Other

Age Calculator

Calculate exact age, total days lived, and next birthday from two dates.

Inputs

Defaults are prefilled so the result is visible immediately.

Birth date

Age on

Results

Results update as the calculator inputs change.

Age

35 years, 11 months, 21 days

Total days

13,140

Total weeks

1,877.1

Next birthday

May 15, 2026

Days until birthday

Formula and Assumptions

Calendar age is computed by comparing year, month, and day boundaries between birth date and as-of date.

The calendar age accounts for month and day boundaries.

Total days uses date-to-date elapsed days.

Reference Upgrade

Built from the Calculator.net model, with added context.

Live validation and instant result updates instead of a submit-only workflow.

Multiple decision metrics are shown together, not only the primary answer.

Formula notes and assumptions are visible on the page so the math is easier to audit.

Reference Model

Modeled after the input style and primary output on Calculator.net's Age Calculator.

The page keeps the math in one place and exposes the assumptions beside the result.

Default inputs: birthDate=1990-05-15, asOfDate=2026-05-06