Every date & time tool,
in one elegant place.
ddhhmmss is the complete date & time toolkit — find every possible date and time related tool and resource in one place: world clock, time-zone converter, countdown & Pomodoro timers, stopwatch, alarms, date, age & business-day calculators, Unix timestamp converter, sun & moon times, DST tracker and more. Free, fast, no sign-up.
Clocks
3 toolsTimers
5 toolsCountdown Timer
Precise countdowns with presets & alarm.
Open Countdown Timer →⏲Online Stopwatch with Laps
Millisecond timing with lap splits.
Open Online Stopwatch with Laps →◔Pomodoro Timer
Focused intervals with a clean ring.
Open Pomodoro Timer →⟳Interval Timer
Work / rest cycles with rounds.
Open Interval Timer →◉Online Alarm Clock
Multiple labelled alarms, any zone.
Open Online Alarm Clock →Converters
5 toolsMilliseconds to HH:MM:SS.mmm Converter
Milliseconds ⇄ readable time.
Open Milliseconds to HH:MM:SS.mmm Converter →″Seconds to HH:MM:SS Converter
Seconds ⇄ readable time.
Open Seconds to HH:MM:SS Converter →′Minutes to HH:MM:SS Converter
Minutes ⇄ readable time.
Open Minutes to HH:MM:SS Converter →▤Calendar Converter
One date in 10 world calendars.
Open Calendar Converter →ⅫRoman Numerals Date Converter
Dates ⇄ Roman numerals.
Open Roman Numerals Date Converter →Work & Productivity
6 toolsHours Calculator
Weekly time card from clock-in / clock-out.
Open Hours Calculator →▤Business Days Calculator
Working days, minus real holidays.
Open Business Days Calculator →∑Time Calculator
Add or subtract hours, minutes, seconds.
Open Time Calculator →☽Sleep Calculator
Bedtimes & wake times by sleep cycle.
Open Sleep Calculator →▦Weekly Planner & Timetable
Editable, printable weekly timetable.
Open Weekly Planner & Timetable →¶Reading Time Calculator
How long to read or speak a text.
Open Reading Time Calculator →Date Tools
10 toolsDate Calculator
Differences, day shifts, business days.
Open Date Calculator →±Date & Time Calculator
Add/subtract time from a date & time.
Open Date & Time Calculator →✦Event Countdown Timer
Live countdown to any date.
Open Event Countdown Timer →❖Age Calculator
Exact age plus totals & next birthday.
Open Age Calculator →⇅Age Difference Calculator
Exact age gap between two people.
Open Age Difference Calculator →▥Day of the Week Calculator
What day of the week is any date.
Open Day of the Week Calculator →⊛Leap Year Calculator
Check if any year is a leap year.
Open Leap Year Calculator →▣Today's Date
Today’s date, week number, day of year.
Open Today's Date →#Week Number
Current ISO week + any date’s week.
Open Week Number →◕Year Progress
Live year, month, week & day bars.
Open Year Progress →Astronomy
2 toolsDeveloper
3 toolsExplore
All your date & time needs, in one toolkit
ddhhmmss is the complete date & time toolkit — find every possible date and time related tool and resource in one place: world clock, time-zone converter, countdown & Pomodoro timers, stopwatch, alarms, date, age & business-day calculators, Unix timestamp converter, sun & moon times, DST tracker and more. Free, fast, no sign-up. Whether you are coordinating a meeting across continents, timing a workout, counting down to a big day, normalising timestamps in code, or just checking what time it is on the other side of the world, you will find the right tool here — and more are added over time.