Find the exact date and time you turn 1 billion seconds, 10,000 days, or 1 million hours old — and every milestone in between.
Based on each planet's orbital period around the Sun. Earth = 365.25 days.
Notable accomplishments by historic figures, sorted by the age they achieved them.
Based on typical maximum lifespans. Sorted from shortest to longest.
Find dates when two people hit round-number milestones within 30 days of each other — great for couples, siblings, or friends.
Your age in seconds is the exact number of seconds elapsed since your date and time of birth. A person in their early 30s is roughly 1 billion seconds old. Enter your date of birth above for a live, updating count of your exact age in seconds, minutes, hours, days, weeks, months, years, and heartbeats.
One billion seconds equals approximately 31 years and 8 months. Enter your date and time of birth above to find your exact 1-billion-second birthday, complete with a live countdown or the date it already occurred.
The calculator shows your exact age in days, updated every second. Milestones include 10,000 days (about 27.4 years), 5,000 days (about 13.7 years), and 25,000 days (about 68.5 years).
Pi (π ≈ 3.14159…) billion seconds equals approximately 99.5 years. The golden ratio (φ ≈ 1.618…) billion seconds is around 51.3 years. Find both in the Seconds tab of the milestone grid.
A Martian year is 686.97 Earth days — about 1.88 times longer than an Earth year. A 35-year-old on Earth is about 18.6 Mars years old. The Planet Ages section shows your current age on all seven planets, plus a countdown to your next birthday on each one.
Precision depends on your exact birth time and timezone. Without a time, this calculator defaults to noon (12:00:00 PM) and clearly marks the result as approximate. All arithmetic uses the Luxon library for full timezone-aware, leap-year-correct calculations.