What this calculator does
The gap between two dates is useful for project plans, contract terms, delivery windows and leave calculations. Calendar days and business days give different answers.
This calculator compares a start and end date and shows calendar days, business days, weekend days, weeks and months. You can choose whether the end date counts.
Date difference
Days = end date − start date (+1 optional) Business days exclude Saturdays and Sundays. Public holidays are not detected automatically and must be subtracted separately.
How this calculator works
- 01
Pick start and end dates
The end date must fall after the start date.
- 02
Choose end-date handling
Include or exclude the final day depending on your convention.
- 03
Review business days
Compare calendar days, weekdays and the approximate duration in weeks and months.
Frequently asked questions
Are public holidays included?
No. Only weekends are removed. Public holidays vary by country and region, so subtract them manually for precise planning.
Why does including the end date add one day?
Including the end date counts both boundary days. From 1 to 3 January, inclusive, is three days rather than two.
Are month totals exact?
Months and years use average lengths. For contracts and deadlines, the exact day count is more reliable.
Data basis: 2026 · Annual constants live in structured JSON files and are updated once a year.
Results are unverified model calculations and do not replace tax, legal or financial advice.