2. Introduction
In mathematics, a percentage is a number or ratio
that can be expressed as a fraction of 100. If we
have to calculate percent of a number, divide the
number by the whole and multiply by 100. Hence,
the percentage means, a part per hundred. The
word per cent means per 100. It is represented by
the symbol “%”.
Percentages have no dimension. Hence it is called a
dimensionless number. If we say, 50% of a
number, then it means 50 per cent of its whole.
To determine the percentage, we have to divide the
value by the total value and then multiply the
resultant by 100.
Percentage formula = (Value/Total value) × 100
3. The term "percent" is derived from the Latin per
centum, meaning "hundred" or "by the
hundred".
The sign for "percent" evolved by gradual contraction of
the Italian term per cento, meaning "for a hundred". The
"per" was often abbreviated as "p."—
eventually disappeared entirely. The "cento" was
contracted to two circles separated by a horizontal line, from which
the modern "%" symbol is derived.
4. Percentage increase
• The percent increase formula, which also can measure percent
decrease, is a measurement of how much a certain figure
changes over time. To calculate this number, you find the
difference between the original and current values, divide that
result by the original value and multiply it by 100 to convert it to
a percentage. Here's an outline of the percent increase formula:
• Percent increase = [(new value - original value) / original value]
x 100
5. • There's also a simplified version of this
formula. Using the simplified version
requires first calculating the increase,
which is subtracting the original value
from the new value in the longer formula.
Here's what using these formulas may
look like:
• Increase = new value - original value
• Percent increase = (increase / original
value) x 100
6. Percentage decrease
• Calculating percentage decreases can help determine the
effectiveness of money-saving measures, such as promotional
rates, and aid you in making comparisons. By following a few
simple steps, you can learn how to calculate percentage
decrease.
7. To calculate a percentage decrease, first work
out the difference (decrease) between the two
numbers you are comparing.
Decrease = Original Number − New Number
Decrease=Original Number−New Number
Next, divide the decrease by the original
number and multiply the answer by 100.
Percentage Decrease=( Original Number
Decrease)×100
The result expresses the change as a
percentage—i.e., the percentage change.
8. Example of Calculating Percentage
Change
As an example of calculating percentage change, consider Grace, who bought shares of a
stock at $35 per share on Jan. 1. On Feb. 1, the stock was worth $45.50 per share. By what
percentage did Grace’s share value increase?
To answer this question, first calculate the difference in price between the new and old
numbers.
$45.50 - $35 = $10.50 more. To work out the increase as a percentage, divide the increase
by the original (January) number:
10.5 / 35=0.3
Finally, to get the percentage, we multiply the answer by 100. This simply means moving
the decimal place two columns to the right.
0.3×100=30
Grace’s stock increased by 30%.
9. Percentages as decimals
To convert a percentage
to a decimal, divide by
100. So 25% is 25/100, or
0.25. To convert a
decimal to a percentage,
multiply by 100 (just
move the decimal point 2
places to the right). For
example, 0.065 = 6.5%
and 3.75 = 375%.
10. How Is Percentage Change Used in
Finance?
Percentage change is often used in finance to track the value
increase or decrease of a stock or large market indexes over time.
It is also used to compare the values of different currencies.
11. Companies also use
percentage change in
balance sheets to provide a
comparative view of assets
over different quarters or
years. And they use
percentage change in
quarterly reports to report
trends in their revenues
over the same quarter in
the prior year.
