The age calculator gives you a precise breakdown of your age — not just years, but months, weeks, days, and hours. Whether you need your exact age for a legal document, want to know how many days until your next birthday, or are curious what age you'll be at a future date, this free tool handles it instantly. It accounts for leap years, varying month lengths, and all edge cases.
How the Age Calculator Works
Enter your birth date and the target date (defaulting to today). The calculator finds the number of completed years, then the remaining completed months, then the remaining days. For total counts (days, weeks, hours), it computes the raw millisecond difference between the two dates and converts — ensuring leap years and varying month lengths are handled precisely. The zodiac sign is determined by your birth month and day against the standard Western zodiac boundaries.
3 Real-World Examples
Born December 15, 1990. As of May 3, 2026, that's 35 years, 4 months, 18 days — or 12,922 days — or 1,846 weeks. Exact day counts matter for insurance, legal documents, and some financial products.
Born February 28, 2025. As of May 3, 2026: 14 months and 3 days old (not "1 year" — pediatric development milestones use months until age 2).
When will someone born on July 4, 1985 turn 65 (Social Security full retirement age)? Enter birth date + target date July 4, 2050 → find exactly when they become eligible for full benefits.
Tips
- Use the "Calculate Age On" field with a future date to plan for milestones like retirement eligibility or a child's school enrollment cutoff.
- For legal documents, always use your official birth certificate date — not a remembered or estimated one.
- Parents of infants: track age in months and days, not just years, to align with pediatric growth chart milestones.
- Combine with the Date Difference calculator when you need the interval between two arbitrary dates that aren't birth-related.
Understanding Date Arithmetic
Age calculation seems simple but involves subtleties: months have 28–31 days, leap years add a day in February, and the question of "how old am I" depends on whether today has passed your birthday this year. The Gregorian calendar (in use worldwide since 1582) is the standard reference. For historical dates before 1582, the Julian calendar was used — a small discrepancy that only matters for genealogical or historical research. Our calculator uses the Gregorian calendar throughout.