You also need to make sure that you walk for at least 2 hours a week. You can find BMI calculators online by simply doing a search on Google or another search engine. People can't stay on their diet their whole lives.You also need to make sure that you walk for at least 2 hours a week. You can find BMI calculators online by simply doing a search on Google or another search engine. People can't stay on their diet their whole lives.