Age Calculator
Calculate exact age from date of birth to today (or any custom date).
Advanced — Local timezone · Weeks shown · Birthday shown
What is Age Calculator?
An age calculator computes your exact age in years, months, and days from your date of birth to a target date (default: today). It accounts for varying month lengths and leap years, so the result is precise down to the day. ToolCrux's free tool runs entirely in your browser with instant results and no data sent to any server.
Real-world use cases include finding your exact age for forms, calculating a child's age for school enrollment, determining age as of a past or future date for legal or planning purposes, and tracking milestones like total days lived or weeks lived. The next-birthday countdown is handy for reminders and celebrations.
How to Use Age Calculator
- Enter your date of birth in the first field using the date picker.
- The "As of date" defaults to today. Change it to calculate age as of another date (past or future).
- Click Calculate Age or press Ctrl+Enter. Results appear instantly.
- View the stat grid: Years, Months, Days, Weeks Lived, Total Days, and Birthday In (days until next birthday).
- Use Copy to copy the summary, Use Sample for a demo, or Clear to reset.
Tips & Best Practices
Open Advanced to switch between local timezone and UTC, or to hide weeks and birthday countdown. Use Ctrl+Shift+C to copy and Esc to clear. February 29 birth dates are supported and handled correctly across leap years. The as-of date must be after your date of birth. For timestamp-based date math, try our Unix timestamp converter.
When to Use This Tool
Use the age calculator for forms, school enrollment, legal documents, milestone tracking, or birthday planning. Pair it with the percentage calculator for growth or share calculations, or the Unix timestamp converter for epoch-based date work.
Frequently Asked Questions
What is an age calculator?
An age calculator computes your exact age in years, months, and days from your date of birth to a target date (default: today). It also shows total days lived. ToolCrux's calculator runs in your browser.
How do I calculate my age?
Enter your date of birth in the first field. The "As of date" defaults to today. Click Calculate Age to see years, months, days, and total days lived.
Can I calculate age as of a past or future date?
Yes. Change the "As of date" to any date after your birth. The calculator will show age as of that date. The as-of date must be after your date of birth.
How accurate is the age calculation?
The calculator accounts for varying month lengths and leap years. It gives exact years, months, and days between the two dates. For date math, try our percentage calculator for other computations.
Is the age calculator free and private?
Yes. The ToolCrux age calculator is free, requires no signup, and runs entirely in your browser. Your dates are never sent to any server.
How do I find out how many days until my next birthday?
Enter your date of birth and click Calculate Age. The "Birthday In" stat shows exactly how many days remain until your next birthday from today (or any as-of date you set).
How does the age calculator handle leap years?
The calculator uses JavaScript's native Date object, which correctly accounts for leap years (including century rules). February 29 is treated as a valid birth date, and ages are computed accurately across leap years. For timestamp-based date math, try our Unix timestamp converter.