Finance Date Calculator
Days between dates (actual or 30/360), date ± N days, and weekday — BA II Plus DATE worksheet.
Educational estimate only — not investment, lending, or financial advice. Confirm figures with statements or a qualified professional before you act.
About this tool
Two date tools for finance work. Count the days between two dates using actual days or the 30/360 convention, or add and subtract days to see the resulting date and its weekday.
How to use
How it works
Actual counting uses the real calendar. The 30/360 convention treats every month as 30 days, which is common for bond and loan interest, and so a full calendar year is exactly 360 days. When adding days, the result also shows the weekday of the start and end dates.
actual days = end − start 30/360 days = 360 × Δyears + 30 × Δmonths + Δdays (with end-of-month adjustments)
Worked example
A full calendar year, two ways
- Input
- Start 2024-01-01; end 2024-12-31
- Output
- Actual 365 days; 30/360 360 days
- Walkthrough
- 2024 is a leap year with 366 days, and 1 Jan to 31 Dec is 365 days elapsed. On 30/360, 11 months × 30 plus 30 days gives 360. Adding 90 days to Monday 1 January 2024 gives Sunday 31 March 2024.
Limitations
- Calendar days only; no business-day or holiday logic.
- Only two day-count options: actual and 30/360.
Questions
What is the 30/360 day count?
How many days are there between 1 Jan and 31 Dec 2024?
What is 90 days after 1 January 2024?
Can I subtract days?
Features
- Actual and 30/360 day counts
- Date plus or minus N days
- Weekday shown
- Runs in your browser
Related resources
Guides and videos from around the web—opens on YouTube or the publisher’s site.
Amortization
Khan Academy
Principal vs interest breakdown for schedules.
Watch on YouTubeIntroduction to bonds
Khan Academy
Coupon and yield basics for bond calculators.
Watch on YouTube
- Compound Interest
Math is Fun
Formulas for growth used by TVM and ICONV pages.
- Time value of money
Wikipedia
TVM equation background for financial calculator pages.