Date & Time Calculators

Work out durations, ages, deadlines, working days and time differences.

All date & time calculators

• Add Days CalculatorPick a start date, enter how many days to add, and get the new date together with its day of the week. A negative number counts backwards.
• Add Hours CalculatorEnter a start time and the hours and minutes to add or take away. The calculator shows the resulting clock time in both 24-hour and 12-hour form.
• Age CalculatorPick a starting point (a birth year, a full date of birth, or a known age) and the calculator works out the rest. With a full date you get an exact age down to the day.
• Age Difference CalculatorCompare two people by age, by exact date of birth or by birth year. Dates of birth give the most precise answer, down to months and days.
• Anniversary CalculatorChoose wedding, relationship or another event, enter the date, and see when the next anniversary falls and how long it has been so far.
• Birthday CalculatorFive birthday questions in one form: exact age, next birthday, birth year, weekday of birth, and date of birth from a known age.
• Business Days CalculatorCount how many working days fall between two dates, or find the date that lies a set number of business days from a start date. Weekends are always skipped, and you can add national public holidays for four countries.
• Calendar CalculatorTwo date tools in one: move a date forward or back by any mix of years, months, weeks and days, or measure how long it is from one date to another.
• Chronological Age CalculatorEnter a date of birth and, if you like, the date to measure the age on. The calculator returns the exact age in years, months and days along with the totals in months, weeks and days.
• Date & Time Duration CalculatorChoose the date duration tool to measure the span between two dates and times, or the time duration tool to compare two clock times. The answer is shown in every unit from years down to seconds.
• Day CounterPick a start date and an end date to count the calendar days between them. Choose whether the last day is included, and the workdays in the range are shown alongside.
• Day of the Week CalculatorPick a date and see whether it is a Monday, a Friday or any other day of the week. The guide shows how to work it out by hand with a simple formula.
• Days CalculatorUse the days calculator to find how many days lie between two dates, or to add days to a date and see the result with its day of the week. Weekdays, weeks and months are reported too.
• Hours CalculatorEnter a start time, an end time and an optional break to get the time in between as hours and minutes, decimal hours and total minutes. A second mode handles two full dates with times.
• Hours From Now CalculatorType how many hours ahead you want to look and the calculator gives the clock time you will reach, in 24-hour and 12-hour format. When the answer lands on another day, the date is shown too.
• Leap Year CalculatorTest a single year, list all the leap years in a range, or jump to the next one. The guide explains the rule that decides which years get a 29 February.
• Month Calculator & CounterCount whole months and leftover days between two dates, move a date forward by a number of months, or track monthly anniversaries. The guide shows exactly how the months are counted.
• Sleep CalculatorEnter the time you need to wake up and get a bedtime that fits whole sleep cycles, or enter your bedtime and get matching wake-up times. Age group, time to fall asleep and cycle length are adjustable.
• Time CalculatorUse the clock calculator to see what time it will be after adding or removing hours, minutes and seconds, or the date and time calculator to move a whole timestamp forwards or backwards.
• Time Card CalculatorPick a period of one to 31 days, enter when you clocked in, clocked out and how long you took for breaks, and the calculator totals your hours. Add an hourly rate and an overtime rule to see regular, overtime and gross pay.
• Years CalculatorPick a question, type one or two years and read the answer straight away: years between two years, how long ago a year was, or which year lies a set number of years back or ahead.