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Calorie & Macro Calculator
Set a goal and a weekly rate to get a daily calorie target with your deficit or surplus, then split it into protein, carbs and fat for each meal.
Not medical advice. Individual energy needs vary. Results are estimates to help you plan.
How the calorie target is worked out
- BMR (Mifflin-St Jeor)10 × kg + 6.25 × cm − 5 × age + 5 (men) or − 161 (women)
- Maintenance (TDEE)BMR × 1.2 / 1.375 / 1.55 / 1.725 / 1.9 by activity
- Daily deficit or surpluskg per week × 7,700 ÷ 7, or lb per week × 3,500 ÷ 7
- Macrosprotein & carbs 4 kcal/g · fat 9 kcal/g
A rate given as % of body weight is turned into kg first. The tool warns when the target is below your BMR, below 1,200 kcal (women) or 1,500 kcal (men), or when the rate is over 1% of body weight a week, and it won't plan more than 2.5% a week.
Worked example
The calculator's starting values in metric: a 30-year-old man, 80 kg, 180 cm, moderately active, losing 0.5 kg a week.
- BMR = 800 + 1,125 − 150 + 5 = 1,780 kcal
- Maintenance = 1,780 × 1.55 = 2,759 kcal
- Deficit = 0.5 × 7,700 ÷ 7 = 550 kcal a day
- Target = 2,759 − 550 = 2,209 kcal
- Balanced 30/40/30: 663 + 883 + 663 kcal = 166 g protein, 221 g carbs, 74 g fat
- Three meals: 737 + 736 + 736 kcal, with 56 + 55 + 55 g protein
Daily calories by goal: examples
Calculated with the same formulas as the tool above. 0.5 kg is about 1.1 lb, 0.25 kg about 0.55 lb. Your own numbers depend on your age, size and activity.
| Person | Lose 0.5 kg / wk | Lose 0.25 kg / wk | Maintain | Gain 0.25 kg / wk |
|---|---|---|---|---|
| Woman, 3565 kg (143 lb), 165 cm (5 ft 5 in), light activity | 1,299* | 1,574 | 1,849 | 2,124 |
| Man, 3080 kg (176 lb), 180 cm (5 ft 11 in), moderate activity | 2,209 | 2,484 | 2,759 | 3,034 |
| Woman, 5575 kg (165 lb), 160 cm (5 ft 3 in), sedentary | 1,027* | 1,302* | 1,577 | 1,852 |
| Man, 4595 kg (209 lb), 175 cm (5 ft 9 in), light activity | 1,958 | 2,233 | 2,508 | 2,783 |
kcal per day. * Below the person's estimated BMR or below 1,200 kcal (women) / 1,500 kcal (men) — the calculator shows a warning for these.
Limitations and sources
Every number here is an estimate. Mifflin-St Jeor predicts resting energy from size, age and sex but not body composition, and activity multipliers are rough. The 7,700 kcal-per-kg (3,500 per lb) figure is a rule of thumb: real weight change slows as your body adapts, so track your weight for 2–3 weeks and adjust by 100–200 kcal. This tool isn't suitable for children, pregnancy or breastfeeding, or for planning a diet around a medical condition.
Sources, checked 7 October 2026: Harvard Health Publishing, "Calorie counting made easy" (minimum intake 1,200 kcal women / 1,500 kcal men); CDC, "Losing Weight" (1–2 lb a week); Hall & Chow, International Journal of Obesity 2013, "Why is the 3500 kcal per pound weight loss rule wrong?"; National Academies Dietary Reference Intakes (protein RDA 0.8 g/kg; AMDR 45–65% carbs, 20–35% fat, 10–35% protein); Jäger et al., ISSN position stand: protein and exercise, 2017 (1.4–2.0 g/kg); Mifflin et al., American Journal of Clinical Nutrition 1990.
Frequently asked questions
How many calories should I eat to lose weight?+
Start from your maintenance calories (TDEE) and subtract a deficit. About 500 kcal a day is roughly 1 lb (0.45 kg) a week using the 3,500 kcal-per-pound rule of thumb. For a 30-year-old man of 80 kg and 180 cm with moderate activity, maintenance is about 2,759 kcal, so losing 0.5 kg a week means about 2,209 kcal a day. The CDC notes that people who lose about 1–2 lb a week are more likely to keep it off.
Is 3,500 calories really one pound of fat?+
It's an approximation (about 7,700 kcal per kg), fine for setting a starting target. It isn't a prediction: NIH researchers Hall and Chow showed the rule overestimates long-term weight loss because your energy needs fall as you lose weight. Expect progress to slow, and re-run the calculator with your new weight every few weeks.
What is the lowest number of calories I should eat?+
Harvard Health advises that calorie intake should not fall below 1,200 a day for women or 1,500 a day for men, except under the supervision of a health professional. The calculator warns you when a target drops below these figures or below your estimated BMR.
How much protein do I need?+
The adult RDA is 0.8 g of protein per kg of body weight (about 0.36 g per lb) — enough to meet basic needs. The International Society of Sports Nutrition suggests 1.4–2.0 g/kg a day for most people who exercise. Use the custom macro option to set protein by body weight.
Which macro split should I choose?+
US guidelines (the Acceptable Macronutrient Distribution Ranges) give 45–65% of calories from carbs, 20–35% from fat and 10–35% from protein for adults. The balanced and high-protein presets sit inside those ranges; low carb and keto deliberately go below the carb range. The best split is one you can stick to.
Why is this different from the TDEE calculator?+
It uses the same Mifflin-St Jeor formula and activity multipliers, so maintenance calories match. This tool adds a goal you choose — a weekly rate in kg, lb or % of body weight — safety warnings, more macro options and a per-meal breakdown.
Is this medical advice?+
No. The numbers are estimates for planning. Talk to a doctor or registered dietitian before a large deficit, or if you are pregnant or breastfeeding, under 18, have a medical condition or a history of disordered eating. Nothing you enter is uploaded; it's saved on this device only if you tick "Remember my details".