📅 Age Calculator by Date of Birth
Accurate age calculator by date of birth | Calculate exact age in years, months and days | Free online age calculator tool
Calculate Your Exact Age
What is Age Calculator by Date of Birth?
An age calculator by date of birth is a digital tool that helps determine a person's exact age in years, months, and days. This essential utility finds applications in medical fields, education systems, legal documentation, and personal record-keeping. By simply entering birth date details, users can instantly calculate chronological age, verify eligibility for services, track developmental milestones, and manage age-related requirements. Our precise calculator considers leap years and month variations for 100% accurate results.
Age Calculation Formula
The age calculation formula compares current date with birth date:
Age = Current Date - Birth Date
If birth month/day hasn't occurred yet this year, subtract 1 year
How to Use
- Enter birth day (1-31)
- Input birth month (1-12)
- Provide birth year (1900-currrent year)
- Click "Calculate Age"
Calculation Process
| Step | Action |
|---|---|
| 1 | Get current date |
| 2 | Compare with birth date |
| 3 | Calculate year difference |
| 4 | Adjust for uncompleted month |
| 5 | Calculate remaining months/days |
Advantages/Disadvantages
Advantages:
- Instant age verification for official documents
- Accurate medical age calculations
- Simplifies school admissions processes
- Automates age-related eligibility checks
- Saves time in manual calculations
Disadvantages:
- Dependent on accurate date input
- Doesn't account for time zones
- Can't calculate future dates
- Limited to Gregorian calendar
- No daylight saving adjustment
FAQs
How accurate is this age calculator?
Our calculator provides 100% accurate results by accounting for leap years (including century years) and varying month lengths. It uses JavaScript's Date object for real-time current date comparison, ensuring precision down to the day.
Can I calculate age for future dates?
No, this calculator only works for past dates. Entering future birth dates will show negative values or error messages as age cannot be predicted.
Does it work for historical dates?
Yes, the calculator works for any valid date from 1900 to current year. It can calculate ages up to 124 years accurately.
How are leap years handled?
February 29 births are automatically adjusted to March 1 in non-leap years for accurate calculations. The system recognizes all leap year rules including century year exceptions.
Can I calculate age in months?
Yes, results display age in years plus remaining months and days. For infants, manual month calculation is possible using the days result.