BMI Calculator1.py

# TODO List: GUI, Enabling user to type ft and inches whilst in imperial system

from datetime import datetime

name = raw_input('What is your name?: ')

gender = raw_input('What is your gender? Male, Female or Other: ').strip()
while gender.lower() not in ('male', 'female', 'other'):
    print('Error! Try again.')
    gender = raw_input('What is your gender? Male, Female or Other: ').strip()
    if gender.lower() not in ('male', 'female', 'other'): continue

format_DOB = raw_input('Enter your DOB in dd/mm/yyyy format: ')
DOB = datetime.strptime(format_DOB, '%d/%m/%Y')

measurement = raw_input('Do you wish to use the metric system or imperial system?: ').strip()
while measurement.lower() not in ('metric', 'imperial'):
    print('Error! Type metric or imperial only noob!!! Follow the instructions you pleb!')
    measurement = raw_input('Do you wish to use the metric system or imperial system?: ').strip()
    if measurement.lower() not in ('metric', 'imperial'): continue

if measurement.lower() == 'metric':
    height = float(input('Enter your height in meters: '))
    weight = int(input('Enter your weight in kilograms: '))
    bmi = weight / height ** 2

    if bmi <= 18.5:
        print('Hi %r, you are %r, your age is %r and your Body Mass Index is %r therefore you are underweight') % (name, gender, (datetime.today() - DOB).days/365, bmi)

    elif bmi > 18.5 and bmi < 25:
        print('Hi %r, you are %r, your age is %r and your Body Mass Index is %r therefore you have healthy weight') % (name, gender, (datetime.today() - DOB).days/365, bmi)

    elif bmi > 25 and bmi < 30:
        print('Hi %r, you are %r, your age is %r and your Body Mass Index is %r therefore you are overweight') % (name, gender, (datetime.today() - DOB).days/365, bmi)

    elif bmi > 30:
        print('Hi %r, you are %r, your is %r and your Body Mass Index is %r therefore you are obese') % (name, gender, (datetime.today() - DOB).days/365, bmi)

elif measurement.lower() == 'imperial':
    height = float(input('Enter your height in inches: '))
    weight = int(input('Enter your weight in pounds: '))
    bmi = (weight * 703) / height ** 2

    if bmi <= 18.5:
        print('Hi %r, you are %r, your age is %r and your Body Mass Index is %r therefore you are underweight') % (name, gender, (datetime.today() - DOB).days/365, bmi)

    elif bmi > 18.5 and bmi < 25:
        print('Hi %r, you are %r, you are %r, your age is %r and your Body Mass Index is %r therefore you have healthy weight') % (name, gender, (datetime.today() - DOB).days/365, bmi)

    elif bmi > 25 and bmi < 30:
        print('Hi %r, you are %r, your age is %r and your Body Mass Index is %r therefore you are overweight') % (name, gender, (datetime.today() - DOB).days/365, bmi)

    elif bmi > 30:
        print('Hi %r, you are %r, your age is %r and your Body Mass Index is %r therefore you are obese') % (name, gender, (datetime.today() - DOB).days/365, bmi)