📅 Date-Time Calculators

Explore a curated set of free, accurate, and mobile-friendly date & time tools — Age Calculator, World Clock, Hours Calculator, Countdown Timer, Workdays, Epoch Converter and more. No signup required.

Age Calculator

Find exact age in years, months, days. Useful for passports, applications and milestones.

Date Difference

Measure days between two dates including options to include/exclude end dates and weekends.

Countdown Timer

Set timers for events, reminders and launches with audible alerts and visual timers.

World Clock

View current time across multiple time zones, add cities, and plan global calls easily.

Hours Calculator

Calculate total hours and minutes between times—handy for timesheets and scheduling.

Workdays Calculator

Count business days between dates while excluding weekends and customizable holidays.

Epoch Converter

Convert Unix timestamps to human-readable dates and vice versa—useful for developers.

Stopwatch

Simple start/stop lap timer built for precision and reliability in-browser.

Calendar Generator

Create printable monthly calendars for any year with week numbers and custom start days.

Time Zone Converter

Quickly convert a time in one timezone to many other timezones, supporting DST rules.

Moon Phase

See moon phase for any date with rise/set approximations and illumination percentage.

Zodiac Calculator

Find your sun sign using birth date and read brief sign descriptions and compatibility notes.

Anniversary Tracker

Track, remind and compute upcoming anniversaries or important recurring dates.

Retirement Date

Estimate retirement dates, service durations and pension eligibility windows.

Project Deadline

Plan deadlines, add buffers, and compute milestone dates with working day options.

Why CalToo's Date & Time Calculators Save You Time (and Headaches)

Managing dates and times is a deceptively complex part of personal and professional life. Whether you are calculating someone’s exact age for legal paperwork, converting epoch timestamps for a software release, planning project milestones with working-day constraints, or coordinating a global meeting across time zones — small errors in date arithmetic can cascade into missed deadlines, incorrect paperwork, or frustrated teams.

That’s why a reliable suite of date-time calculators is essential. CalToo’s collection of tools is designed to be fast, mobile-friendly and precise. We emphasize clarity: each tool shows the required units, the formula or rule used, and contextual notes (for example, how Daylight Saving Time affects conversions in certain time zones, or how “inclusive” vs “exclusive” counting changes the date-difference result).

Common problems these tools solve

Who benefits from these calculators?

The audience for date-time tools is broad: students use them for assignments and learning; software developers convert and validate timestamps; HR and payroll professionals compute service durations and leave balances; event managers use countdowns and world clocks for international events; and individuals simply use an age calculator for important documents.

Design choices that matter

We built each calculator to be intuitive: default sensible units (e.g., days for date difference, seconds for epoch), provide optional advanced inputs (such as holiday lists for workday calculations), and include copy/export options where useful. Tools run fully in the browser so results are immediate and private — no data leaves your device unless you choose to copy or share them.

Accuracy, edge cases and transparency

Time calculations have edge cases: leap years, leap seconds (rare and handled conservatively), ambiguous local times during DST transitions, and differing business calendars across countries. Where these edge cases matter, our tools surface caveats and provide explanations so users know the assumptions behind a number. For mission-critical workflows, we recommend using these calculators for checks and combining them with authoritative local rules or APIs if you need legal-grade timestamps or compliance tracking.

Practical examples

Project Planning: Use Project Deadline and Workdays calculators to set milestones and allocate buffer time, ensuring delivery dates don't fall on holidays.
Software Debugging: Convert epoch timestamps with the Epoch Converter when reviewing logs from servers in multiple regions.
Event Coordination: Use World Clock and Time Zone Converter to pick meeting times that work for distributed teams and avoid repeated rescheduling.

Tips for best results

Final thoughts

Time is finite; errors in how we measure and coordinate it cost time, money and trust. CalToo’s Date-Time Calculators are made to reduce friction, remove ambiguity, and help you get precise answers quickly. Bookmark this page, try a few example inputs, and use these tools whenever date or time precision matters.