How to use this calculator
- Enter or choose sex.
- Enter or choose age.
- Enter or choose units.
- Enter or choose activity level.
- Enter or choose goal.
- The calories per day for your goal updates as you type. Use Copy result or Share to keep it.
Method
BMR = 10W + 6.25H − 5A + s; Maintenance = BMR × activity factor; Target = Maintenance + (weekly change in kg × 7,700 ÷ 7)
- W
- weight in kg
- H
- height in cm
- A
- age in years
- s
- +5 for men, −161 for women
- activity factor
- 1.2 (sedentary) to 1.9 (extremely active)
- 7,700
- approximate kcal in 1 kg of body-weight change
Worked example
- BMR = 10 × 60 + 6.25 × 165 − 5 × 30 − 161 = 600 + 1,031.25 − 150 − 161 = 1,320.25 kcal.
- Maintenance = 1,320.25 × 1.55 (moderately active) = 2,046 kcal a day.
- Losing 0.5 kg a week needs about 0.5 × 7,700 ÷ 7 = 550 kcal a day less.
- Target = 2,046 − 550 ≈ 1,496 kcal a day.
A moderately active 30-year-old woman, 165 cm and 60 kg, needs about 2,046 kcal a day to maintain her weight, or about 1,496 kcal to lose roughly 0.5 kg a week.
What the result means
Treat the number as a starting point. Track your weight for two to four weeks; if it moves faster or slower than planned, adjust intake by 100–200 kcal a day. Weight loss usually slows over time as the body adapts, so the same deficit produces less loss later on.
Assumptions and limits
- Mifflin–St Jeor equation for resting energy expenditure in healthy adults.
- Conventional activity multipliers: 1.2, 1.375, 1.55, 1.725 and 1.9.
- About 7,700 kcal per kg of body-weight change (the metric form of the “3,500 kcal per pound” rule).
- Individual energy needs can differ noticeably from any prediction equation.
- The 7,700 kcal rule ignores metabolic adaptation, so it overstates long-term weight loss (Hall, 2008).
- Not for children, pregnancy or breastfeeding, or people with medical conditions that affect metabolism.
Questions
What is the difference between this and the BMR calculator?
The BMR calculator gives resting energy and a table by activity level. This page adds a weight goal and shows the daily calories needed to reach it.
Is it safe to lose 1 kg a week?
For many people it means a deficit of about 1,100 kcal a day, which is hard to sustain and can leave intake below resting needs. A slower rate is easier to keep up; talk to a doctor or dietitian before a large deficit.
Why has my weight loss slowed on the same calories?
As you lose weight your energy needs fall, and the body adapts. Recalculate with your new weight every few kilograms.
Sources
Please note: This is a general screening estimate for adults, not medical advice or a diagnosis. Talk to a qualified health professional about your health.