Date & Time Tools
Timezones, date calculations, week numbers, world clocks, and more — every utility in one place, free and account-free.
Timezone Converter
Convert time between any two cities or timezones. 400+ IANA zones, DST-aware, with a meeting planner for international calls.
Time in Cities
Current local time in 30 major cities — Sofia, London, New York, Tokyo, and more. Live clocks with DST status.
Timezone Abbreviations
What do EST, GMT, CET, IST mean? Plain-language explanations of each popular abbreviation with UTC offset, regions, and DST transitions.
Date Calculator
Calculate the difference between two dates, add or subtract days/months/years. Includes 10 Bulgarian holiday shortcuts with "days-until" badges.
Week Number
What week number is it today? Full ISO 8601 week table for any year, the current week highlighted, and an explanation of ISO vs US systems.
Today in History
What happened on this date? Chronological list of historical events from ancient times to today, updated daily.
Frequently asked questions
Which tool should I use to plan an international meeting?
The timezone converter includes a built-in meeting planner — add every participant, see the overlapping working hours, and pick a slot that works for everyone.
Is daylight saving time (DST) supported?
Yes. Every tool uses the IANA Time Zone Database (Olson) and applies DST transitions automatically for each zone. The converter also highlights upcoming transitions.
What is the difference between the ISO and US week-numbering systems?
ISO 8601 starts the week on Monday; week 1 is the one containing the first Thursday of the year. The US system starts on Sunday; week 1 is the one containing 1 January. The Week Number page explains both.
Are the tools free?
Yes, every date and time tool is fully free, ad-free, and works without an account.
How do I explain EST, GMT, or CET to a colleague?
Open the timezone abbreviations page — each popular abbreviation has its own page with the UTC offset, the countries that use it, and the matching IANA zone.