Product or output refers to the volume of goods produced by a firm or an industry during a specified period of time. The concept of product can be considered from three different angles – Total Product, Marginal Product, Average Product.

### Total Product (TP)

Total Product (TP) refers to the total quantity of goods produced by a firm during a given period of time with the given number of inputs. For example, if 10 labourers produce 60 kg of rice, then the TP is 60 kg. In the short run a firm can expand TP by increasing only the variable factors. However, in the long run, TP can be raised by increasing both fixed and variable factors. TP is also known as ‘Total Physical Product (TPP)’ or ‘Total Return’ or ‘Total Output’.

### Marginal Product (MP)

Marginal Product (MP) refers to the addition to TP, when one more unit variable factor is employed. MP can be written as,

MP_{n} = TP_{n} – TP_{n-1}

Where,

MP_{n} = MP of n^{th} unit of variable factor

TP_{n} = TP of n units of variable factor

TP_{n-1} = TP of (n-1) units of variable factor

n = number of units of variable factor

For example, if 10 labourers make 60 kg of rice and 11 labourers make 67 kg of rice, then MP of the 11th labour will be

MP_{11} = TP_{11} – TP_{10}

MP_{11} = 67-60 = 7 kg

We now know that MP is the change in TP when one more unit of variable factor is employed. However, when change in variable factor is greater than one unit, then MP can be calculated as,

MP = Change in TP/ Change in units of Variable Factor

MP = ΔTP/Δn

Suppose 2 labourers produce 60 units and 5 labourers produce 90 units, then MP will be,

MP = 90-60/5-2 = 30/3 = 10 units

### Average Product (AP)

Average product (AP) refers to output per unit variable input. For example, if TP is 60 kg of rice, produced by 10 labourers (variable input), then AP will be 60/10 = 6 kg.

AP is obtained by dividing TP by number of units of variable output. AP can be written as,

AP = TP/Units of variable factor (n)