# Calculate percentage from user Input in Python Last updated: Aug 26, 2022 Photo from Unsplash

## Calculate percentage from user Input in Python#

To calculate percentage from user input:

1. Convert the input values to floats.
2. Use the division `/` operator to divide one number by another.
3. Multiply the quotient by `100` to get the percentage.
4. The result shows what percent the first number is of the second.
main.py
```Copied!```# 👇️ if you need to format an input value to 1 or more decimal places
user_input = input('Type a percentage, e.g. 10: ')

result = f'{float(user_input) / 100:.1%}'

print(result)  # 👉️ 10.0%

# ----------------------------------------

# 👇️ make sure to convert input() result to float()

def is_what_percent_of(num_a, num_b):
return (num_a / num_b) * 100

print(is_what_percent_of(25, 75))  # 👉️ 33.33
print(is_what_percent_of(15, 93))  # 👉️ 16.12903..
print(round(is_what_percent_of(15, 93), 2))  # 👉️ 16.13

# --------------------------------------------------

def get_percentage_increase(num_a, num_b):
return ((num_a - num_b) / num_b) * 100

print(get_percentage_increase(60, 30))  # 👉️ 100.0
print(get_percentage_increase(40, 100))  # 👉️ -60.0

# --------------------------------------------------

def get_remainder(num_a, num_b):
return num_a % num_b

print(get_remainder(50, 15))  # 👉️ 5
print(get_remainder(50, 20))  # 👉️ 10
``````

The first example uses a formatted string literal to format an input value to 1 or more decimal places.

main.py
```Copied!```user_input = input('Type a percentage, e.g. 10: ')

result = f'{float(user_input) / 100:.1%}'
print(result)  # 👉️ 10.0%

result = f'{float(user_input) / 100:.2%}'
print(result)  # 👉️ 10.00%
``````
Formatted string literals (f-strings) let us include expressions inside of a string by prefixing the string with `f`.

Make sure to wrap expressions in curly braces - `{expression}`.

We are also able to use the format specification mini-language in expressions in f-strings.

main.py
```Copied!```my_float = 0.79

result_1 = f'{my_float:.1%}'
print(result_1)  # 👉️ 79.0%

result_2 = f'{my_float:.2%}'
print(result_2)  # 👉️ 79.00%
``````

If you need to calculate what percent one number is of another, divide one number by the other and multiply the result by `100`.

main.py
```Copied!```def is_what_percent_of(num_a, num_b):
return (num_a / num_b) * 100

num1 = float(input('Enter a number: '))  # 👉️ 25
num2 = float(input('Enter another number: '))  # 👉️ 75

result = is_what_percent_of(num1, num2)

print(result)  # 👉️ 33.33333333333333

print(round(result, 2))  # 👉️ 33.33
``````

Make sure to use the `float()` class to convert the input strings to floating-point numbers.

The `input()` function is guaranteed to return a string even if the user enters a number.

Use the `round()` function if you need to round the result to N decimal places.

The `round` function returns the number rounded to `ndigits` precision after the decimal point.

Note that if you try to divide by `0`, you'd get a `ZeroDivisionError`.

If you need to get the percentage increase from one number to another, use the following function.

main.py
```Copied!```def get_percentage_increase(num_a, num_b):
return ((num_a - num_b) / num_b) * 100

print(get_percentage_increase(60, 30))  # 👉️ 100.0
print(get_percentage_increase(40, 100))  # 👉️ -60.0
``````

The first example shows that the percentage increase from `60` to `30` is `100 %`.

And the second example shows that the percentage increase from `40` to `100` is `-60%`.

If you always need to get a positive number, use the `abs()` function.

main.py
```Copied!```def get_percentage_increase(num_a, num_b):
return abs((num_a - num_b) / num_b) * 100

print(get_percentage_increase(60, 30))  # 👉️ 100.0
print(get_percentage_increase(40, 100))  # 👉️ 60.0
``````

The abs function returns the absolute value of a number. In other words, if the number is positive, the number is returned, and if the number is negative, the negation of the number is returned.

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