What is the BMR for a 18-year-old woman?

The estimated BMR (basal metabolic rate) for a 18-year-old woman of average height and weight is 1501 kcal/day, calculated using the Mifflin-St Jeor equation.

Calorie Guide · Age 18

Calories for a 18-Year-Old Woman

Q: How many calories does a 18-year-old woman need?

A lightly active 18-year-old woman of average weight and height needs approximately 2064 kcal/day to maintain weight. Sedentary needs are around 1801 kcal, and very active around 2589 kcal.

Q: How many calories should a 18-year-old woman eat to lose weight?

A 18-year-old woman should eat approximately 1564 kcal/day to lose about 0.5 kg (1 lb) per week. This is a 500 kcal deficit from the estimated maintenance of 2064 kcal.

BMR, TDEE and exact calorie targets for weight loss, maintenance and muscle gain at age 18.

Calorie Needs at Age 18 — Average Woman

1501

BMR (at rest)

1801

Sedentary TDEE

2064
Lightly active TDEE

2327

Moderately active

1564

Weight loss target

2064

Maintenance

2364

Muscle gain target

How Many Calories Does a 18-Year-Old Woman Need?

Using the Mifflin-St Jeor equation with average US height and weight for a woman aged 18, the resting metabolic rate (BMR) is approximately 1501 kcal/day. With typical daily activity included, total calorie expenditure (TDEE) ranges from 1801 kcal (sedentary) to 2589 kcal (very active).

Age 18 note: Metabolism is at its peak in your late teens and early twenties. Prioritize protein and resistance training to build muscle that pays dividends for decades.

Calorie Targets by Goal

Goal	Daily Calories	Expected Result
🔵 Aggressive weight loss	1314 kcal	~0.75 kg/week
📉 Weight loss	1564 kcal	~0.5 kg/week
✅ Maintenance	2064 kcal	Weight stable
💪 Lean bulk	2364 kcal	~0.25 kg/week
🏋️ Aggressive bulk	2564 kcal	~0.5 kg/week

Calorie Needs by Activity Level

Activity Level	Description	Daily Calories
Sedentary	Desk job, minimal movement	1801 kcal
Lightly active	1–3 workouts/week	2064 kcal
Moderately active	3–5 workouts/week	2327 kcal
Very active	Hard training 6–7 days/week	2589 kcal

How Metabolism Changes Around Age 18

Metabolic rate declines approximately 1–2% per decade after age 30, driven primarily by muscle loss (sarcopenia) rather than any inherent slowdown. At age 18, your BMR of 1501 kcal reflects your current muscle mass, height and hormonal status. The single most effective way to maintain or raise your BMR is resistance training — each kilogram of lean muscle burns roughly 13 kcal/day at rest.

Age	Estimated BMR (woman)	Change vs age 18
18	1501 kcal	—
18	1501 kcal	—
18	1501 kcal	—
23	1476 kcal	-25 kcal
28	1451 kcal	-50 kcal

Macronutrient Split at 2064 kcal

Macro	% of Calories	Grams/day	Calories
Protein	30%	155 g	620 kcal
Carbohydrates	40%	206 g	824 kcal
Fat	30%	69 g	621 kcal

At age 18, protein intake is especially important. Aim for at least 60–74 g/day to maintain muscle mass, whether you're in a deficit, at maintenance, or in a surplus.

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Frequently Asked Questions

How many calories does a 18-year-old woman need per day?A lightly active 18-year-old woman of average size needs approximately 2064 kcal/day to maintain weight. This ranges from 1801 kcal (sedentary) to 2589 kcal (very active).

How many calories should a 18-year-old woman eat to lose weight?Aim for 1564 kcal/day — a 500 kcal deficit from the 2064 kcal maintenance estimate — to lose approximately 0.5 kg per week. Never go below 1200 kcal (women) or 1500 kcal (men) for extended periods.

Does age 18 affect how many calories you burn?Yes. Every decade after 30, BMR drops ~1–2% mainly due to muscle loss. At age 18 the estimated BMR is 1501 kcal — compare to 1441 kcal at age 30. Resistance training largely offsets this decline.

Related Age Guides

Sources

WHO CDC Mifflin-St Jeor (PubMed)