How do you calculate the percentage of the difference between two numbers?

Question

For example: a candy bar cost $.60 last year; now it is $.65. The cost of a candy bar has gone up x percent. What is the formula for that calculation?

Answer 1

the expression of the percent increase is:

100* (the difference)/(the initial value)

in your example that would be

100 * (.05)/(.65) => 7.69%

The division is multiplied by 100 to make it into perent form.

That candybar has gone up about 8%.

Answer 2

The usual answer is to divide the difference (5 cents) by the original amount (60 cents).

The tricky thing about that is that if you go up by 5 percent and then down by 5 percent, you don't end up where you started.

Sometimes, in science, we measure a percent difference as the difference over the average of the two measurements. If the two measurements are close, this barely makes a difference.

I think the answer you want for general everyday use is the first one.

Answer 3

the formula would be the change in price divided by the old price. This gives you the percentage increase in the cost.
.65-.60/.60 = 8.3%

Answer 4

0.65/0.60= 1.08
1.08 x 100= 108%
thus, an 8% increase

or
the difference between 0.60 and 0.65 is 0.05

0.05/0.60= 0.08
0.08 x 100= 8 % increase

A percentage is really nothing more than a ratio based on 100 units of something. That way everyone knows that an 8 % increase means that if you paid 1.00 for something yesterday, you'll pay 1.08 for it today. Or, $0.60 yesterday means $0.65 today because of an 8% increase in cost.

Answer 5

The formula is

(amount of increase) over (original amount) = x over 100

Answer 6

(old value-new value)/old value

Multiply this by 100 to make it a percent

In other words, you calculate the difference, and find out what percent of the old value that difference is.