Interest Conversion Calculator
EFF = (1 + NOM/(100·C/Y))^C/Y − 1: the effective annual rate of a nominal rate compounded C/Y times a year — the ICONV worksheet in form shape.
Interest conversion
Result
Worked example (T9): NOM=12, C/Y=12 → EFF = 12.68 (12.682503 at DEC=6).
BA II Plus keystrokes
- [2ND] [ICONV]12[ENTER]
- [↓][↓]12[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 — monthly compounding (T9)
NOM = 12%, C/Y = 12: EFF = 12.68% (12.682503 at six decimals) — the annual rate that is truly earned once monthly compounding is taken into account.
Frequently asked questions
Why is EFF above NOM?
Compounding more often than annually earns interest on interest within the year; with C/Y = 1, EFF equals NOM.
How do I go the other direction (EFF → NOM)?
On the simulator: enter EFF, ↓ to C/Y, and CPT on the NOM row. The guide shows the full keystrokes.
Which one do exam questions quote?
Read carefully: stated annual rates are usually nominal; “effective annual” or EAR always means the compounded rate.