Free Online Time & Date Calculators

Reading, Media & Leisure Time Calculators estimate how much time your entertainment habits actually take. Use the audiobooks calculator (reclaim dead time) to see how much listening time you can fit into a commute, or the binge watching calculator to plan how long it'll take to finish a show. The GWAM calculator (typing speed) measures gross words per minute for typing practice.

Sleep & Health Time Calculators track the timing side of sleep and daily health routines. Build a baby sleep schedule or check your biological clock/body clock calculator for natural sleep-wake timing, or use the fasting timer calculator to track an intermittent fasting window. The contraction timer helps time labor contractions, the medication schedule calculator keeps dosing on track, the melatonin timing calculator times supplementation for better sleep, and the ovulation date calculator tracks fertility timing.

Time & Date Calculators cover the everyday date and time math that comes up constantly. Calculate business days or day of the year, or use the calendar calculator and day counter to count days between events. The world clock calculator and sunrise/sunset calculator handle location-based time questions, while the epoch converter and Unix timestamp converter translate between human dates and computer timestamps.

This section also includes a chronological age calculator, birthday calculator, anniversary calculator, and countdown timer calculator for personal date tracking, plus leap year, moon phase, sidereal time, and Julian date converter tools for calendar and astronomical calculations, and a Roman numeral date converter, BC to AD calculator, and palindrome date finder for more unusual date questions.

Date Duration & Difference Calculators find exactly how much time separates two dates. Calculate the date difference or years between two dates, or use the months between two dates calculator and time between dates calculator for other duration units. Deadline-focused tools include the deadline calculator, project deadline tracker, contract expiration calculator, and warranty expiration calculator, while countdown calculators cover birthdays, weddings, holidays, retirement, and vacations.

This section also includes a working days calculator and business date to date calculator for counting only business days, plus a visa expiry countdown calculator and semester/term countdown calculator for time-sensitive deadlines.

Date Add/Subtract & Lookup Calculators find a date a set number of days, weeks, or months from a starting point. Use the date calculator (add/subtract) or add days calculator to project forward, or common fixed intervals like the 30 day calculator, 60 day calculator, 90 day calculator, and 6 month calculator. The day of week for any date calculator and doomsday calculator find what day of the week any date fell or falls on, while the next business day calculator and last day of month calculator handle business-specific date lookups.

This section also includes a week number calculator, quarter calculator, pay period calculator, and recurring date calculator for scheduling and payroll-related date lookups.

Time Arithmetic & Duration Calculators handle addition, subtraction, and elapsed time calculations down to the second. Calculate elapsed time or hours between two times, or use the time calculator (add/subtract/multiply/divide) for general time arithmetic. The stopwatch/lap time calculator and split time calculator track intervals during an activity, while the overtime hours calculator and break time calculator support payroll and work scheduling.

This section also includes a time calculator hh:mm:ss, add minutes calculator, minutes between two times calculator, and pace to time calculator for converting between pace and duration.

Age & Birthday Calculators find your exact age in whatever unit you need. Calculate age in years, months, and days, or break it down further with age in weeks, age in days, age in hours, age in minutes, and age in seconds calculators. The how old am I calculator and date of birth calculator work from either direction, while the half birthday calculator and age to birthday calculator find upcoming birthday milestones.

This section also includes a birth year calculator, birth from death date calculator, baby age calculator, and a pet age calculator (dog/cat years) for converting animal age to human-equivalent years.

Time Zone & World Clock Calculators solve the confusion of coordinating across time zones. Use the meeting planner (cross time zone) or conference call scheduler to find a time that works for everyone, or check the time zone overlap calculator for overlapping working hours. The UTC offset calculator and Zulu time (UTC) converter handle universal time conversions, while the DST (daylight saving time) calculator accounts for seasonal clock changes.

This section also includes a flight arrival time calculator, international call time calculator, international date line calculator, event time announcer, and time zone abbreviation lookup for other cross-time-zone planning needs.

Time Conversion & Format Calculators convert between the many ways computers and calendars represent time. Convert a Unix timestamp/epoch or use the ISO 8601 date/time converter and RFC 3339 date converter for standardized date formats, or the Excel serial date converter and Modified Julian date (MJD) converter for scientific and spreadsheet date systems. Developer-specific converters include LDAP/Active Directory timestamp, Mac HFS+ timestamp, SAS timestamp, and WebKit/Chrome timestamp converters.

This section also includes seconds to HH:MM:SS, minutes to hours, days to hours/minutes, weeks to days, and years to days/hours converters, plus a decimal time converter and binary/hex/oct time converter for less common time representations.

Calendar Systems & Converters Calculators convert dates between the Gregorian calendar and calendar systems used around the world. Convert to the Islamic (Hijri) calendar, Hebrew calendar, or Chinese calendar, or use the Persian (Jalali/Solar Hijri), Ethiopian, Coptic, and Buddhist calendar converters for other regional systems. The Julian calendar converter and Mayan calendar converter cover historical calendar systems, while the Chinese zodiac year calculator finds the zodiac animal for a given year.

This section also includes Afghan, Baháʼí, French Republican, Hanke-Henry Permanent, Indian National, Japanese, Kurdish, Ottoman fiscal, and Thai year converters, plus a Roman numeral converter (dates) and Seleucid era calculator for less common calendar systems.

Sun, Moon & Astronomy Calculators track celestial timing events visible from Earth. Calculate sunrise and sunset or day length for any location, or use the golden hour calculator and twilight duration calculator for photography planning. The moonrise and moonset calculator and moon distance calculator track lunar timing and position, while the equinox and solstice calculator and seasons calculator mark the astronomical start of each season.

This section also includes a solar noon calculator, planet rise and set calculator, star visibility calculator, meteor shower calendar calculator, eclipses worldwide calculator, solar/lunar eclipse countdown, Islamic prayer times calculator, and zodiac sign date calculator for other sky-watching and astronomical timing needs.

Work Time & Payroll Calculators track hours worked and time-based pay. Calculate weekly work hours or annual working hours, or use the timesheet calculator and shift planner calculator for scheduling and time tracking. The billable hours calculator and freelancer rate calculator (time-based) help freelancers and contractors bill accurately, while the hourly pay calculator (time-based) and PTO accrual calculator handle payroll and leave tracking.

This section also includes a work-life balance calculator and time spent on email calculator for measuring how work time is actually spent.

Timers & Countdowns Calculators count down to a specific date or event. Use the countdown to any date calculator for a custom countdown, or seasonal favorites like the Christmas countdown, New Year countdown, and winter countdown. The exam countdown calculator and tax deadline countdown help track important deadlines, while the time since event calculator counts up from a past date instead of down to a future one.

Historical & Special Date Calculators explore dates from history and cultural calendars. Calculate the Easter date or Chinese New Year date for a given year, or use the on this day in history calculator and days since historical event calculator to explore what happened on a specific date. The century calculator and millennium calculator mark larger spans of time, while the reign/dynasty duration calculator tracks how long a historical ruler or era lasted.

This section also includes a generation calculator, historical age calculator, Diwali date calculator, seconds/days since year 0 calculator, and an epoch/timestamp list (historical dates) for exploring significant dates across history.

Developer & Technical Time Tools Calculators handle the timestamp and scheduling math that comes up in software development. Convert a database timestamp or batch of timestamps, or use the ISO 8601 duration calculator and timestamp difference calculator for API and logging work. The cron expression calculator and cron job next run calculator help schedule recurring jobs, while the JWT token expiry calculator and SSL certificate expiry calculator track security-related expiration dates.

This section also includes a UUID v1 timestamp extractor, log timestamp parser, date format string generator, API rate limit calculator, sprint/iteration duration calculator, TTL (time to live) calculator, and time complexity calculator for other developer-focused time and scheduling needs.