Calories Calculator
Estimate daily calorie intake (TDEE & BMR) for weight loss or muscle gain.
This calorie calculator - useful as a calorie counter, calories intake calculator, weight loss calculator, or maintenance calorie calculator - estimates your daily calorie needs using the Mifflin-St Jeor equation, one of the most widely validated formulas for predicting Basal Metabolic Rate (BMR) - the calories your body burns at complete rest. Multiplying BMR by an activity multiplier produces your Total Daily Energy Expenditure (TDEE), the calorie level needed to maintain your current weight.
Enter your age, sex, height, weight, and activity level to see your maintenance calories, along with adjusted targets for weight loss or weight gain.
Worked Calculation Examples
| Scenario | Result | Calculation Step |
|---|---|---|
| 30yo Male, 80kg, 180cm, Moderately Active | 2,735 kcal/day | Maintenance calories are 2,735 kcal. For weight loss, aim for ~2,235 kcal. |
Popular Scenarios & Specific Calculations
BMR vs. TDEE: What's the Difference
BMR is the energy your body would burn in 24 hours if you did nothing but rest - it powers basic functions like breathing, circulation, and cell repair. TDEE takes BMR and multiplies it by an activity factor (ranging from roughly 1.2 for a sedentary lifestyle to 1.9 for very intense daily training) to estimate total calories burned including movement and exercise. TDEE, not BMR, is the number that represents your actual maintenance calorie level.
How a Calorie Deficit or Surplus Works
One pound of body fat represents roughly 3,500 stored calories. A daily deficit of 500 calories below your TDEE - through eating less, moving more, or both - therefore produces an average rate of about one pound of weight loss per week. Larger deficits speed up short-term loss but increase the risk of muscle loss and metabolic slowdown; most guidelines recommend a deficit of 500-750 calories per day as a sustainable range for most adults. The same logic applies in reverse for weight gain: a surplus of roughly 250-500 calories per day supports gradual, mostly lean weight gain when combined with resistance training.
Why Calorie Needs Vary Between People
Two people of the same age, height, and weight can still have meaningfully different calorie needs due to differences in muscle mass (which burns more calories at rest than fat tissue), genetics, and non-exercise daily movement. This calculator gives a solid starting estimate, but the only way to know your true maintenance level is to track your actual weight change over 2-3 weeks at a given calorie intake and adjust from there.
How to Use the Calories Calculator
- Open the Calories Calculator and enter the values requested in the input fields.
- Check the units, percentages, dates, or time periods before reading the answer.
- Review the instant result and adjust any value to compare another scenario.
- Use the formula, example, and FAQs below to understand how the calorie calculator works.
Frequently Asked Questions
How many calories should I eat to lose weight?
Since one pound of fat represents roughly 3,500 calories, a daily deficit of about 500 calories below your maintenance (TDEE) level produces an average weight loss of approximately one pound per week - this calculator shows how many calories that means for your specific stats.
What is the difference between BMR and TDEE?
BMR is the calories your body burns at complete rest. TDEE multiplies BMR by an activity factor to estimate total calories burned in a day, including movement and exercise - TDEE is the number to use for weight maintenance planning.
Is a bigger calorie deficit always better for weight loss?
No. Deficits larger than about 750-1000 calories per day increase the risk of muscle loss, nutrient deficiency, and metabolic slowdown. A moderate, sustainable deficit is generally more effective long-term than an aggressive one.
Why does this calculator ask for my activity level?
Activity level is used as a multiplier on your BMR to estimate total daily calories burned - someone who exercises intensely most days burns significantly more than someone who is mostly sedentary, even at the same BMR.
How accurate is the Mifflin-St Jeor equation?
It's considered one of the more accurate predictive equations for BMR in research comparisons, though individual variation of 10-15% is normal - actual weight change over a few weeks is the most reliable way to confirm your personal calorie needs.
Should I eat the same calories every day?
Not necessarily - many people find a consistent weekly average easier to sustain than an identical daily target, as long as the overall weekly intake matches their goal (deficit, maintenance, or surplus).
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Last updated: September 29, 2026.