Free Fitness Calculator: Track Your BMI, BMR, and Daily Calories
know your daily “Calorie Budget” & Eat What You Love
BMI & BMRCalculator
Understand your body composition, metabolic rate, and daily energy needs — powered by the Mifflin–St Jeor formula and WHO BMI classifications.
Your Details
All fields requiredReady to Calculate
Fill in your details on the left and press Calculate to see your full BMI & BMR analysis.
📊 Body Mass Index (BMI)
WHO Classification System—
🔥 Basal Metabolic Rate (BMR)
Mifflin–St Jeor Formula🎯 Personalised Recommendations
Based on your resultsBMI Classification Explained
Understanding the WHO's five BMI categories — what they mean, their health implications, and what to do about them.
May indicate nutritional deficiency. Associated with reduced immune function, bone density, and fertility. Consult a dietitian.
Associated with lowest risk for most chronic diseases. Maintain with balanced nutrition and regular activity. The target range.
Modestly increased risk for type 2 diabetes, hypertension, and cardiovascular disease. Moderate lifestyle changes recommended.
Significantly elevated health risk. Structured nutrition intervention and medical guidance strongly recommended.
High to very high disease risk. Medical supervision essential. Even 5–10% weight loss produces significant health improvements.
The Formulas Behind the Numbers
Transparency about the calculations — so you understand exactly what your results mean and how they're derived.
BMI is a simple screening tool developed in the early 19th century and adopted by the World Health Organisation to classify weight status relative to height. It is the most widely used population-level health screening metric globally.
Example: 80kg ÷ (1.75m)² = 80 ÷ 3.0625 = 26.1
Important limitation: BMI cannot distinguish between fat mass and muscle mass. A heavily muscled athlete may have a "Overweight" BMI while having very low body fat. Always interpret BMI alongside other measurements like waist circumference and body fat percentage.
BMR is the energy your body requires at complete rest to maintain basic physiological functions — breathing, circulation, cellular repair, and organ function. It accounts for 60–70% of total daily energy expenditure for most people.
Women: (10 × kg) + (6.25 × cm) − (5 × age) − 161
Mifflin & St Jeor, 1990 — validated in peer-reviewed research
We use the Mifflin–St Jeor equation (1990) over the older Harris–Benedict formula (1918) because it has been validated in multiple large studies and consistently outperforms older methods. Per the original research, accuracy is within ±10% for most healthy adults.
What These Numbers Don't Tell You
BMI and BMR are powerful screening tools — but they have important limitations every user should understand.
A 90kg athlete with 8% body fat and a 90kg sedentary person with 30% body fat will have identical BMIs. BMI is a population screening tool — not a precision body composition metric. If you're athletic, a DEXA scan or body fat measurement gives more useful data.
Two people with identical stats can have BMRs differing by 200–300 kcal/day due to genetics, thyroid function, muscle fibre composition, and gut microbiome. Use your BMR as a starting estimate and adjust based on 2–3 weeks of real-world tracking results.
Activity level multipliers are population averages. Most people overestimate their activity level, leading to a TDEE that's 10–20% higher than reality. Track your weight for 2–3 weeks and calibrate: if weight isn't changing at "maintenance," your true TDEE is likely lower.
Use Your Numbers to Build a Plan
Your BMI and BMR are the foundation. Here's where to go next to turn data into real results.
Go deeper — get your complete macro split (protein, carbs, fats) alongside your calorie target.
→The complete 12-week fat-loss plan — deficit, phases, meal plans, and weekly tracker.
→If your BMR shows room to eat more, use this plan to gain lean muscle with minimal fat.
→Build a full week of meals around your exact calorie and macro targets automatically.
→Once you know your calorie needs, learn how to split them between protein, carbs and fat.
→Share your BMI & BMR results with our team and get a fully personalised plan built around them.
→BMI & BMR FAQ
Know Your Numbers.
Now Build Your Plan.
Your BMI and BMR give you the data. Our free tools and consultation turn that data into a personalised nutrition strategy.
"Discipline is choosing between what you want now and what you want most."
Body Fat calculator
Your body fat is ......
🎯 Custom Gym Diet Plan Generator
Get a scientifically-backed, personalized nutrition plan tailored to your fitness goals. Built by nutrition experts for serious athletes.
Your Personalized Diet Plan is Ready!
Based on your profile, we've calculated the optimal nutrition strategy for your goals.
Macro Distribution
7-Day Meal Plan
Weekly Grocery List
💡 Pro Tips
⚠️ Common Mistakes to Avoid
Hydration & Supplement Guidance
💧 Hydration Protocol
Daily Target: 3.5 liters minimum
- • 500ml upon waking
- • 250-500ml with each meal
- • 1L during workout
- • Reduce intake 2h before bed
💊 Recommended Supplements
This diet plan is generated based on general nutritional guidelines and mathematical calculations. It is not intended as medical advice. Always consult with a qualified healthcare provider, registered dietitian, or physician before starting any new diet or exercise program, especially if you have pre-existing health conditions, are pregnant, nursing, or taking medications.