Maintenance Calories Calculator

Maintenance calories are the number of calories you can eat each day and keep your weight exactly the same. Eat more and you gain; eat less and you lose. Every diet plan starts from this number — it is your personal "break-even" point, and understanding it is the difference between guessing your calories and knowing them.

Why the word "maintenance" matters

In a world full of "eat this many calories to lose weight" advice, the maintenance number is the quiet foundation underneath it all. It is not a fixed law of nature but something you can discover for yourself: estimate it from a formula, follow the estimate for a week or two while weighing yourself regularly, and then adjust until the scale stops moving. At that point you have found your true maintenance — usually within a couple of hundred calories of the estimate, but occasionally further off. That feedback loop is the most reliable tool you own, because it accounts for everything the formulas cannot: your personal muscle mass, hormones and genes.

Step 1 — your BMR

Your BMR is the energy you burn at complete rest. Two common formulas:

Mifflin-St Jeor:
  Men:   10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
  Women: 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

Katch-McArdle (needs body fat %):
  BMR = 370 + 21.6 × lean body mass(kg)

Step 2 — multiply by activity

For a 30-year-old man, 175 cm, 75 kg, moderate activity:

BMR = 750 + 1093.75 − 150 + 5 ≈ 1,699 kcal
Maintenance = 1,699 × 1.55 ≈ 2,633 kcal/day

Which BMR formula should you use?

The two options answer slightly different questions. Mifflin-St Jeor needs only height, weight, age and sex, so it is easy and robust — a great default. Katch-McArdle uses your lean body mass, which makes it more accurate for people who are unusually muscular or carry high body fat, but only if your body-fat figure is trustworthy. If you are unsure of your body fat percentage, Mifflin-St Jeor is usually the safer choice; if you have a reliable reading, Katch-McArdle can tighten the estimate.

Step 3 — targets

• Cut (fat loss): ~85% of maintenance ≈ 2,238 kcal. A deficit of 500 kcal/day ≈ 0.5 kg/week.
• Bulk (muscle gain): ~115% of maintenance ≈ 3,028 kcal.

A common trap

It is tempting to use a maintenance estimate as an exact daily quota, but remember that the number moves as you do. Lose weight and your maintenance falls; gain muscle and it rises. Recalculate when your weight has shifted by a few kilograms or your activity level changes, and treat any formula result as a starting point rather than an unbreakable target. This content is for general education and is not medical advice — seek professional guidance for individualised care.