# Average Cost

The average cost is the average price of goods and services. When we have multiple products to sell or buy, of almost the same value, the average of these values will give the average cost price. It helps shopkeepers in the buying and selling process.

The average cost is the ratio of total of cost of all the products and total number of products. In Maths, we also term the average of any given set of data as mean of data. But in case of business, where profit and loss are the key features, average is said to be the right term.

## Average Cost Formula

The formula for calculating average cost is given by;

Average cost = Total cost of the units/Number of units

The average cost deals with the summation of arithmetic cost and the number of the quantity or the number of items given. The formula to calculate the average cost is given here.

X = ∑(xi)/n

Where xi is the sum of all costs and n is the number of items.

The symbol ‘∑’ (called sigma) is used to denote the summation.

### How to calculate average cost?

We have already discussed the formula to calculate average cost. Let us see some examples to find the average cost.

Example: Find the average cost of price of 10 bags whose prices are Rs.500, Rs.550, Rs. 450, Rs. 510, Rs. 520, Rs. 530, Rs. 540, Rs. 460, Rs. 470, Rs. 480 and Rs. 490.

Solution: Given, the cost price of 10 bags are:

Rs.500, Rs.550, Rs. 450, Rs. 510, Rs. 520, Rs. 530, Rs. 540, Rs. 460, Rs. 470, Rs. 480 and Rs. 490.

Hence, as per the average cost formula, we know;

Average = Sum of all the cost of bags/Total number of bags

A = (500+550+450+510+520+530+540+460+470+480+490)/10

A = 5500/100

A = 550

Therefore, Rs. 550 is the average cost of 10 bags.

## Average Cost and Marginal Cost

By the definition of average cost, we know it is the ratio of total cost and number of manufactured products. The total cost here is also termed as unit cost, which is equal to sum of fixed cost and variable cost.

Hence,

Average cost = Total cost/Number of units = (Fixed cost + Variable cost)/Number of units

Whereas, marginal cost is the cost incurred due to change in the total cost because of increase in number of products. Hence, it is the additional cost, because of manufacturing of extra products.

It is helpful for businesses to know whether it is beneficial to produce extra units of products or not. The marginal cost is given by;

MC = Change in total cost/Total units manufactured