Age nearest birthday is the full expression of the age-nearest method used by some insurers to determine insurance age by rounding to the closest birthday rather than using the last actual birthday. Typically, if the application date is within six months after the last birthday, the applicant is considered that age; if it is six months or more past, the applicant is considered to have reached the next age for premium purposes. This convention can result in earlier age increases than clients expect and may slightly disadvantage those whose birthdays fall soon after their application dates. Age nearest birthday is contrasted with age last birthday and age exact methods, and is one of the key age basis decisions carriers make in pricing.

Advisors referencing age nearest birthday often do so when clients question why their insurance age is higher than their current age. They clarify that the carrier uses a rounding convention and that applying before or after the six-month point can change the age used for pricing. In practice, advisors may select carriers with more favorable age bases or adjust application timing to avoid being rounded up. Case design spreadsheets commonly annotate which products use age nearest, so that side-by-side comparisons are fair and transparent. Understanding age nearest birthday allows advisors to manage expectations, avoid pricing surprises, and strategically align carrier selection and timing with client objectives and budgets.