Free Date & Age Calculators Online
Calculate age, date differences, and find future or past dates.
Dates and durations come up in surprisingly many contexts — legal documents, project planning, milestone tracking, age verification, and personal curiosity. Our three date-focused calculators cover every common scenario. The Age Calculator determines your exact age in years, months, and days from your birthdate. The Date Calculator adds or subtracts days, weeks, months, or years from any date. The Date Difference Calculator finds the precise duration between any two dates in multiple units. Together, these tools answer every "how long" and "when" question you can think of.
Date & Age Calculators Calculators
Time-Based Calculations Made Simple
Calendar math is deceptively tricky. Months have different lengths, leap years add a day every four years (with century exceptions), and varying conventions complicate edge cases. Our calculators handle all of these so you get correct results every time.
Age Calculator
Enter your birthdate and get your exact age in years, months, and days — accounting for leap years and varying month lengths. Also shows total months, weeks, and days for contexts like pediatric milestones or insurance calculations.
Date Calculator
Start from any date and add or subtract days, weeks, months, or years. Find deadlines, plan events, calculate due dates, or determine contract expirations. Handles month-end edge cases and leap year transitions correctly.
Date Difference Calculator
Enter two dates to find the exact duration in years, months, days, weeks, hours, and minutes. Perfect for project durations, warranty periods, and historical timelines.
Common Uses
- Legal & HR — Age verification, employment duration, contract periods.
- Project Management — Sprint durations, milestone spacing, deadline calculations.
- Personal — Birthday countdowns, anniversary tracking, vacation planning.
- Medical — Gestational age, treatment duration, appointment scheduling.
Frequently Asked Questions
The calculator uses the Gregorian calendar rules: a year is a leap year if divisible by 4, except for century years unless also divisible by 400. So 2000 was a leap year, but 1900 was not. If your birthday is February 29, the calculator correctly determines your age on non-leap years by counting March 1 as the boundary date.
Our Date Calculator adds calendar days. For business days, you would need to account for weekends and holidays separately. As a rough conversion, 90 business days equals approximately 126 calendar days (90 ÷ 5 × 7). Enter 126 days in the Date Calculator for an approximate business-day deadline.
The difference usually comes down to how months of varying lengths are handled. Our Age Calculator follows the convention that a month boundary is crossed when the day-of-month is reached in the next month. For edge cases like the 31st of a month followed by a 30-day month, this convention avoids ambiguity by using the last day of the shorter month.
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