Time
Browse 6 professional tools
Age Calculator
Cron Expression Builder
Date Difference Calculator
Pomodoro Timer
Timestamp Converter
World Clock
Time tools cover the gap between "what time is it" (trivial) and "what time was Unix timestamp 1747353600 in São Paulo on a DST transition Sunday" (annoying). Most of them are inspection — converting between Unix / ISO / RFC formats, computing date differences with country-specific business calendars, validating cron expressions across dialects.
Timestamps & calendars
Unix seconds vs milliseconds (the most common bug source), ISO 8601, RFC 2822. World clock handles all 600+ IANA timezones with DST rules. Date difference includes 30+ country holiday calendars for accurate business-day counts.
Convert Unix timestamps to human-readable dates and vice versa. Support for milliseconds, seconds, ISO 8601, RFC 2822 formats. Free epoch converter online
View current time in multiple cities and timezones. Compare time zones, find time difference. Free world clock with daylight saving support
Calculate days between dates, working days excluding weekends and holidays. Add/subtract time from dates. Support for Poland, USA, Germany, UK, France holidays
Calculate exact age in years, months, days from birthdate. Find days between two dates, upcoming birthday countdown. Free online age calculator
Schedules & cron
Cron syntax varies by dialect (POSIX, Quartz, Kubernetes, AWS EventBridge — each with subtly different semantics). The day-of-month / day-of-week OR-vs-AND gotcha is the source of most "why is my cron running every Friday" bugs.
Productivity timers
25/5 classic Pomodoro plus customizable rhythms (52/17, 90/20). The research finding is that it is the rhythm and the break, not specifically 25 minutes, that does the work. Adjust to your task.
Frequently asked questions
Why does my Unix timestamp give the wrong date?
Almost always: confusion between seconds and milliseconds. Unix epoch is in seconds; JavaScript Date.now() is in milliseconds. A timestamp like 1747353600000 (13 digits) is milliseconds; 1747353600 (10 digits) is seconds. Multiply or divide by 1000 to convert.
How do I store dates across timezones?
Store UTC timestamps in the database, plus the IANA timezone identifier (Europe/Warsaw, America/New_York) if the original local time matters. Never store "2024-01-15 14:00 local" without a zone — you cannot tell what that means. Compute local times on display.
Why does my cron skip Mondays?
Probably day-of-week numbering. Standard cron: 0 = Sunday. Quartz: 1 = Sunday, 7 = Saturday. AWS EventBridge: 1 = Sunday. Same expression behaves differently across dialects. Test against the actual scheduler's docs.
How do I count business days excluding holidays?
Use Date Difference Calculator with the relevant country selected — it includes statutory holidays for 30+ countries. For multi-jurisdiction contracts, name the calendar explicitly ("business days per [country]") to avoid ambiguity.
Last updated · E-Utils editorial team