Age Calculator
Counts completed calendar years, then separately calculates elapsed calendar days.
Time & date10 free tools
Time & date
Make sense of dates, durations and days in between.
Most tool inputs are processed on your device.
10 of 10 tools
Date Difference
Elapsed days = (end UTC midnight − start UTC midnight) ÷ 86,400,000.
Time & dateAdd / Subtract Days
Adds a signed whole number of calendar days, rolling across month and year boundaries.
Time & dateBusiness Days Calculator
Counts Monday–Friday after the start date through the end date, subtracting unique supplied weekday holidays.
Time & dateWeek Number
ISO 8601 weeks start Monday.
Time & dateDay Of Year
January 1 is day 1.
Time & dateLeap Year Checker
A year is leap if divisible by 4, except centuries unless divisible by 400.
Time & dateCountdown Creator
Subtracts the current clock time from a target interpreted in the device’s timezone, updating each second.
Time & dateDuration Calculator
Total seconds = hours × 3600 + minutes × 60 + seconds.
Time & dateTime Duration Calculator
Subtracts start clock minutes from end clock minutes; optionally wraps an earlier end into the next day.
Time & dateA useful starting point
Dates become confusing when calendar rules, time zones and business conventions are mixed together. These tools state whether they use local device time, UTC-midnight calendar dates or a signed duration so you can choose the right interpretation.
Good reasons to use this category
- Finding a person’s completed age
- Counting weekdays between two dates
- Adding a known number of calendar days
- Checking ISO week or leap-year behaviour
Choosing the right operation
Use a calendar-date tool when the question is about dates on a page, and a duration tool when elapsed clock time matters. For a deadline across time zones, convert the times explicitly before relying on a local-device result.
Know the boundary
A browser knows the device’s time zone, not your organisation’s holiday calendar. Business-day calculations accept the holidays you provide and do not infer public holidays. Always check daylight-saving and jurisdiction-specific rules for consequential schedules.