Time and Date calculators help you work with days, dates, and durations — count the days between two dates, add or subtract time, convert time zones, and read lunar or perpetual calendars. Popular tools include the Date Duration Calculator, Date Calculator, Lunar Calendar Converter, UTC to PST Converter, and Decimal Hours to HH:MM Calculator.
Choose a tool below for an instant answer, or open the Trending tab to see what's in demand this week. Every calculator is free and works on any device.
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Dog Age in Human Years CalculatorConvert your dog's age into human years using the science-based logarithmic formula (16·ln(age)+31), with a linear puppy approximation under 1 year.
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Weekly Time Card CalculatorAdd up your weekly work hours from daily clock-in/clock-out times and breaks. Handles overnight shifts and splits regular vs overtime hours over 40.
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Average Speed from Time and Distance CalculatorCalculate average speed from distance and time. Enter distance in km, miles, or meters plus hours, minutes, and seconds to get km/h, mph, and m/s.
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Minutes Per Mile to MPH CalculatorConvert your running or walking pace in minutes per mile to speed in miles per hour (mph). Enter minutes and seconds to get instant mph and km/h.
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Decimal Hours to HH:MM CalculatorConvert decimal hours to hours and minutes (HH:MM) instantly. Enter a value like 2.75 to get 2h 45m. Free, accurate decimal time converter.
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Time Between Now and Future Date CalculatorCalculate the exact time between now and a future date and time — total days, hours, minutes and seconds plus a clean day/hour/minute/second breakdown.
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Time From Speed and Distance CalculatorCalculate how long a trip takes from distance and speed. Enter distance and speed (km/h or mph) to get travel time in hours, minutes, and seconds.
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How Many Weeks Until a Date CalculatorFind out how many full weeks remain until any future date. Enter a target date and instantly see the weeks and days left from today.
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Days Between Dates CalculatorFind the exact number of days between two dates. Enter a start and end date to get the total days, signed difference, and weeks between them.
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How Many Months Until a DateFind how many whole months remain from today until a future date. Free month countdown calculator with day-of-month adjustment and a years estimate.
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Flight Arrival Local Time CalculatorCalculate your flight's local arrival time across time zones. Enter departure time, flight duration, and origin/destination UTC offsets to get arrival time.
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How Old Was I When... CalculatorFind out exactly how old you were when a past event happened. Enter your birth date and the event date to get your age in years, months and days.
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Army Leave Days Accrual Calculator (US)Estimate US Army leave accrual at 2.5 days per month, factoring in your starting balance and leave used, with the 60-day carryover cap applied.
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School Starting Age CalculatorFind out how old a child will be on the school cutoff date and whether they meet the minimum starting age. Enter birth date, cutoff date, and required age.
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Alarm Time CalculatorFind what time to set your alarm. Add bedtime, time to fall asleep, and desired sleep hours to get your exact 24-hour wake-up time.
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Hours Until a Given Time CalculatorFind how many hours and minutes remain until a given time of day. Enter the current time and target time to get the countdown on a 24-hour cycle.
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CST to UTC ConverterConvert Central Standard Time (CST, UTC−6) to Coordinated Universal Time (UTC). Enter any CST hour and minute to get the exact UTC time instantly.
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Monthly Salary to Hourly Rate CalculatorConvert your monthly salary to an hourly rate instantly. Enter your monthly pay and weekly hours to see your equivalent hourly wage, annual salary, and weekly pay.
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Age on a Specific Date CalculatorFind out exactly how old someone was (or will be) on any chosen date. Enter a birth date and target date to get age in years, months and days.
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When Will I Turn 21 Calculator (US)Find the exact date you turn 21 and reach the legal US drinking age. Enter your birthday to see the date and days remaining until you can legally drink.
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Pregnancy Weeks to Months CalculatorConvert weeks pregnant to months instantly. Enter your gestational age in weeks to see how many months pregnant you are, using 4.34524 weeks per month.
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Countdown to Deadline CalculatorCount the days, hours, and minutes remaining until any deadline. Enter a deadline date/time and the current time to see the exact time left or overdue.
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Days Until Ramadan CalculatorCount down the days and weeks until Ramadan. Enter today's date and your expected first day of Ramadan to see how long until the holy month begins.
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Army ETS Date CalculatorEstimate your US Army ETS date from your enlistment date and contract length. See days remaining, time in service, and percent of contract complete.
Frequently asked questions
What can I do with time and date calculators?
Find the number of days, weeks, or months between two dates; add or subtract a duration from a date; convert between time zones; work out ages and countdowns; and read lunar or perpetual calendars.
Do these handle time zones and daylight saving?
Time-zone converters use standard offsets; where daylight saving applies, check that your chosen date falls inside the DST period, since local rules change through the year.
Are they free and mobile-friendly?
Yes — free, no sign-up, and they work on any device.
How accurate are the date calculations?
Date math follows the standard calendar, including leap years. For legal or contractual deadlines, confirm the count against the specific rules that apply to you.
Which time and date tools are most popular?
This page lists them by usage, most popular first; the Trending tab shows what's rising this week.
