BA II Plus Date Worksheet: Days Between Dates, Maturity Dates and More

In this tutorial

Opening the worksheet and the MM.DDYY date format
Example 1: days between two known dates
Example 2: finding a maturity date from a day count
Actual-day vs 360-day counting
US and European date display formats
Where date math matters: bonds, notes and settlement

Opening the Date worksheet

Press [2nd] then [DATE] (above the number 1). You will see three fields:

DT1 — the first date, entered as MM.DDYY. October 15, 2025 is 10.1525; March 10, 2026 is 3.1026.
DT2 — the second date, in the same format.
DBD — the number of days between DT1 and DT2, computed with [CPT].

The calculator counts days from DT1 to DT2, including the start day and excluding the end day. If DT2 is earlier than DT1, DBD is negative — the magnitude is what most questions want.

Example 1: days between June 1 and November 15, 2025

A note is issued on June 1, 2025 and matures on November 15, 2025. How many days does the interest accrue?

Press [2nd] then [DATE].
Press [2nd] then [CLR WORK].
At DT1, enter 6.0125 (June 1, 2025), press [ENTER].
Scroll to DT2, enter 11.1525 (November 15, 2025), press [ENTER].
Scroll to DBD and press [CPT].

The display reads 167. Count it by hand to confirm: June 1 → June 30 is 29 days, July 31, August 31, September 30, October 31, then November 1–15 is 15 more — 29 + 31 + 31 + 30 + 31 + 15 = 167.

Example 2: find a maturity date from a day count

A 90-day commercial paper is dated March 10, 2026. On what date does it mature? Here you enter the day count directly at DT2 and let the calculator produce the date.

Press [2nd] then [DATE].
Press [2nd] then [CLR WORK].
At DT1, enter 3.1026 (March 10, 2026), press [ENTER].
Scroll to DT2, enter 90 (the number of days), press [ENTER].
Scroll to DBD and press [CPT].

The DT2 field now displays 6.0826 — June 8, 2026. Check: March 10 + 21 days reaches March 31, +30 days reaches April 30, +31 days reaches May 31 — that is 82 days, and 8 more days lands on June 8. The worksheet skipped nothing, including the fact that 2026 is not a leap year.

Actual-day vs 360-day counting

Some instruments use a 360-day "banker's year" convention. The Date worksheet supports both:

With the worksheet open, scroll to DBD.
If the display shows ACT, press [2nd] then [SET] to switch to 360 day-count mode.
Compute DBD again and compare — the 360-day answer differs from the actual-day answer whenever the date span crosses month boundaries unevenly.

Exam questions state the convention ("using a 30/360 basis"); make the worksheet match before trusting the number.

US vs European date display

By default the calculator shows US order (month-day-year: 10-15-2025) but enters dates as MM.DDYY either way. To switch the display to European day-month order:

Press [2nd] then [FORMAT].
Scroll until you see the date line, e.g. US 12-31-1990.
Press [2nd] then [SET] to toggle to EUR 31-12-1990.

The display format is cosmetic — it does not change how you enter MM.DDYY values. Keep whichever you read more reliably; the BOND worksheet reads the same setting, so settle on one format before a fixed-income problem.

Where date math matters

Bond settlement. The bond YTM tutorial uses actual settlement and maturity dates in the Bond worksheet; day counts drive the accrued-interest part.
Notes and commercial paper. Interest accrues on the actual days between issue and maturity — exactly what DBD gives.
Loan schedules. When payments are tied to calendar dates, count days first, then apply the AMORT worksheet.

Common mistakes and error traps

Wrong MM.DDYY syntax. 6.0125 means June 1, 2025 — the month has one digit, the day always two, the year two. 6.125 would be read as June 12, 2025.
Forgetting the leading zero for single-digit days. March 5 is 3.0526, not 3.526.
Negative DBD. If the answer is negative, swap DT1 and DT2 — the magnitude is usually the requested day count.
Mixing day-count conventions. An ACT answer used where a 30/360 basis was specified is simply wrong.
Old stored dates. Clear with [2nd] then [CLR WORK] before entering a new pair.