Daily Calorie Calculator
Find your personalised daily calorie target for weight loss, maintenance, or muscle gain — based on your age, body stats, and activity level.
Your Calorie Targets
BMR: 1,709 kcal/day
Each 500 kcal daily deficit/surplus ≈ 0.5 kg/week change in body weight. Results are estimates based on Mifflin-St Jeor formula.
How Many Calories Do You Need Per Day?
Your daily calorie needs are not a one-size-fits-all number. They depend on your age, sex, height, weight, and especially your physical activity level. This calorie calculator uses the Mifflin-St Jeor equation — the gold standard for BMR estimation — combined with an activity multiplier to give you your Total Daily Energy Expenditure (TDEE). From there, it shows you six calorie targets covering the full range from extreme weight loss to active weight gain.
All calculations run instantly in your browser. No data is ever uploaded or stored — making this a completely private tool for personal nutrition planning.
How to Calculate Your Daily Calories Online
- Select Metric or Imperial — choose your preferred unit system using the toggle.
- Choose your biological sex — the Mifflin-St Jeor formula applies different constants for male and female.
- Enter your age — use the number input or slider; age affects your BMR calculation significantly.
- Enter height and weight — type values or drag the sliders to your measurements.
- Choose your activity level — select the button that best represents your average week. Be honest — most people overestimate their activity.
- Read your targets — the result panel shows your TDEE and six goal-specific calorie targets, colour-coded by goal type.
How the Calorie Calculator Works Technically
The tool implements the Mifflin-St Jeor equation for BMR, then multiplies by a Physical Activity Level (PAL) factor to derive TDEE. Each of the six goal rows adds or subtracts a fixed calorie delta from TDEE, floored at 1,000 kcal to prevent physiologically dangerous targets from being shown.
BMR (female) = (10 × kg) + (6.25 × cm) − (5 × age) − 161
TDEE = BMR × PAL factor (1.2 – 1.9)
Goal target = max(1000, TDEE + delta)
The tool is powered by React useState and useMemo hooks — results recalculate only when inputs change, keeping the interface snappy even on low-powered mobile devices.
Understanding Your TDEE — 6 Practical Use Cases
- Sustainable fat loss: Use the Weight Loss row (TDEE − 500 kcal) for a safe 0.5 kg/week deficit that preserves muscle when combined with adequate protein intake.
- Lean muscle building: The Mild Gain row (TDEE + 250 kcal) supports muscle protein synthesis with minimal fat accumulation — ideal for beginners and intermediates in resistance training.
- Weight maintenance: Eating at your Maintain row (TDEE) keeps weight stable. Pair with our BMR Calculator to cross-check your result using both tools.
- Medical weight loss programmes: The Extreme Loss row (TDEE − 1000 kcal) is shown for reference; this level should only be used under medical supervision.
- Post-competition recovery: After a cutting phase, gradually increase calories back to TDEE over 4–8 weeks to restore metabolic rate before the next training cycle.
- Meal prep planning: Use your daily calorie target alongside our Macro Calculator to plan protein, carbohydrate, and fat intake per meal.
Choosing the Right Activity Level
The activity multiplier is the most variable component of TDEE — and the one most commonly misjudged. A sedentary office worker who exercises three times per week is Lightly Active (1.375), not Moderately Active. Athletes training twice a day may qualify as Extra Active (1.9). Overestimating activity leads to a higher TDEE estimate, which produces a calorie target that is too high and can stall or prevent fat loss. When in doubt, start with a lower activity level and adjust upward based on real-world results over 3–4 weeks.
Calories Are a Guide, Not a Law
Despite the precision of the numbers shown, calorie counting has inherent limitations. Food labels can have up to 20% error under FDA guidelines. Cooking changes caloric content. Individual gut microbiome differences affect absorption rates. Use your calorie target as a directional guide and adjust by 100–200 kcal based on actual weight trends over multi-week periods rather than daily fluctuations.
The Role of Protein in Calorie Planning
Regardless of your calorie target, protein intake is critical for body composition outcomes. Protein has the highest thermic effect of all macronutrients — 20–30% of protein calories are burned during digestion. It also preserves muscle during a calorie deficit and promotes satiety, making it easier to adhere to your target. Most evidence supports 1.6–2.2 grams of protein per kilogram of body weight for individuals seeking to preserve or build muscle. Use our Macro Calculator alongside this tool to set your precise protein, carbohydrate, and fat targets.
Privacy and Security
The Calorie Calculator runs entirely in your browser using the Mifflin-St Jeor formula in JavaScript — no API, no server, no data upload. Your age, height, weight, activity level, and calorie targets never leave your device. This is safe for personal nutrition planning, clinical weight management data, eating disorder recovery plans, and sensitive dietary health information.
✓Verified by ToollyX Team · Last updated June 2026
Frequently Asked Questions
Disclaimer: Calorie targets are estimates based on the Mifflin-St Jeor formula. Individual metabolic rates vary. Consult a registered dietitian before making major dietary changes.