This calculator works with whole calendar dates. Use it to move a date forward or backward by years, months, weeks and days, or to measure the exact span between two dates without counting time zones or daylight saving.
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Enter a start date The result appears here once the dates and values are valid.
Result = Start + Y years + M months + W weeks + D days
Years and months are applied first, then weeks and days. When the target month is shorter, the day is clamped to the last valid day instead of overflowing into the next month.
Difference = whole years, months and days from start to end
The calculator compares calendar dates, so month lengths and leap days are respected. The total days and weeks are counted independently of the years/months split.
Inclusive total days = exclusive total days + 1
Ticking “Include end date” counts the later date as a whole day. For a one-day event on 1 May, the exclusive span is zero days and the inclusive span is one day.
A monthly renewal starts on 31 January 2024.
The next renewal date is 29 February 2024. The month is not allowed to overflow into March.
Measure the span between the start of January and the start of March in a leap year.
The exclusive difference is 60 days because February 2024 has 29 days. With the end date included, the total becomes 61 days.
Adding one month to 31 January gives the last day of February, not 2 or 3 March. This rule applies to every month and every leap year.
29 February is a real date only in leap years. Adding a year to 29 February 2024 gives 28 February 2025, and date differences use the actual number of days in each month.
The difference is reported as an absolute span with a short note. The tool does not silently swap your dates or return a negative age.
Times of day are ignored. Because the maths runs on calendar dates, a daylight-saving change cannot shift a result by one day.
The result is the last day of February: 28 February in a normal year and 29 February in a leap year. The calculator clamps instead of overflowing into March.
No time zone is applied. You enter calendar dates and the calculator compares them as dates, so results do not shift because of UTC offsets or daylight saving.
It adds one day to the total, treating the later date as a full day. The years/months/days and total days are both recalculated with the extra day.
Yes. Choose “Subtract from a date” and enter the parts to remove. The result date and weekday are shown in the same way as for addition.
2024 is a leap year, so February has 29 days. January has 31 days, giving 31 + 29 = 60 days from 1 January to 1 March.
The calculator reports the absolute difference and adds a note that the end date is earlier. It never returns a misleading negative number of days.