Date & Time Tools
Work with calendar dates, elapsed durations and explicit IANA time zones, including daylight saving transitions.
Age Calculator
Calculate completed years, months and days between two dates.
Date & TimeDate Difference Calculator
Compare calendar dates in days and weeks.
Date & TimeDays Between Dates
Count elapsed calendar days, excluding the end date.
Date & TimeBusiness Days Calculator
Count Monday–Friday days, optionally excluding listed holidays.
Date & TimeAdd Days to Date
Add calendar days with month and leap-year rollover.
Date & TimeSubtract Days from Date
Subtract calendar days from a date.
Date & TimeLeap Year Checker
Apply Gregorian century and 400-year leap rules.
Date & TimeWeek Number Calculator
Find the ISO week number and ISO week-year.
Date & TimeUnix Timestamp Converter
Convert Unix seconds to an ISO UTC instant.
Date & TimeUnix Timestamp Generator
Convert an ISO instant with explicit offset to Unix seconds.
Date & TimeISO 8601 Converter
Normalize an offset-qualified instant to ISO 8601 UTC.
Date & TimeTimezone Converter
Convert a wall-clock time between IANA zones and flag DST ambiguities.
Date & TimeUTC to Local Time
Display a UTC instant in a specified IANA zone.
Date & TimeLocal Time to UTC
Resolve a local time to UTC with an explicit DST ambiguity choice.
Date & TimeTime Duration Calculator
Calculate elapsed seconds between two offset-qualified instants.
Date & TimeHours to Minutes Converter
Multiply decimal hours by 60.
Date & TimeMinutes to Seconds Converter
Multiply decimal minutes by 60.
Date & TimeCountdown Calculator
Measure seconds remaining until a specified instant.
Date & TimeDate Format Converter
Format a Gregorian calendar date in a chosen pattern.
Date & TimeTime Format Converter
Convert 24-hour clock input to a 12-hour display.
Date & TimeDay of the Week Calculator
Find the English weekday of a validated Gregorian calendar date, using UTC to avoid local shifts.
Date & TimeJulian Date Converter
Convert an ISO instant with explicit offset to astronomical Julian Date. This is a continuous day count, not the Julian calendar.
Date & TimeDiscord Timestamp Generator
Generate Discord timestamp markup from an ISO instant with explicit offset and a supported display style.
Date & TimeTime Calculator
Add or subtract signed HH:MM:SS durations. Hours may exceed 24; minutes and seconds must be below 60.
Date & TimeOnline Stopwatch
Start, pause and reset a monotonic elapsed-time display; lap times are recorded locally. This interface works locally in your browser.
Date & TimeCountdown Timer
Start a countdown from an entered number of seconds. Browser tab throttling can delay visual updates; deadlines use elapsed time. This interface works locally in your browser.
Date & TimePomodoro Timer
Alternate entered work and break intervals with start, pause and reset controls. No notification or external service is required. This interface works locally in your browser.
Date & TimeChoose the right date & time tool
Each utility lists its accepted inputs, working example and result limitations. Start with the task you need, then use the related utilities to check or transform its output.
Frequently used in this category
- Age Calculator — Calculate completed years, months and days between two dates.
Frequently asked questions
How are daylight-saving changes handled?
Timezone conversion uses IANA zone rules. A repeated local time requires an earlier or later choice; a nonexistent time is rejected rather than silently shifted.
Do business days include public holidays?
Business days mean Monday through Friday, excluding the end date. Public holidays are excluded only when you supply their dates.