Date and time calculators

Work out an exact age from any date of birth. Enter the birth date below to see the age in years, months and days, the total days and weeks lived, and the number of days until the next birthday.

Count the working days between two dates. Pick a country and the calculator removes weekends and that country's public holidays, so you see the real number of working days in the range.

Convert a dog's age into human years. This calculator uses the modern size-aware method rather than multiplying by seven, because a dog's first two years age much faster than the years after them.

Convert a cat's age into human years. Like dogs, cats age quickly in their first two years and then more steadily, so this calculator uses a stepped method rather than a single multiplier.

Estimate a due date and see how far along a pregnancy is. Choose the method that fits the information you have: last menstrual period, conception date, IVF transfer date, or a dating ultrasound.

Build a live countdown to any date. Enter a date, an optional time and an event name, then share the link so anyone can watch the same countdown tick down.

Estimate the day you ovulate and the fertile window around it. Enter the first day of your last period and your usual cycle length to see your most fertile days and your next predicted period.

Estimate when conception is likely to have happened. Work it back from a known due date, or forward from the first day of your last period and your cycle length.

Work out a due date from an IVF embryo transfer. Because IVF timing is known precisely, the estimate is counted straight from the transfer date, with a separate rule for day-3 and day-5 transfers.

Find out which trimester you are in now, and see the dates each trimester begins and ends. Enter your information using whichever method you have: last period, conception date, IVF transfer or a dating ultrasound.

Find out how many weeks and days pregnant you are right now. Enter the first day of your last period, or your estimated due date, to see your current week, trimester, percentage complete and the days left to 40 weeks.

Plan the run-up to any exam. Enter your exam date and the total study hours you are aiming for, and this calculator shows the days left and the hours per day you need to stay on track. For exam-specific results dates, use the CPA, bar exam and USMLE planners linked below.

Plan a CPA exam section and see when your score is likely to be released. Choose your section, enter your test date and a study hours target, and the calculator shows the days left, the hours per day to reach your target, and the AICPA target score-release date for that testing window.

Plan your bar exam preparation and see when results are usually released. Choose your state, enter your exam date and a study hours target, and the calculator shows the days left, the hours per day to reach your target, and the typical results-release date for your jurisdiction and sitting.

Plan a dedicated USMLE study block and see when results are usually reported. Choose your Step, enter your test date and a study hours target, and the calculator shows the days left, the hours per day to reach your target, and a typical results date.