Free BMI & Calorie Calculator
Wondering where your weight stands, or how many calories you actually need each day? This free tool gives you both answers in seconds no sign-up, no email required.
The BMI calculator uses your height and weight to estimate whether you fall into the underweight, normal, overweight, or obese range. The calorie calculator uses the Mifflin-St Jeor equation the same formula most dietitians rely on to estimate your daily maintenance calories and a suggested protein, carb, and fat split based on your age, sex, weight, height, and activity level.
This tool provides general estimates for informational purposes only and is not a substitute for professional medical or nutritional advice. Consult a doctor or registered dietitian for personalized guidance.
How BMI and Calorie Calculations Work
Body Mass Index (BMI) is calculated by dividing your weight by the square of your height. It's a quick screening tool used worldwide by doctors and health organizations, though it doesn't account for muscle mass, bone density, or body composition so it's a useful starting point, not a complete picture of your health.
Your daily calorie needs are estimated using the Mifflin-St Jeor equation, which calculates your Basal Metabolic Rate (BMR) the calories your body burns at rest then multiplies it by an activity factor based on how much you move day to day. The result is your maintenance calories: roughly what you'd need to eat to keep your current weight steady.
Frequently Asked Questions
What is a healthy BMI range?
A BMI between 18.5 and 24.9 is generally considered a healthy range for most adults. Below 18.5 is classified as underweight, 25–29.9 as overweight, and 30 or above as obese.
Is BMI accurate for everyone?
BMI is a useful general screening tool, but it doesn't distinguish between muscle and fat. Athletes or very muscular individuals may show a higher BMI without carrying excess body fat. It's best used alongside other health indicators, not as a standalone diagnosis.
How accurate is the calorie calculator?
The Mifflin-St Jeor equation is considered one of the most reliable BMR formulas available and is widely used by dietitians. That said, it's still an estimate individual metabolism can vary based on genetics, muscle mass, and other factors.
Should I eat exactly the calorie number shown?
The number shown is your estimated maintenance calories what keeps your weight stable. If your goal is weight loss or gain, you'd typically adjust from that baseline, ideally with guidance from a doctor or registered dietitian.
Is this calculator free to use?
Yes, completely free with no sign-up or email required. Use it as often as you like to track changes over time.