Resting Metabolic Rate Calculator
RMR from Mifflin-St Jeor, Harris-Benedict and Katch-McArdle side by side.
Enter your values
Choose one of: Male, Female.
Enter the weight in kg.
Enter the height in cm.
Enter the age in years.
Enter the body fat (optional) in %.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Resting metabolic rate
- 1,740 kcal/day
- Mifflin-St Jeor
- 1,728 kcal
- Harris-Benedict
- 1,795 kcal
- Katch-McArdle
- 1,752 kcal
- Sedentary total
- 2,087 kcal/day
- Lightly active
- 2,392 kcal/day
- Moderately active
- 2,696 kcal/day
- Very active
- 3,001 kcal/day
Working
- 110 x 78 + 6.25 x 178 - 5 x 34 + 5 = 1,728 kcal
Quick answer
Resting metabolic rate is the energy your body uses at complete rest. Mifflin-St Jeor is the most accurate general equation; Katch-McArdle is better when body fat is known.
Mifflin: 10 x kg + 6.25 x cm - 5 x age + s
At a glance
| What it does | RMR from Mifflin-St Jeor, Harris-Benedict and Katch-McArdle side by side. |
|---|---|
| Category | Health |
| Inputs needed | Sex, Weight, Height, Age, Body fat (optional) |
| Main output | Resting metabolic rate |
| Formula | Mifflin: 10 x kg + 6.25 x cm - 5 x age + s |
| Cost | Free — no sign-up, no download |
How to use the Resting Metabolic Rate Calculator
- 1Enter your current weight, height and age.
- 2Add body fat percentage if you know it to unlock the Katch-McArdle estimate.
- 3Pick the activity multiplier that matches a typical week, not your best week.
Inputs explained
- Sex
- Choose one of: Male, Female.
- Weight(kg)
- Enter the weight in kg.
- Height(cm)
- Enter the height in cm.
- Age(years)
- Enter the age in years.
- Body fat (optional)(%)
- Enter the body fat (optional) in %.
Worked example
Using the values the calculator loads with:
Inputs
- SexMale
- Weight78 kg
- Height178 cm
- Age34 years
- Body fat (optional)18 %
Results
- Resting metabolic rate1,740 kcal/day
- Mifflin-St Jeor1,728 kcal
- Harris-Benedict1,795 kcal
- Katch-McArdle1,752 kcal
- Sedentary total2,087 kcal/day
- Lightly active2,392 kcal/day
- Moderately active2,696 kcal/day
- Very active3,001 kcal/day
- 10 x 78 + 6.25 x 178 - 5 x 34 + 5 = 1,728 kcal
Frequently asked questions
What is the difference between RMR and BMR?
BMR is measured after an overnight fast in a lab; RMR is a slightly higher real-world figure. The equations here are used interchangeably for both in practice.
Which equation should I trust?
Mifflin-St Jeor for most people, Katch-McArdle if you have a reliable body fat measurement and carry more muscle than average.
What do I need to enter into the Resting Metabolic Rate Calculator?
Just 5 values: sex, weight, height, age, body fat (optional). Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Resting Metabolic Rate Calculator work out the answer?
Resting metabolic rate is the energy your body uses at complete rest. Mifflin-St Jeor is the most accurate general equation; Katch-McArdle is better when body fat is known. It applies the formula Mifflin: 10 x kg + 6.25 x cm - 5 x age + s and shows the working so you can check each step by hand.
Is the Resting Metabolic Rate Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.