Free Online Date & Time Difference Calculator
Utilsly's date & time difference calculator is a completely free, browser-based tool that calculates the exact difference between any two dates and times — down to the second. No signup, no data sent to any server. Works offline once the page is loaded.
How to Calculate the Number of Days Between Two Dates
Enter your start date and end date using the date pickers. The days between dates calculator instantly shows the difference in years, months, days, hours, minutes, and seconds — along with the total count in each individual unit (e.g. total days, total hours, total minutes, total milliseconds). The result updates automatically as you change either date.
Working Days Calculator (Business Days)
The tool automatically calculates the number of working days (business days) between your two selected dates, excluding weekends (Saturday & Sunday) and major US federal holidays through 2026. This is useful for project planning, deadlines, payroll calculations, contract durations, and HR processes.
Weekday Breakdown
The weekday breakdown section shows exactly how many Mondays, Tuesdays, Wednesdays, etc. fall within your selected date range — useful for scheduling recurring meetings, counting billing days, or planning shift rotations.
Add or Subtract Days / Months / Years to a Date
Use the "Add / Subtract" tab to add or remove any number of years, months, weeks, days, hours, minutes, or seconds from any base date. The result shows the exact resulting date with full metadata including week number, day of year, quarter, and Unix timestamp. Results update automatically as you adjust values.
Timezone Converter
The timezone converter tab lets you convert a single date and time into up to 4 different timezones simultaneously. Supports all major world timezones including UTC, US, European, Asian, African, and Pacific zones. Handles daylight saving time (DST) automatically.
World Clock
The World Clock tab shows the live current time in 10 major cities around the world, updated every second. Includes the UTC offset and timezone name for each city.
Countdown Timer
Set a target date for any upcoming event — a birthday, holiday, project deadline, or custom milestone — and get a live countdown timer in years, months, days, hours, minutes, and seconds. Save up to 5 countdowns for quick reference. Quick presets include Christmas, Halloween, New Year, and more.