How to count the days between two dates
- Pick a start date and an end date.
- Choose whether to include the end date.
- Read the result in days, in years/months/days, in weeks, and as business days.
Examples
- Countdown: set the start to today and the end to an event date to see how many days are left.
- Deadlines: check how many working days you have before a contract or project deadline.
- Anniversaries: find out exactly how long you have been in a job, relationship or home.
- Notice periods and billing: calculate the days covered by an invoice or rental period.
Need an exact age instead? Use the Age Calculator. Working with timestamps? Try the Unix Timestamp Converter.
Inclusive vs. exclusive counting
By default the calculator counts the days between two dates: from Monday to Friday of the same week is 4 days. Turn on “Include end date” to count both the start and end day, which gives 5. Use inclusive counting for things like vacation days, hotel nights plus checkout day, course durations and contract terms that say “from and including”. Use the default for countdowns and “how long ago” questions.
How months and years are counted
Months have different lengths, so “1 month” is not a fixed number of days. The calculator counts whole calendar months first and then remaining days: from 31 January to 1 March 2024 is 1 month and 1 day. If you need an exact figure for billing or interest, use the total days figure instead of months.
Business days
The business day count includes Monday to Friday and excludes weekends. Public holidays are not removed automatically because they differ by country, state and even company. Subtract the holidays that apply to you, for example, a 10-business-day delivery window that includes Christmas Day and Boxing Day in the UK becomes 12 weekdays long.
Practical examples
- Pregnancy and baby age: count weeks from a start date using the weeks figure.
- Visa and residency rules: check how many days you have stayed in a country between two dates.
- Payment terms: “Net 30” means 30 days after the invoice date.
- Fitness and habits: see how many days a streak has lasted.
Counting weeks and months for pregnancy and age
For anything measured in weeks, such as pregnancy, a baby’s age or a training plan, use the weeks figure, which shows whole weeks plus remaining days. For example, 100 days is 14 weeks and 2 days. Months are less precise because they vary from 28 to 31 days, so medical and legal contexts usually prefer days or weeks.
Frequently asked questions
Should I include the end date?
Turn it on when both the first and last day count, for example a hotel booking counted in days, a vacation or a project that runs from Monday to Friday inclusive. Leave it off for “how many days until” questions.
Are public holidays excluded from business days?
Not yet. Business days count Monday to Friday only. Subtract any public holidays in your country manually.
Does it account for leap years?
Yes. Every calendar day is counted, including February 29 in leap years.