Calculator Inputs
Formula Used
This calculator estimates basal metabolic rate, then multiplies it by an activity factor. Extra weekly exercise calories are divided by seven and added as a daily value. A metabolic adjustment can increase or decrease the final maintenance estimate.
Mifflin St Jeor uses weight, height, age, and sex. Revised Harris Benedict uses a different clinical equation. Katch McArdle uses lean body mass when body fat percentage is known.
Daily sustain calories = ((BMR × activity factor) + daily exercise calories) × adjustment factor. Weekly calories = daily sustain calories × 7.
How to Use This Calculator
- Select your unit system.
- Enter age, sex, height, and weight.
- Add body fat percentage if you want lean mass calculation.
- Choose a BMR formula and activity level.
- Add extra weekly exercise calories if your activity factor excludes workouts.
- Set protein, fat, buffer range, and meal count.
- Press the calculate button.
- Download the result as CSV or PDF if needed.
Example Data Table
| Profile | Age | Weight | Height | Activity | Estimated Sustain Calories |
|---|---|---|---|---|---|
| Office worker | 32 | 72 kg | 176 cm | Lightly active | About 2,250 kcal |
| Regular gym user | 29 | 80 kg | 181 cm | Moderately active | About 2,850 kcal |
| Endurance athlete | 38 | 68 kg | 170 cm | Very active | About 2,950 kcal |
Understanding Weight Maintenance
Sustaining weight is not about eating the same food daily. It is about matching intake with total energy use over time. Your body spends calories on rest, movement, digestion, training, and normal temperature control. A maintenance target gives a practical starting point. It helps you plan meals without guessing.
Why Daily Needs Change
Calorie needs change with age, height, weight, sex, body composition, and activity. Muscle usually raises resting energy use. Long sitting lowers total daily burn. Hard training may raise it for one day, but recovery days can be lower. Stress, sleep, illness, and dieting history can also shift results. That is why this calculator offers several formulas.
Using Formula Results Wisely
No equation can know your exact metabolism. Mifflin St Jeor is often a solid default. Harris Benedict can compare another clinical estimate. Katch McArdle is useful when body fat percentage is known. The average method can smooth formula differences. Treat the final number as a measured estimate, not a rule.
Building a Stable Plan
Start with the calculated maintenance calories. Then track body weight for two to four weeks. Use morning weights and compare weekly averages. Daily weight changes often come from water, salt, food volume, and glycogen. Do not adjust calories after one high or low scale reading.
Macro Balance Matters
Protein supports muscle repair and fullness. Fat supports hormones and vitamin absorption. Carbohydrates support training, daily energy, and mood. The macro section converts calories into grams. You can adjust protein per kilogram and fat percentage. Remaining calories are assigned to carbohydrates.
Reviewing Progress
If weight rises for several weeks, reduce intake slightly. If weight falls, add a small amount. Changes of 100 to 200 calories can be enough. Large changes are rarely needed for maintenance. Keep activity consistent while testing your target.
Healthy Use Notes
This calculator is for general planning. It is not medical advice. People with pregnancy, eating disorders, diabetes, thyroid disease, kidney disease, or other medical concerns should seek professional guidance. A good maintenance plan should feel repeatable, flexible, and calm. It should support health, training, and normal life.
Small adjustments work best. Keep meals simple, monitor hunger, and review results with patience before changing the plan again slowly.
FAQs
What are sustain calories?
Sustain calories are the daily calories likely needed to keep your body weight stable. They are also called maintenance calories. The value can change with activity, body composition, sleep, stress, and normal daily movement.
Which formula should I choose?
Mifflin St Jeor is a strong general choice. Harris Benedict gives another comparison. Katch McArdle is useful when you know body fat percentage. The average option blends available formulas.
Why is body fat optional?
Only the Katch McArdle equation needs body fat percentage. Other formulas use weight, height, age, and sex. Leave body fat blank if you do not know it accurately.
How accurate is this calculator?
It gives an estimate, not a perfect measurement. Track your weekly weight average for two to four weeks. Adjust calories only after a clear trend appears.
What activity level should I select?
Choose the level that matches your normal week. Include job movement, walking, chores, and training. Avoid choosing a high level only because of one hard workout.
Should I include exercise calories?
Add exercise calories only if your selected activity factor does not already include them. Double counting exercise can make the maintenance estimate too high.
Why does the calculator show a range?
Maintenance is not a single exact number. A range allows normal changes in water, steps, food volume, and training. It helps you avoid overreacting to daily scale shifts.
Can this help with weight loss?
This page is built for weight maintenance. For weight loss, you would usually eat below maintenance. Use a safe, moderate change and seek professional advice when needed.