Free Online Time & Date Tools

What Each Tool Does

Every tool below opens instantly, needs no account, and processes your data locally in your browser. Here is what each one is for:

Date Diff

The exact gap between any two dates in years, months, weeks and days — for deadlines, anniversaries and contracts. Open the Date Diff →

Age

Precise age in years, months and days from a birth date — plus total days lived and next-birthday countdown. Open the Age →

Countdown

A clean, full-screen countdown for launches, exams, cooking and deadlines, with an alert when time's up. Open the Countdown →

Stopwatch

A precise browser stopwatch with lap times — no app install, no login, just start. Open the Stopwatch →

Pomodoro

Focused 25-minute work sessions with automatic breaks — the classic Pomodoro technique in your browser. Open the Pomodoro →

World Clock

Live clocks for multiple cities side by side, so distributed teams and travelers stay oriented. Open the World Clock →

Day of Year

See today's day number (1–366), the ISO week, and how much of the year is behind you. Open the Day of Year →

Days Until

Count the days remaining to any future date — trips, releases, weddings, retirement. Open the Days Until →

Work Hours

Log start and end times, subtract breaks, and total your working hours for timesheets and invoices. Open the Work Hours →

Meeting

Compare working hours across time zones to find meeting slots that are humane for everyone. Open the Meeting →

Analog Clock

A live ticking clock face you can also set manually by dragging the hands or typing a time. Open the Analog Clock →

Zodiac Sign

Enter a birth date to find its Western zodiac sign, symbol and element, with the full 12-sign reference table. Open the Zodiac Sign →

Average Time

Correctly averages a list of clock times using circular mean math, so times that straddle midnight don't break. Open the Average Time →

Julian Day

Convert any calendar date to its Julian Day Number and back — for astronomy, genealogy and legacy systems. Open the Julian Day →

Date Sorter

Paste a messy list of dates and sort them ascending or descending, with unparseable lines flagged. Open the Date Sorter →

Military Time

Convert 24-hour and 12-hour AM/PM time in both directions, live as you type. Open the Military Time →

Day of Week

Find what day of the week any date fell — or will fall — on. Open the Day of Week →

Time Difference

Work out the duration between two times of day, like a shift or a session length. Open the Time Difference →

Interval Splitter

Split a time range into equal slots by count or by length — handy for scheduling back-to-back meetings. Open the Interval Splitter →

Until Midnight

A live countdown showing exactly how much of today is left, down to the second. Open the Until Midnight →

Dog Age

Estimate a dog's age in human-equivalent years using a size-adjusted curve, not the old ×7 myth. Open the Dog Age →

Cat Age

Convert a cat's age to human-equivalent years using the commonly accepted modern conversion table. Open the Cat Age →

Random Date

Generate one or many random dates inside a date range you choose, with an optional no-duplicates mode. Open the Random Date →

Date Validator

Check whether a date string is a real calendar date and see exactly why it isn't if it's invalid. Open the Date Validator →

Friday the 13th

List every Friday the 13th in a year or year range. Open the Friday the 13th →

How to Choose the Right Tool

For calendar questions, Date Difference measures the exact span between two dates, Days Until counts down to a target, Day of Year tells you where you are in the year, and the Age Calculator turns a birth date into precise years, months and days. For live timing, choose the Stopwatch for counting up, the Countdown Timer for counting down, and the Pomodoro Timer for focused work sessions with breaks. The World Clock shows multiple cities at once, the Meeting Scheduler finds overlap across time zones, and the Work Hours Tracker adds up your shifts for the week.

Frequently Asked Questions

Do the timers keep running if I switch tabs?

Yes — timers keep accurate time in the background and update the moment you return to the tab.

Does the age calculator account for leap years?

Yes. All date tools use the browser's calendar arithmetic, which handles leap years and month lengths exactly.

Can I track work hours across multiple days?

Yes — the Work Hours Tracker lets you log multiple time ranges and totals them, including overnight shifts.

Do these tools know my location or calendar?

They only use your device's clock and time zone setting, and nothing is transmitted anywhere.

Explore More WiserWork Categories

WiserWork offers 423 free browser-based tools across 26 categories — all private, all free, no sign-up required.