does not account for specific vaccines, regional disease risk, or an individual pet's health history. Consult a veterinarian to confirm the exact vaccines and schedule appropriate for your pet — this is not professional veterinary advice.

How to Use This Calculator

  1. Select the Species (dog or cat).
  2. Enter the pet's Current Age in weeks.
  3. Select Calculate to see where the pet stands in the vaccine schedule.

Related Calculations

Track physical development alongside the vaccine schedule with the Pet Weight Growth Calculator, or estimate the cost of an upcoming visit with the Vet Bill Estimate Calculator.