Date & Time tools
Age and date-difference calculators, countdown timers, work-day and timesheet math, time zone conversion, and a few specialty tools like moon phase and sunrise/sunset calculators. Every calculation runs against your device's own clock and timezone data.
18 tools
Date & Time tools guides
Unix Timestamps Explained: Why Computers Count Time in Seconds Since 1970
A Unix timestamp like 1798000000 means nothing to a human at a glance, but it's the format nearly every computer system uses internally to represent a moment in time - and the reason comes down to a decision made in the early 1970s.
How to Calculate Age Correctly (Leap Years Included)
'Subtract the birth year from the current year' gets the wrong answer for roughly three-quarters of the days in a year, and leap years complicate the exact day count even once the year and month are handled right.
How Time Zone Conversion Actually Works
Why a fixed UTC offset silently breaks twice a year, how real timezone conversion handles daylight saving automatically, and what to check before scheduling across regions.
How to Calculate the Days Between Two Dates (It's Trickier Than Subtracting)
Why calendar math has more edge cases than it looks like: inclusive vs exclusive counting, variable month lengths, and the difference between calendar days and business days.
Frequently asked
Are these tools actually free?
Yes. Every tool on this page is free to use, with no usage limits, watermarks, or paywalled features.
Is my file or data uploaded to a server?
No. Every tool listed here processes your file or input directly in your browser tab; nothing is sent to YourFileKit's servers or any third party.
Do I need to create an account?
No sign-up is required to use any tool. An optional account only exists for saving preferences like favorites across visits.
Do time zone conversions use my device's clock, or a fixed reference?
Time Zone Converter and World Clock read your device's own timezone database, so results reflect real, current DST rules, not a hardcoded offset that goes stale after a DST changeover.
Can I use these for scheduling across time zones?
Meeting Time Planner is built specifically for that: enter a time and see it converted across everyone's time zones side by side.