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How to use the keypad and the forms
The calculator opens on the Keypad tab. Click the keys, or click the calculator body and type: digits, + - * /, Enter, Backspace (the → key), Esc (CE|C) and the arrow keys. Second functions work as on the device: press 2ND, then the key under the green label. Beside the keypad you see the stored values, every key you pressed, and practice drills that replay a worked problem one key at a time.
The other six tabs are plain forms for anyone who wants a TVM or NPV answer rather than a key sequence. Each one solves as you type, shows the formula with your numbers, and lists the BA II Plus keys for the same problem, with a button that presses them on the keypad.
| Tab | What it solves |
|---|---|
| TVM | Any one of N, I/Y, PV, PMT and FV, with P/Y, C/Y and END or BGN |
| Cash flow | NPV, IRR (every root), MIRR, NFV, payback and discounted payback; dated flows for XIRR and XNPV |
| Amortization | Payment, full schedule, yearly totals, extra payments, and BAL, PRN and INT for payments P1 to P2 |
| Bond | Clean price or yield, accrued interest and dirty price; actual/actual or 30/360; 1 or 2 coupons a year |
| Depreciation | SL, SYD, DB and DBX schedules, with a part first year |
| Dates | Days between two dates (actual and 30/360), or a date plus a number of days |
Every tab keeps its inputs in the address bar, so a copied link opens the same problem. You can also write one yourself:
| Link ending | Opens |
|---|---|
?n=360&iy=6.5&pv=300000&pmt=&fv=0&py=12 | The TVM form; the empty value (here pmt) is solved. Add cy=4 or bgn=1 if needed |
?tab=cf&cf=-50000,12000x3,18000x2,9000&i=9 | Cash flows; 12000x3 means 12,000 three times in a row |
?tab=bond&sdt=2026-10-13&rdt=2034-06-15&cpn=5.5&yld=6.2&dc=act | A bond price; send pri= instead of yld= to solve the yield |
?keys=2ND,P/Y,12,ENTER,2ND,QUIT | The keypad with those keys already pressed |
The other tabs follow the same pattern: tab=amort with pv, iy, n, py, extra, p1, p2; tab=depr with m, cst, sal, lif, m01; and tab=date with d1 and d2.
The worksheet model: ENTER, CPT and clearing
The BA II Plus does not take typed formulas. It stores numbers in worksheets, and each worksheet solves for whichever variable you ask it to compute. There are two kinds.
- The TVM keys (N, I/Y, PV, PMT, FV) sit on the keypad itself. Type a number and press the key to store it; press CPT and then the key to compute it.
- Prompted worksheets (CF, NPV, IRR, AMORT, BOND, DEPR, DATE, ICONV, Δ%, PROFIT, BRKEVN, DATA, STAT, MEM and FORMAT) show one variable at a time. The arrows move between variables, ENTER stores the number you typed, CPT computes the variable on screen, and 2ND SET cycles a setting such as END and BGN or ACT and 360. 2ND QUIT returns to the standard mode.
A number you type is not stored until you press ENTER (or a TVM key). The display marks a stored value with a small triangle and a computed one with an asterisk, so you always know which is which. Values stay until you clear them, and stale values cause more wrong answers than anything else:
| Keys | Clears |
|---|---|
2ND CLR TVM | N, I/Y, PV, PMT and FV, but not P/Y, C/Y or BGN |
2ND CLR WORK | The prompted worksheet on screen, for example every cash flow in CF |
2ND RESET ENTER | Everything: worksheets, memories, P/Y back to 1, END, 2 decimals and chain mode |
CE|C | The number being typed, an error message, or an unfinished calculation |
The formulas behind the worksheets
The TVM worksheet solves one equation. With i the interest rate per payment period, and G = 1 for END payments or 1 + i for BGN:
PV + PMT × G × (1 − (1 + i)^−N) ÷ i + FV × (1 + i)^−N = 0
I/Y is a yearly nominal rate in percent. The rate per period is i = (1 + I/Y ÷ (100 × C/Y))^(C/Y ÷ P/Y) − 1, which reduces to I/Y ÷ (100 × P/Y) when C/Y equals P/Y. N, PV, PMT and FV each have a closed form. I/Y does not, so the tool scans rates from −99.99% to above 100,000% per period for sign changes and narrows each one with Brent's method. When several rates fit, the form lists them all.
NPV discounts each cash flow to time 0: NPV = CFo + Σ Ct ÷ (1 + I/100)^t, where a flow with frequency F counts as F equal flows in a row. IRR is the rate that makes NPV zero. Every change of sign in the cash flows allows one more IRR: the flows −100, +230, −132 change sign twice and have two IRRs, 10% and 20%. The device shows the one closest to zero; the cash flow tab shows both. With no sign change at all, the device reports Error 5.
The bond worksheet uses the formulas from Standard Securities Calculation Methods, which the BA II Plus guidebook cites. With M coupons a year, a coupon C = CPN ÷ M per 100 of face value, N coupons still to come, A days since the last coupon, E days in the coupon period and DSC days to the next coupon:
PRI = RV ÷ (1 + Y/M)^(N − 1 + DSC/E) + Σ C ÷ (1 + Y/M)^(K − 1 + DSC/E) − C × A ÷ E
The last term is the accrued interest AI. PRI is the clean price, and the buyer pays PRI + AI. With one coupon period or less to go, the worksheet switches to a simple-interest version of the same formula.
Three worked examples with key sequences
1. A home loan payment, then the first year's interest
A 350,000 loan at 6.75% a year, repaid monthly over 25 years. Monthly payments mean P/Y = 12, so N = 25 × 12 = 300 and i = 6.75 ÷ 1200 = 0.005625.
2ND CLR TVM, 2ND P/Y 12 ENTER, 2ND QUIT, 25 2ND xP/Y N, 6.75 I/Y, 350000 PV, 0 FV, CPT PMT
The display shows PMT = −2,418.19, negative because you pay it out. Then 2ND AMORT 1 ENTER ↓ 12 ENTER ↓ ↓ ↓ steps through the first year: BAL 344,436.70, PRN −5,563.30 and INT −23,454.98. Almost 81% of the first year's payments goes to interest. Over all 300 payments the interest totals 375,457.15, more than the loan itself.
2. NPV and IRR with uneven cash flows
A project costs 50,000 today and returns 12,000 a year for 3 years, 18,000 a year for the next 2 years and 9,000 in year 6. The cost of capital is 9%. Equal flows in a row go in once, with a frequency F:
| Flow | Amount | F | Keys |
|---|---|---|---|
| CFo | −50,000 | CF 2ND CLR WORK 50000 +|- ENTER | |
| C01 | 12,000 | 3 | ↓ 12000 ENTER ↓ 3 ENTER |
| C02 | 18,000 | 2 | ↓ 18000 ENTER ↓ 2 ENTER |
| C03 | 9,000 | 1 | ↓ 9000 ENTER |
Then NPV 9 ENTER ↓ CPT gives NPV = 10,192.36, and IRR CPT gives IRR = 15.38%. Both say the same thing: the project earns more than the 9% it costs. The cash flow tab adds what the standard BA II Plus lacks: a MIRR of 12.42% with reinvestment at 9%, payback after 3.78 years and discounted payback after 4.59 years.
3. A bond's price and accrued interest
A 5.5% semiannual bond maturing on 15 June 2034, bought for settlement on 13 October 2026 and priced to yield 6.2%, with actual/actual day counts. Dates go in as mm.ddyy, so 13 October 2026 is 10.1326.
2ND BOND 2ND CLR WORK 10.1326 ENTER ↓ 5.5 ENTER ↓ 6.1534 ENTER ↓ ↓ ↓ ↓ 6.2 ENTER ↓ CPT ↓
The last coupon was paid on 15 June 2026 and the next falls due on 15 December 2026, so A = 120 of E = 183 days have passed and 16 coupons remain. The result is PRI = 95.77 per 100 of face value and AI = 1.80 (2.75 × 120 ÷ 183). For a 10,000 bond you pay 9,757.09 in total. The price sits below 100 because the 5.5% coupon is below the 6.2% the market wants.
Five traps that cost marks
- P/Y left over from the last problem. P/Y stays set until you change it. A 10-year annual annuity of 20,000 at 10% is worth 122,891.34 with P/Y = 1, but 191,130.80 if P/Y is still 12, because the calculator then reads N = 10 as ten months. Check P/Y before every TVM problem.
- The sign convention. Money you pay out is negative and money you receive is positive. Store a 75,000 loan and a 425.84 payment both as positive numbers and CPT I/Y returns Error 5: no rate can balance two inflows.
- BGN left on. The BGN indicator means payments at the start of each period. The same annuity is worth 135,180.48 in BGN mode, 12,289.14 more. Switch back with
2ND BGN 2ND SET 2ND QUIT. - Chain or AOS. The device comes set to chain mode, which works strictly left to right:
3 + 2 × 4 =gives 20. In AOS mode (2ND FORMAT, ↓ four times, 2ND SET) it gives 11, as in algebra. This calculator also starts in chain mode, so use brackets when the order matters. - C/Y is not always P/Y. Entering P/Y copies the same number into C/Y. A 100,000 loan over 120 monthly payments at 6% compounded quarterly needs C/Y = 4: the payment is 1,108.71, not the 1,110.21 you get with C/Y = 12.
Embed the BA II Plus Style Calculator on your website
Teachers, bloggers and course sites can add this tool to any web page for free. Paste the code below into an HTML or embed block (WordPress, Google Sites, Canvas, Moodle, Blogger, Wix). It loads the same tool you see above, without our menus or ads. Please keep the credit line under the frame. Sizes, a live preview and step-by-step guides for each platform are on the calculator widget page.
Frequently asked questions
Can I use this calculator in the CFA exam?
No. It is for practice. The CFA Institute allows only physical calculators in the exam room: the BA II Plus (including the Professional) and the HP 12C models. Practising here with the same keys builds the habits you take into the exam.
Is WideMath connected to Texas Instruments?
No. WideMath is an independent site. This BA II Plus style calculator is our own design that follows the device's key order and labels, and its maths was written from the formulas in the public guidebook. BA II Plus is a trademark of Texas Instruments.
Why does my IRR or I/Y show Error 5?
Error 5 means no solution exists: every cash flow has the same sign. Enter money you pay out as a negative number (type it, then press +|-) and money you receive as a positive one, then compute again.
How do I clear the calculator before a new problem?
Press 2ND CLR TVM for the five TVM values, 2ND CLR WORK inside a worksheet such as CF or BOND, or 2ND RESET ENTER for everything. P/Y, C/Y and BGN survive CLR TVM, so check them on their own.
What is the difference between P/Y and C/Y?
P/Y is payments per year and C/Y is compounding periods per year. Entering P/Y sets C/Y to the same value, which suits most loans. Change C/Y only when the compounding differs, such as monthly payments on a rate compounded quarterly.
Does it calculate MIRR, payback and XIRR?
Yes, in the Cash flow tab. MIRR, NFV and payback follow the definitions of the BA II Plus Professional. XIRR handles dated cash flows using actual days divided by 365, like a spreadsheet; the BA II Plus itself has no dated cash flow worksheet.