Calorie Needs Calculator
Mifflin-St Jeor for resting rate, multiplied by an activity factor. Shows maintenance, a mild deficit and a mild surplus.
Resting rate (BMR)
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Maintenance
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Mild deficit (−15%)
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Mild surplus (+10%)
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Worked example
A 30-year-old male at 175 cm and 75 kg has a resting rate near 1,700 kcal. At moderate activity the maintenance figure lands around 2,640.
Mifflin-St Jeor predicts resting energy expenditure from four inputs and is accurate within about 10% for most people. The activity multiplier is the weak link: self-reported activity levels are consistently overestimated, which is why the maintenance figure often comes out higher than reality.