Date Calculator
Days between two dates (DBD) under the actual calendar or the US 30/360 NASD convention used for many bond and loan accruals.
Dates
Result
Worked example (T10): 2026-03-15 → 2026-12-31: ACT = 291 days; 30/360 (NASD) = 286 days.
BA II Plus keystrokes
Dates are entered as MM.DDYYYY.
- [2ND] [DATE]03.152026[ENTER]
- [↓]12.312026[ENTER]
- [↓][CPT]
Key map (same as the simulator): 2ND P/Y = P/Y worksheet · 2ND BGN = mode · 2ND CLR WORK = clear the open worksheet · 2ND CLR TVM = clear TVM.
Worked example — ACT vs 30/360 (T10)
2026-03-15 → 2026-12-31: actual days 291; 30/360 (NASD) counts 286 — D2 = 31 stays 31 because D1 = 15 < 30, so DBD = 30×9 + 16 = 286.
Frequently asked questions
What is the NASD adjustment exactly?
If D1 = 31 it becomes 30; if D2 = 31 and D1 ≥ 30 then D2 becomes 30. Then DBD = 360·ΔY + 30·ΔM + ΔD.
Which basis do bonds use?
US corporate and municipal bonds typically accrue on 30/360; Treasuries use ACT/ACT. The BOND worksheet on the calculator lets you toggle.