Last reviewed: 2026-05-23
BA II Plus mistakes CFA Level I candidates should catch
If your CFA Level I calculator answer is wrong but your formula is right, check the calculator state before you relearn the topic. The most common BA II Plus-style mistakes are payment mode, P/Y and C/Y, stale registers, stale cash flows, sign convention, and arithmetic mode.
Open the BA II Plus-style calculator
Read all twelve calculator mistakes
The six BA II Plus-style checks
| Rule | Check | Why it matters |
|---|---|---|
| M1 | BGN mode | An annuity due is one period ahead of an ordinary annuity. |
| M2 | P/Y and C/Y | Monthly settings can distort annual CFA inputs. |
| M3 | TVM registers | Old N, I/Y, PV, PMT, or FV values can leak into the next problem. |
| M4 | Sign convention | PV, PMT, and FV need consistent cash-flow direction. |
| M5 | Cash-flow worksheet | Old CF entries can remain in the list. |
| M6 | Chn/AOS arithmetic mode | Mixed arithmetic chains can evaluate differently. |
Fast Level I setup checklist
- Clear TVM registers before a new TVM problem.
- Confirm END mode unless the prompt says payments occur at the beginning of the period.
- Confirm
P/Y = 1andC/Y = 1for annual inputs unless the question gives a different compounding setup. - Keep cash outflows negative and inflows positive.
- Clear the cash-flow worksheet before a new NPV or IRR problem.
- Use the same arithmetic mode consistently while practicing.
Read the BA II Plus setup guide
Example: BGN mode changes an annuity answer
Prompt: Find the future value of three annual payments of 100 at 10%, assuming payments occur at the end of each year.
| State | Result |
|---|---|
| END mode | 331.00 |
| BGN mode | 364.10 |
The formula knowledge is the same. The device state changed the timing.
Example: P/Y and C/Y can hide in plain sight
Level I problems often give annual rates and annual periods. If your calculator is still set to P/Y = 12, your TVM answer may reflect a monthly payment setup rather than the annual setup in the prompt.
Example: stale TVM and cash-flow registers
The calculator does not know that the next question is unrelated to the last one. If old TVM values or old cash-flow entries remain in memory, the result can look precise while being built on the wrong inputs.
Read how to clear TVM registers
Read how to enter uneven cash flows
How Charterly helps
Charterly computes the answer and surfaces non-blocking warnings for these device-state risks. The warning does not stop the calculator. It tells you which habit to check while the result is still visible.
Frequently asked questions
What is the first thing to check when a BA II Plus answer looks wrong? Check BGN/END mode, then P/Y and C/Y, then clear stale TVM or CF entries.
Should CFA Level I candidates leave P/Y and C/Y at 1? For annual TVM prompts, P/Y = 1 and C/Y = 1 is the clean default. Change it only when the prompt gives a different payment or compounding setup.
Does Charterly block the answer when it sees a mistake risk? No. It computes the answer and surfaces a warning.
Is this page only for Level I? The examples are Level I-friendly, but the habits also matter in calculator-heavy Level II work.
Where is the broader mistake list? Use the CFA calculator mistakes page for both BA II Plus-style and HP 12C-style rules.