One more way.
while True:
try:
wd = int(input('How wide would you like your letter to be? (5-20)' + ': '))
if wd <=20 and wd >= 5:
print ('You have answered: %s' % wd)
break
else:
print('please enter a value between(5-20)')
except (ValueError,NameError,SyntaxError):
print ("Oops! That was no valid number. Try again...")