Percent change, margin, break-even and interest conversion

12.1Find a percent change (%CH)#

Press 2ND%CH1. The lines are OLD, NEW, %CH and #PD (number of periods, 1 at the start). Enter any two of OLD, NEW and %CH (with #PD) and compute the third.

$$\%CH = \frac{NEW-OLD}{OLD}\times 100$$

Example 12.1

Price rose from 100 to 125

1. Enter OLD and NEW, then compute %CH.

   2ND%CH1100ENTER↓125ENTER↓CPT

Example 12.2

Price fell from 100 to 80

1. The change is negative.

   2ND%CH1100ENTER↓80ENTER↓CPT

Example 12.3

Grow 1,000 at 5% over 10 periods

1. Enter OLD, %CH and #PD, then compute NEW.

   2ND%CH11000ENTER↓↓5ENTER↓10ENTER↑↑CPT

See also Percent change between two numbers

12.2Find a profit margin (PROFIT)#

Press 2NDPROFIT2. Lines are CST (cost), SEL (selling price) and MAR (margin in percent of the selling price). Enter two and compute the third.

$$MAR=\frac{SEL-CST}{SEL}\times 100$$

Example 12.4

Margin from cost and price

1. Cost 100, selling price 125.

   2NDPROFIT2100ENTER↓125ENTER↓CPT

Example 12.5

Selling price from cost and margin

1. Cost 100, margin 20%: go to SEL and compute.

   2NDPROFIT2100ENTER↓↓20ENTER↑CPT

See also Profit margin and markup

12.3Find a break-even point (BRKEVN)#

Press 2NDBRKEVN3. Lines are FC (fixed costs), VC (variable cost per unit), P (price per unit), PFT (profit) and Q (quantity). Enter four and compute the fifth. With PFT = 0, Q is the break-even quantity.

$$Q=\frac{FC+PFT}{P-VC}$$

Example 12.6

Break-even quantity

1. Fixed costs 3,000, variable cost 15, price 20, profit 0.

   2NDBRKEVN33000ENTER↓15ENTER↓20ENTER↓0ENTER↓0ENTERCPT

Example 12.7

Profit at 1,000 units

1. Enter Q = 1,000, then compute PFT.

   2NDBRKEVN33000ENTER↓15ENTER↓20ENTER↓0ENTER↓1000ENTER↑CPT

See also Break-even point

12.4Convert nominal and effective interest (ICONV)#

Press 2NDICONV6. Lines are NOM (nominal annual rate), EFF (effective annual rate) and C/Y (compounding periods per year). Enter two and compute the third.

$$EFF=\left(1+\frac{NOM}{100\cdot C/Y}\right)^{C/Y}-1$$

Example 12.8

Effective rate for 12% compounded monthly

1. NOM 12, C/Y 12, compute EFF.

   2NDICONV612ENTER↓↓12ENTER↑CPT

Example 12.9

Nominal rate for a 10% effective rate

1. Show nine decimals, enter EFF 10 and C/Y 4, compute NOM.

   2NDFORMAT.9ENTER2NDQUITCPT2NDICONV6↓10ENTER↓4ENTER↑↑CPT

See also Convert a nominal rate to an effective rateCompound interest

BA II Plus is a trademark of Texas Instruments Incorporated. Trident Calculator is an independent product by South View Studios and is not affiliated with, sponsored by or endorsed by Texas Instruments. The name is used only to describe the kind of calculator this model resembles; Trident's names, keys, display, fonts and software are its own clean-room design.