Vaccine Schedule Calculator

The real ACIP-recommended schedule gives each dose a window rather than one exact age -- for example, the fourth DTaP dose is recommended anywhere from 15 to 18 months. This calculator picks one representative age within each real window to keep the due/overdue comparison simple, so treat the result as an approximation rather than the precise ACIP window itself.

This calculator flags a dose as due now if its representative age has passed within about the last two months, and overdue if it's been more than two months past that age. The distinction is meant to separate a dose that's simply ready to be given at a routine visit from one that likely needs a dedicated catch-up appointment.

Neither. Completion percentage counts how many doses have been received out of the total recommended series across all four vaccines, regardless of your child's current age or whether those doses were given exactly on schedule -- a child who received every dose but consistently late can still show 100% completion once all doses are in. It also covers only the four vaccine series this calculator tracks (DTaP, IPV, MMR, and Hepatitis B), not the full ACIP-recommended childhood schedule, which includes roughly eleven routine series; Hib, PCV (pneumococcal), rotavirus, varicella, Hepatitis A, influenza, and COVID-19 doses are not tracked at all, so 100% here means only that these four tracked series are done -- check with your pediatrician for full ACIP compliance.

A value of 0 is reserved for a genuinely complete tracked schedule. If a child is significantly under-immunized and past this calculator's oldest representative dose age, every remaining dose in the tracked series is already due now or overdue, so there's nothing scheduled in the future -- but that's very different from being fully vaccinated. In that situation, Next Due at Age reports the child's current age (since every outstanding dose is already due right now) rather than the misleading age of 0.

Not precisely. Catch-up immunization follows its own set of ACIP rules with minimum intervals between doses that can differ from the routine schedule this calculator simplifies. For a child who started late or missed doses, use this as a general orientation and follow your pediatrician's specific catch-up schedule.