Date Calculator

Pick a start date, choose add or subtract, and enter days, weeks, months, or years. The result date appears first, followed by the weekday and a short operation summary.

Days and weeks are counted as calendar days. Months and years are applied as calendar units, then the remaining week and day amounts are applied.

Some month additions are ambiguous. For example, adding one month to January 31 points to a month that may not have 31 days. This calculator clamps that result to the last valid day of the target month and shows the final date clearly.

The same rule applies to leap years: adding one year to February 29 clamps to February 28 when the result year is not a leap year. Days and weeks are applied after calendar months and years.

Use it for planning follow-ups, checking future dates, estimating project dates, reminders, and scheduling examples. For days between two dates, use the date duration calculator. For weekday-only ranges, use the business days calculator. To find the weekday for the result date, use the weekday calculator. To find the ISO week number for a date, use the week number calculator. To compare completed months between two dates, use the months between dates calculator. To count days until a target date, use the days until calculator. For a live countdown to a date, use the event countdown. For hours and minutes, use the time calculator.