Calorie Calculator

How to Use the Calorie Calculator

This calculator estimates Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) using Mifflin-St Jeor, Revised Harris-Benedict, or Katch-McArdle formulas. It then calculates calorie targets for weight loss and weight gain at different rates. Supports metric and imperial units. These are population estimates. Consult a healthcare provider before making significant dietary changes.

Calculation Modes

Metric

Enter your stats in metric units. Select a BMR formula from the dropdown. When you choose Katch-McArdle, a Body Fat % field appears and age becomes optional. The calculator shows BMR as the primary result and TDEE in a secondary read-only field.

Example: 30-year-old male, 180 cm, 80 kg, Moderate activity, Mifflin-St Jeor

• Age: 30
• Gender: Male
• Height: 180
• Weight: 80
• Activity Level: Moderate
• Formula: Mifflin-St Jeor
• BMR: 1,780
• TDEE: 2,759

After calculating, three tables appear:

• Calorie Breakdown: BMR, TDEE (with the calculation shown), formula used, activity level
• Weight Loss Targets: Mild Loss (~0.5 lb/week), Weight Loss (~1 lb/week), Extreme Loss (~2 lb/week)
• Weight Gain Targets: Mild Gain (~0.5 lb/week), Weight Gain (~1 lb/week), Fast Gain (~2 lb/week)

Example: 28-year-old male, 175 cm, 75 kg, Active, Katch-McArdle with 15% body fat

• Age: 28
• Gender: Male
• Height: 175
• Weight: 75
• Activity Level: Active
• Formula: Katch-McArdle
• Body Fat %: 15
• BMR: 1,747
• TDEE: 3,013.575

After calculating, the same three tables appear. The Calorie Breakdown shows Katch-McArdle as the formula used and the TDEE calculation. Age and gender do not affect the result because this formula uses lean body mass.

Imperial

Enter your stats in imperial units. Height uses feet and inches separately. Weight is in pounds. The calculator converts internally to metric for the formulas. Select a BMR formula from the dropdown. When you choose Katch-McArdle, a Body Fat % field appears and age becomes optional.

Example: 35-year-old female, 5 feet 4 inches, 140 lbs, Sedentary, Mifflin-St Jeor

• Age: 35
• Gender: Female
• Height (ft): 5
• Height (in): 4
• Weight: 140
• Activity Level: Sedentary
• Formula: Mifflin-St Jeor
• BMR: 1,315.0288
• TDEE: 1,578.0346

After calculating, three tables appear:

• Calorie Breakdown: BMR, TDEE (with the calculation shown), formula used, activity level
• Weight Loss Targets: Mild Loss (~0.5 lb/week), Weight Loss (~1 lb/week), Extreme Loss (~2 lb/week)
• Weight Gain Targets: Mild Gain (~0.5 lb/week), Weight Gain (~1 lb/week), Fast Gain (~2 lb/week)

Example: 40-year-old male, 6 feet 0 inches, 185 lbs, Very Active, Revised Harris-Benedict

• Age: 40
• Gender: Male
• Height (ft): 6
• Height (in): 0
• Weight: 185
• Activity Level: Very Active
• Formula: Revised Harris-Benedict
• BMR: 1,863.1259
• TDEE: 3,539.9393

After calculating, the same three tables appear. The Calorie Breakdown shows Revised Harris-Benedict as the formula used and the TDEE calculation.

Precision and Notation Settings

Use the settings bar above the tabs to control how results display:

• Decimal places: Adjust from 0 to 16 decimal places (default is 8)
• Notation: Switch between auto, fixed, exponential, and engineering notation (default is auto)

Your decimal places and notation settings save to your browser automatically. When you return to this calculator, your last chosen format loads without needing to adjust it again.

Common Use Cases

Finding Maintenance Calories

You are 30, male, 180 cm, 80 kg, exercise 4-5 times/week:

1. Switch to Metric
2. Enter 30 as Age, male as Gender
3. Enter 180 as Height, 80 as Weight
4. Select Moderate activity, Mifflin-St Jeor formula
5. TDEE: 2,759 (eat this amount daily to maintain weight)

Planning Weight Loss

You are 25, female, 160 cm, 55 kg, light activity:

1. Switch to Metric
2. Enter 25 as Age, female as Gender
3. Enter 160 as Height, 55 as Weight
4. Select Light activity, Mifflin-St Jeor
5. TDEE: 1,738
6. Weight Loss target: 1,238 calories/day (500 below TDEE)

Building Muscle

You are 30, male, 180 cm, 80 kg, moderate activity:

1. Switch to Metric
2. Enter 30 as Age, male as Gender
3. Enter 180 as Height, 80 as Weight
4. Select Moderate activity, Mifflin-St Jeor
5. TDEE: 2,759
6. Weight Gain target: 3,259 calories/day (500 above TDEE)

Comparing BMR Formulas

You want to see how Mifflin-St Jeor and Harris-Benedict differ for your stats:

1. Calculate with Mifflin-St Jeor, note BMR
2. Switch formula to Revised Harris-Benedict
3. Recalculate and compare the two values

Using Imperial Measurements

You are 35, female, 5'4", 140 lbs, sedentary:

1. Switch to Imperial
2. Enter 35 as Age, female as Gender
3. Height (ft): 5, Height (in): 4, Weight: 140
4. Select Sedentary, Mifflin-St Jeor
5. BMR: 1,315.0288, TDEE: 1,578.0346

Using Body Fat % for Accuracy

You had a DEXA scan showing 15% body fat and want the most accurate estimate:

1. Select Katch-McArdle formula
2. The Body Fat % field appears
3. Enter your body fat percentage
4. Calculate (this formula uses lean mass instead of age and gender assumptions)

Tips for Accurate Calculations

1. Mifflin-St Jeor is the default for a reason: it is the most accurate for the general population
2. Katch-McArdle needs accurate body fat %: a guessed body fat percentage makes Mifflin-St Jeor more reliable
3. Be honest about activity level: most people overestimate; a desk job with 3 workouts per week is usually Light, not Moderate
4. Weight loss targets have safety floors: the calculator will not go below 1,500 calories/day for men or 1,200 for women
5. TDEE is BMR multiplied by activity: the breakdown table shows this calculation explicitly
6. Katch-McArdle ignores age and gender: when selected, age becomes optional because the formula uses lean mass
7. All values are daily amounts: multiply by 7 for weekly planning

Troubleshooting

Required

This appears when a field is left empty. Enter a value in all required fields before calculating.

Age must be 15-80

The Mifflin-St Jeor and Harris-Benedict formulas are validated for adults aged 15 to 80. For Katch-McArdle, age is optional.

Please select a gender

Gender is required for Mifflin-St Jeor and Harris-Benedict. Select male or female from the dropdown.

Height must be positive

Enter a positive height. Zero and negative heights are rejected.

Weight must be positive

Enter a positive weight. Zero and negative weights are rejected.

Please select an activity level

Choose one of the six activity levels from the dropdown.

Please select a formula

Choose Mifflin-St Jeor, Revised Harris-Benedict, or Katch-McArdle from the dropdown.

Body fat % required (0-100) for Katch-McArdle

When using Katch-McArdle, enter a body fat percentage greater than 0 and less than 100.

Height (inches) must be 0-11.9

In imperial mode, inches must be less than 12. Convert excess inches to feet (for example, 5 feet 13 inches should be 6 feet 1 inch).

Height (feet) cannot be negative

In imperial mode, the feet portion of height cannot be negative.

Details tables not appearing

The details section renders after a successful calculation with no validation errors. Check that all required fields are filled and valid, then click Calculate.