Count elapsed calendar days
October 1 to October 31 is 30 elapsed days. Think of the number of midnight boundaries between the dates. The start date itself is not an extra elapsed day.
Days Between Dates Calculator
Count calendar days for a project, an event, or a personal countdown. Choose whether to include the end date.
Days Between Dates Calculator
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How to use this calculator
Include both endpoints
For a list of dates that includes both October 1 and October 31, choose “Yes — include both dates.” The count becomes 31. The same start and end date gives zero elapsed days or one inclusive day.
Leap years and weeks
The calculation includes February 29 when it falls within the interval. It also expresses the total as complete seven-day weeks plus any remaining days. Thirty days is four weeks and two days.
Calendar days are not business days
Weekends and holidays are counted. This is not a legal, contractual, or filing-deadline calculator: such deadlines may have special start-day, holiday, and time-of-day rules. Use the count for ordinary planning and verify any formal deadline independently.
A LITTLE MORE CLARITY
Common questions
Does daylight saving time change the count?
No. The calculation compares calendar dates without local clock changes, so a day counts as one calendar day.
Can I count backward?
The end date must be on or after the start. Swap the two dates to find the interval between them.
About this tool
Created by Marchelle Cook at Roof & Ratio. These calculations run in your browser; entered values are not uploaded or saved by the calculator. Report a calculation issue with an example so we can review it.
Guide updated October 23, 2026. Displayed decimal results may be rounded; exact fraction and integer results are identified in the answer.