Calorie estimates should explain themselves.
This calculator uses the Mifflin-St Jeor equation to estimate your resting calorie burn, then shows how your activity estimate changes the final daily total.
The important part: “sedentary” is not always the same for everyone. A custom steps mode can help show when the standard multiplier may be too generous.
Calculator
The standard sedentary setting adds roughly 20% above your resting estimate.
Leave blank to estimate from height.
1.10 is deliberately conservative.
Step calories are estimated from distance, body weight, and a simple walking cost. This is useful for comparison, not precision.
What is the Mifflin-St Jeor equation?
It is an equation used to estimate how many calories your body burns at rest. That means breathing, keeping warm, powering your organs, and generally staying alive before deliberate exercise is added.
The equation
Many calculators call this BMR. More accurately, the equation estimates resting energy expenditure, but BMR is the common label most people recognise.
Weight
Higher body weight usually means more tissue to maintain, so the estimate increases.
Height
Height helps approximate body size, which also affects resting energy needs.
Age
The equation subtracts more as age increases, reflecting lower average resting energy use.
Why activity level matters so much
Once your resting estimate has been calculated, many calculators multiply it by an activity factor. This gives an estimated TDEE: Total Daily Energy Expenditure.
The problem is that people often pick “sedentary” and assume it is precise. It is not. Standard sedentary is usually BMR × 1.20, which adds roughly 20% above the resting estimate. That may be fine for a desk-job day with normal pottering around, but it may be too generous for very low movement days.
Common activity multipliers
Why custom steps mode exists
Step counters give us a useful reality check. They are not perfect, but they can stop us overestimating how active we are.
A commonly used step-count guide describes under 5,000 steps per day as a sedentary lifestyle index. So if someone is averaging much lower than that, the standard sedentary multiplier may overestimate their real daily burn.
The custom steps idea
This page uses BMR × 1.10 as the default conservative base in custom mode, then adds an estimate for walking calories from your step count. This is not laboratory precision, but it can be more honest than blindly adding 20% for everyone.
How to use the result
Treat the number as a starting estimate. Run it for two to four weeks, watch your body-weight trend, waist measurement, hunger, energy, and consistency, then adjust.
If weight is not moving as expected, the equation has not failed. It simply means the estimate needs calibrating against real-world data.
This tool is for education and personal estimation. It is not medical advice. Anyone with a medical condition, history of disordered eating, pregnancy, or complex health needs should seek professional guidance.
Sources
- Mifflin MD, St Jeor ST, Hill LA, et al. A new predictive equation for resting energy expenditure in healthy individuals. PubMed
- Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults. PubMed
- Tudor-Locke C, Bassett DR. How many steps/day are enough? PubMed
- Tudor-Locke C, Craig CL, Thyfault JP, Spence JC. A step-defined sedentary lifestyle index. PubMed