Your maintenance calories are the daily energy intake your body needs to hold your current weight steady. They combine your resting metabolic rate with the energy burned through daily movement and exercise. Knowing that number gives you a reliable starting point for weight loss, muscle gain, or simply eating in balance day to day.
This calorie maintenance calculator estimates your total daily energy expenditure using the widely validated Mifflin-St Jeor equation, then applies an activity multiplier based on your typical weekly routine. If you know your body-fat percentage, switch on the Katch-McArdle option for a more personalised lean-mass-based estimate.
It is a practical planning tool for anyone tracking calories, training consistently, or managing body composition. Use the results as a baseline, then refine the number based on real-world changes in your weight over a couple of weeks.
⚖️ Calorie Maintenance Calculator
Estimate your daily maintenance calories with the Mifflin-St Jeor or Katch-McArdle equation.
Step-by-Step Guide
Start by selecting your sex and entering your age, height, and weight. Height and weight can be entered in either metric or imperial units — the calculator converts automatically. Next, choose the activity level that best matches your typical week. If you are unsure, choose the more conservative option: most people overestimate how active they are. The quick-set buttons below the activity menu let you switch between the five standard levels without opening the dropdown.
If you know your body-fat percentage from a DEXA scan, skinfold measurement, or bioelectrical impedance scale, tick the body-fat checkbox. The calculator will then switch to the Katch-McArdle equation, which uses lean body mass directly and is generally more accurate for athletic individuals. Press Calculate maintenance to see your result, a step-by-step breakdown, and a practical ±5% target range. Use the Reset button to clear everything and start a new estimate.
Formula Explained
Your maintenance calories equal your basal metabolic rate (BMR) multiplied by an activity factor. BMR is the energy your body uses at complete rest just to keep you alive — breathing, circulating blood, and maintaining body temperature. This calculator uses two well-known BMR equations. The default is the Mifflin-St Jeor equation, developed in 1990 and widely recommended by dietitians and medical bodies:
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
When body-fat percentage is provided, the calculator uses the Katch-McArdle formula instead:
BMR = 370 + 21.6 × lean body mass (kg)
Lean body mass = total weight(kg) × (100 − body fat %) ÷ 100
Both equations give energy in calories per day. The final step multiplies BMR by an activity multiplier based on the five standard levels:
| Activity level | Description | Multiplier |
|---|---|---|
| Sedentary | Little or no exercise, desk job | 1.20 |
| Light | Exercise 1–3 days per week | 1.375 |
| Moderate | Exercise 3–5 days per week | 1.55 |
| Very active | Exercise 6–7 days per week | 1.725 |
| Extra active | Hard exercise plus physical job or twice-daily training | 1.90 |
Worked Examples
Example 1 — Mifflin-St Jeor: A 30-year-old woman, 165 cm tall and 70 kg, exercising 3–5 days per week. Her BMR = 10×70 + 6.25×165 − 5×30 − 161 = 1420 calories/day. Maintenance = 1420 × 1.55 ≈ 2200 calories/day. Her ±5% range is roughly 2090–2310 calories/day.
Example 2 — Katch-McArdle: A 25-year-old man, 85 kg with 15% body fat, very active. Lean mass = 85 × (100 − 15) ÷ 100 = 72.25 kg. BMR = 370 + 21.6 × 72.25 ≈ 1931 calories/day. Maintenance = 1931 × 1.725 ≈ 3331 calories/day. The Mifflin-St Jeor estimate for the same man would be around 3110 calories/day — the difference illustrates why body composition matters.
Common Mistakes to Avoid
- Choosing an activity level that is too high. Most people classify themselves as “moderate” when a desk job plus a few workouts is closer to “light”.
- Treating the result as a fixed daily target. Maintenance is an estimate; watch your average weight over 1–2 weeks and adjust by about 100–200 calories in the right direction if needed.
- Skipping the body-fat option when you have a reliable measurement. The Katch-McArdle equation can be noticeably more accurate for athletes and people with high muscle mass.
- Ignoring the ±5% range. Small daily fluctuations in food, exercise, and measuring make a 100–200 calorie range more realistic than a single number.
Factors Affecting Accuracy
No calorie formula is perfectly precise. Individual variation in metabolism can be 10% or more, which means your true maintenance could be 150–250 calories away from the estimate. Accuracy depends on how carefully you measure height and weight, whether your body-fat percentage is real rather than guessed, and how honest your activity selection is.
Your energy needs also change. If you lose a significant amount of weight, your BMR drops because there is less tissue to maintain. If you start a new training programme, your maintenance can rise. Recalculate every time your weight shifts by about 5 kg (11 lb) or whenever your activity routine changes substantially. Non-exercise activity such as walking, fidgeting, and household work can make a bigger difference than many people realise, and it is difficult to capture in any equation.
Frequently Asked Questions
Is the calorie maintenance number the same as my TDEE? Yes. Maintenance calories and total daily energy expenditure (TDEE) refer to the same figure: total calories burned in a typical day. The term “maintenance” simply describes what happens if you eat exactly that amount.
How much should I cut or add for weight change? A moderate deficit of 300–500 calories per day supports fat loss of about 0.3–0.5 kg per week. A surplus of 200–300 calories per day supports gradual muscle gain. Avoid extreme cuts, which can slow metabolism and reduce training performance.
Should I trust my fitness tracker instead? Tracker estimates vary widely and are often based on the same equations with added assumptions about heart rate. Use this calculator as your baseline, then compare tracker numbers over time. The National Institute of Diabetes and Digestive and Kidney Diseases offers a data-driven Body Weight Planner that predicts weight changes from calorie intake — a useful companion tool.
Additional Resources
- NIDDK Body Weight Planner — models individual weight change over time.
- Mifflin-St Jeor equation on Wikipedia — background and comparison with older formulas.
- Original Mifflin et al. study (PubMed, 1990) — the research behind the equation used in this calculator.