Best Date & Time Tools
A hand-checked list of the best free date & time tools for developers. Every tool runs in your browser — no upload, no login, no API key.
16 tools
Unix Timestamp Converter
Date & Time
Convert between Unix timestamps and human-readable dates.
Date Formatter
Date & Time
Format a date using custom patterns and Intl presets.
Timezone Converter
Date & Time
Convert a datetime across multiple IANA timezones at once.
Duration Calculator
Date & Time
Calculate the difference between two dates, or add/subtract time.
Age Calculator
Date & Time
Calculate exact age and countdown to the next birthday.
Cron Parser
Date & Time
Explain a 5-field cron expression and list upcoming run times.
ISO 8601 Converter
Date & Time
Convert dates and durations to and from ISO 8601 format.
Week Number Calculator
Date & Time
Find the ISO week number, day of year, and quarter for any date.
Business Days Calculator
Date & Time
Count business days between two dates, excluding holidays.
Countdown Timer Generator
Date & Time
Live countdown to any date and time.
Leap Year Checker
Date & Time
Check if a year is a leap year and find nearby leap years.
Work Hours & Timesheet Calculator
Date & Time
Total up work hours across shifts with breaks and hourly pay.
Day of Year Calculator
Date & Time
Convert a date to its day-of-year number, or back again.
Epoch Batch Converter
Date & Time
Convert a list of Unix timestamps to readable dates in bulk.
Stopwatch & Countdown Timer
Date & Time
Precision stopwatch with laps plus a countdown timer with alarm.
Pomodoro Timer
Date & Time
Focus timer with customisable work sprints and breaks.