Why use this calculator
Whether you're counting down to a holiday, a wedding, a contract deadline, or a baby's due date, this calculator tells you exactly how many days you have left — and converts it to weeks and months for perspective.
How to use it
Enter the year, month, and day of your target date. The calculator shows the number of days until (or since) that date, along with weeks, months, and the day of the week it falls on.
The formula
Days = (Target Date − Today) in milliseconds ÷ 86,400,000. Weeks = Days ÷ 7. Months = Days ÷ 30.44 (average days per month).
Worked examples
Days until Christmas (December 25)
Varies — shows exact days, weeks, and months remaining
A date in the past
Shows days since that date — useful for anniversaries
When people use it
- Countdown to a holiday or vacation
- Days until a project deadline
- Days until a lease or contract expires
- Days since an anniversary or start date
- Baby due date countdown
Tips
- For annual events (birthdays, Christmas), update the year each time
- 125 days ≈ 4 months — useful for quarterly planning
- There are 365 days in a year (366 in a leap year)
- Friday = 5, Saturday = 6, Sunday = 0 in day-of-week numbering
Questions people ask
- How many days until Christmas?
- Use this calculator — enter December 25 and the current or next year. Christmas is 359 days from January 1 in a standard year.
- How do I calculate working days instead of calendar days?
- Multiply calendar days by 5/7 for a rough estimate (excludes weekends). For exact business day calculations accounting for public holidays, check your state government's holiday calendar.
- What is the difference between calendar days and business days?
- Calendar days count every day including weekends and public holidays. Business days only count Monday to Friday, excluding public holidays. For financial and legal deadlines, verify which applies to your situation.