Calorie Needs — Find Your Daily Calorie Target for Weight and Energy
The Calorie Needs calculator estimates how many calories you need each day to maintain your current weight based on your size, age, sex, and activity level. It uses the Mifflin–St Jeor equation for basal metabolic rate (BMR) and multiplies by an activity factor to get your total daily energy expenditure (TDEE). Whether you want to maintain, lose, or gain weight, having a clear number helps you plan meals and set realistic goals.
What Does This Tool Do?
This tool computes your estimated total daily energy expenditure (TDEE)—the number of calories your body typically burns in a day. It first calculates your basal metabolic rate (BMR), the calories you use at rest, using the widely accepted Mifflin–St Jeor formula. Then it multiplies BMR by an activity factor (sedentary, light, moderate, active, or very active) to account for movement and exercise. The result is a maintenance calorie level. Eating around this number supports weight maintenance; eating less can support gradual weight loss, and eating more can support gain. The estimate is not personalised to your exact metabolism or body composition, so treat it as a starting point and adjust based on results and, if needed, a dietitian's advice.
How to Use It (Step-by-step)
TDEE = BMR × activity factor (1.2 sedentary → 1.9 very active)BMR: Mifflin–St Jeor equation (weight, height, age, sex)- 1Step 1:
Enter your weight in kg.
- 2Step 2:
Enter your height in cm.
- 3Step 3:
Enter your age in years.
- 4Step 4:
Select your sex (male or female)—the BMR formula differs by sex.
- 5Step 5:
Choose your activity level: Sedentary (little or no exercise), Light (1–3 days per week), Moderate (3–5 days), Active (6–7 days), or Very active (intense daily). Pick the option that best matches your typical week, not just exercise days.
- 6Step 6:
Click Calculate.
- 7Step 7:
Read your estimated daily calories to maintain weight. To lose weight, many people eat 250–500 kcal less; to gain, 250–500 kcal more—adjust gradually and consider professional guidance for larger changes.
Key Features
The calculator uses the Mifflin–St Jeor equation for BMR, which is well validated for adults. It applies standard activity multipliers (1.2 to 1.9). Results are in kilocalories (kcal) per day, rounded to a whole number. The tool is free, does not store data, and works on any device. It is intended for adults; older adults and athletes may need individualised adjustments. It does not account for body composition, hormones, or medical conditions—use it as a general guide. You can recalculate whenever your weight, activity, or age changes. Many dietitians use similar formulas as a first step before fine-tuning with food diaries or metabolic testing.
Use Cases
You might use the calorie needs calculator when: you want to know how much to eat to maintain weight; you are planning a moderate calorie deficit for weight loss and want a baseline; you are trying to gain weight or muscle and want a target above maintenance; you are building a meal plan and need a daily number to work from; or you are comparing your current intake to an estimated need. It is less accurate for people with very high or very low muscle mass, significant metabolic or hormonal issues, or those on very restrictive diets—in such cases, a dietitian can provide a more tailored estimate. People who have hit a weight plateau can use it to check if their intake matches their estimated expenditure. Coaches and trainers often use TDEE as a starting point before setting deficit or surplus targets for clients.
FAQ
Activity has a big impact. BMR is the same for a given weight, height, age, and sex, but the activity multiplier can add hundreds of calories. Be honest about your typical weekly activity.
A deficit of about 250–500 kcal per day often leads to a slow, sustainable loss (roughly 0.25–0.5 kg per week). Larger deficits can be harder to sustain and may need medical or dietitian support.
It is one of the most accurate simple formulas for BMR in adults. It still does not capture individual variation in metabolism, so use the result as an estimate and adjust based on your own results.
The activity level you choose already includes your usual exercise. If you do an extra hard or long workout occasionally, you might eat a bit more that day; you do not need to add every workout on top of a 'very active' selection.
The formula does not adjust for age beyond the basic equation or for conditions that affect metabolism. For personalised advice, see a dietitian or doctor.