How do I print a '%' sign using string formatting?

The new Python 3 approach is to use format strings.

percent = 12
print("Percentage: {0} %\n".format(percent))
>>> Percentage: 12 %

This is also supported in Python > 2.6.

See the docs here: Python 3 and Python 2

To print the % sign you need to 'escape' it with another % sign:

percent = 12
print "Percentage: %s %%\n" % percent  # Note the double % sign
>>> Percentage: 12 %

EDIT

Nowadays in python3 a better (and more readable) approach is to use f-strings. Note that other solutions (shown below) do work as well:

$python3
>>> percent = 12
>>> print(f'Percentage: {percent}%') # f-string
Percentage: 12%
>>> print('Percentage: {0}%'.format(percent)) # str format method
Percentage: 12%
>>> print('Percentage: %s%%' % percent) # older format, we 'escape' the '%' character
Percentage: 12%

x = 0.25
y = -0.25
print("\nOriginal Number: ", x)
print("Formatted Number with percentage: "+"{:.2%}".format(x));
print("Original Number: ", y)
print("Formatted Number with percentage: "+"{:.2%}".format(y));
print()

Sample Output:

Original Number:  0.25                                                                                        
Formatted Number with percentage: 25.00%                                                                      
Original Number:  -0.25                                                                                       
Formatted Number with percentage: -25.00% 

Helps in proper formatting of percentage value

+++

Using ascii value of percentage - which is 37

print( '12' + str(chr(37)) )

Or use format() function, which is more elegant.

percent = 12
print "Percentage: {}%".format(percent)

4 years later edit

Now In Python3x print() requires parenthesis.

percent = 12
print ("Percentage: {}%".format(percent))