Free online tools to calculate days between dates, add or subtract days, find your exact age, and more.
Calculate the exact number of days between any two dates.
CalculateFind a future or past date by adding or subtracting days.
CalculateKnow your precise age in years, months, days & hours.
CalculateFind what day of the week any date falls on + history.
CalculateDateCalc offers four essential date calculation tools, perfect for project planning, age tracking, event countdowns, and historical date research. All calculations account for leap years and varying month lengths automatically.
Calculate the exact number of days between any two dates. Useful for tracking project timelines, calculating rental periods, counting days until a deadline, or figuring out how many days between two historical events. The tool shows results in days, weeks, and also breaks it down into years, months, and days.
Pick a start date and add or subtract any number of days to find the resulting date. Perfect for calculating delivery dates, warranty expiration, due dates, or "what date will it be in 90 days?" scenarios. Supports both positive (future) and negative (past) day counts.
Enter your birth date to get your precise age in years, months, days, and even hours. The tool also shows your next birthday countdown, total days lived, and your birth day of the week. Fun for birthday parties or answering "how old am I in days?"
Enter any date to find out what day of the week it falls on. Works for past and future dates. Great for planning events ("What day is Christmas 2026?"), historical research ("What day was July 4, 1776?"), or scheduling. Also shows notable events that happened on that date in history.
Our calculator fully accounts for leap years using the Gregorian calendar rules: a year is a leap year if divisible by 4, except centuries (divisible by 100), unless also divisible by 400. So 2024 is a leap year, 1900 was not, but 2000 was. This affects February (28 vs 29 days) and the total days in a year (365 vs 366).
Calendar days include all days (weekends and holidays), while business days typically only count Monday through Friday, excluding public holidays. DateCalc currently calculates calendar days. For business day calculations, a general rule of thumb: multiply business days by 7/5 to estimate calendar days, or subtract weekends manually.
The calculator works best with dates in the Common Era (CE/AD). For very ancient dates, accuracy depends on the calendar system used. The Gregorian calendar we use was only adopted in 1582, and dates before that were under the Julian calendar (which had slightly different leap year rules). For most practical purposes, dates from year 1 to 9999 work accurately.
Our age calculator is precise to the day. It correctly accounts for varying month lengths and leap years when calculating the difference. The hours/minutes display uses a simplification (24 hours per day) from midnight. For legal purposes, age is typically determined by the date alone, not the time of birth.
This is correct! January has 31 days, so from Jan 31: the remaining 0 days in January + 28 days in February (non-leap year) + 2 days in March = 30 days, landing on March 2nd. Our calculator adds exact days rather than months, which avoids the ambiguity of "one month" (28, 29, 30, or 31 days?).
The Gregorian calendar repeats every 400 years exactly (146,097 days). The 13th of a month is slightly more likely to fall on a Friday than any other day. February is the only month that can pass without a full moon. The year 2026 starts on a Thursday. Try entering your birthday to discover what day of the week you were born!
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