Precision Health Suite

Calorie Calculator

Calculate how many calories you need per day based on your body stats, activity level, and weight management goal.

✓ Runs in your browser · Updated 2026-03-31
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Enter values and click Calculate Calories to see results

Calculate how many calories you need per day based on your body stats, activity level, and weight management goal.

Updated: 2026-03-31

How Calorie Needs Are Calculated

Your daily calorie requirement is based on your TDEE (Total Daily Energy Expenditure), which combines your BMR (Basal Metabolic Rate) with an activity multiplier. This calculator uses the Mifflin-St Jeor equation for BMR.

Maintenance: TDEE = BMR × Activity Factor

Weight Loss: TDEE − 500 kcal/day (≈0.45 kg/week loss)

Weight Gain: TDEE + 500 kcal/day (≈0.45 kg/week gain)

Understanding Calorie Deficit & Surplus

A calorie deficit means you consume fewer calories than you burn, leading to weight loss. A calorie surplus means you consume more than you burn, leading to weight gain. A deficit of 500 calories per day roughly translates to losing about 0.45 kg (1 pound) per week.

Protein Guidelines

Protein intake is important for preserving muscle during weight loss or building muscle during weight gain. A general guideline is 1.6–2.2 g of protein per kg of body weight for active individuals.

Tips for Managing Calories

Track your food intake consistently, prioritise whole foods, maintain adequate protein, and adjust your intake every 2–4 weeks based on progress. Avoid going below 1200 kcal/day (women) or 1500 kcal/day (men) without medical supervision.

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Frequently Asked Questions

How many calories should I eat to lose weight?

A safe calorie deficit is 300-500 calories below your maintenance level. This calculator shows maintenance, mild loss (-250), moderate loss (-500), and aggressive loss (-750) targets.

Are all calories equal?

While total calories determine weight change, the source matters for health. Prioritise protein (1.6-2.2 g/kg), adequate fibre, and micronutrient-rich foods over empty calories.