What each mode does
Days between counts the full days separating two dates — useful for contract terms, project timelines, or figuring out someone's exact age in days. Days until counts down from today to a future date, or shows how many days have passed if the date is in the past. Add or subtract takes a starting date and shifts it forward or backward by a number of days — handy for deadlines like "30 days from the invoice date."
A note on how days are counted
This tool counts full calendar days between the two dates you enter, not including partial days or time of day. If you need business days only (excluding weekends), subtract roughly 2 days for every 7 in the result as a rough estimate, or count manually for exact figures around holidays.