Calorie Calculator (TDEE)

What is a calorie calculator?

A calorie calculator estimates how many calories your body burns in a full day — your Total Daily Energy Expenditure (TDEE). Eat roughly that many calories and your weight stays stable; eat less and you lose weight; eat more and you gain. It is the single most useful number for anyone planning a diet, because every weight goal starts from knowing your maintenance level.

This calculator works in two steps. First it estimates your Basal Metabolic Rate (BMR) — the calories you burn at complete rest — using the Mifflin-St Jeor equation, the formula most dietitians consider the most accurate for the general population. Then it multiplies BMR by an activity factor to get your TDEE.

How it works

Step 1 — BMR (Mifflin-St Jeor):

• Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
• Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

Step 2 — TDEE = BMR × activity factor:

The calculator also shows a mild weight-loss target: your TDEE minus 15%, a deficit most people can sustain without constant hunger.

How to use this calculator

1. Enter your age, gender, weight and height.
2. Pick the activity level that honestly matches your week — most desk workers are "light" at best.
3. Read three numbers: BMR (your at-rest burn), maintenance calories (eat this to stay the same), and mild-loss calories (eat this to slim down gradually).

Worked example

A 30-year-old man, 70 kg, 175 cm, exercising moderately (factor 1.55):

• BMR = 10×70 + 6.25×175 − 5×30 + 5 = 700 + 1,093.75 − 150 + 5 = 1,649 kcal
• Maintenance = 1,649 × 1.55 = 2,556 kcal/day
• Mild loss = 2,556 × 0.85 = 2,173 kcal/day

So about 2,550 kcal holds his weight steady, and about 2,170 kcal per day should trim roughly half a kilo per week.

Limitations and tips

• Estimates, not lab results: the equation is accurate within about 10% for most people, but muscle mass, hormones and medical conditions shift real burn. Treat the numbers as a starting point and adjust after 2–3 weeks of tracking.
• Be honest about activity: overestimating exercise is the most common mistake. When in doubt, pick one level lower.
• Do not crash-diet: very low intakes (well under BMR for long periods) slow metabolism and cost muscle. A 10–15% deficit is the sustainable path.
• Food quality counts too: calories decide weight change, but protein, fibre, vitamins and sleep decide how you look and feel while it happens.