Tools

Calculators

Every calculator shows the formula, the answer and the full working, so you learn the method rather than just getting a number.

Revenue

Price × quantity

Total revenue from selling a number of units at a price.

T R = P \times Q

Revenue − costs

Profit or loss after subtracting total costs from total revenue.

Profit = T R - T C

Gross, operating & net

Walk down an income statement and compute all three profit margins.

Margin = \frac{Profit}{Revenue} \times 100

Units to cover all costs

How many units you must sell to cover fixed and variable costs.

Q_{B E} = \frac{F C}{P - V C}

Gain ÷ cost

Percentage return on an investment, a common criterion for comparing options in FRQ 4: Business Decision.

R O I = \frac{Net return}{Cost of investment} \times 100

I = P·r·t

Interest that is paid only on the original principal.

I = P \times r \times t

Interest on interest

Growth of a lump sum when interest compounds.

A = P (1 + \frac{r}{n})^{n t}

Monthly payment & total interest

Monthly payment on an amortizing loan such as a car loan or mortgage, with a yearly schedule.

M = \frac{P \cdot i}{1 - ( 1 + i ) ^{- n}}

Deposits + compounding

Future balance from an initial deposit plus regular monthly deposits.

F V = P (1 + i)^{n} + P M T \cdot \frac{( 1 + i ) ^{n} - 1}{i}

Split take-home pay

Allocate monthly net income across categories (such as 50/30/20) and compare with planned spending.

Category target = Net income \times \frac{%}{100}

Value of the next-best choice

Compare alternatives and find the value of the next-best option you give up.

Opportunity cost = Value of the next-best alternative