What is the BMR for a 40-year-old woman?

The estimated BMR (basal metabolic rate) for a 40-year-old woman of average height and weight is 1391 kcal/day, calculated using the Mifflin-St Jeor equation.

Calorie Guide · Age 40

Calories for a 40-Year-Old Woman

Q: How many calories does a 40-year-old woman need?

A lightly active 40-year-old woman of average weight and height needs approximately 1913 kcal/day to maintain weight. Sedentary needs are around 1669 kcal, and very active around 2400 kcal.

Q: How many calories should a 40-year-old woman eat to lose weight?

A 40-year-old woman should eat approximately 1413 kcal/day to lose about 0.5 kg (1 lb) per week. This is a 500 kcal deficit from the estimated maintenance of 1913 kcal.

BMR, TDEE and exact calorie targets for weight loss, maintenance and muscle gain at age 40.

Calorie Needs at Age 40 — Average Woman

1391

BMR (at rest)

1669

Sedentary TDEE

1913
Lightly active TDEE

2156

Moderately active

1413

Weight loss target

1913

Maintenance

2213

Muscle gain target

How Many Calories Does a 40-Year-Old Woman Need?

Using the Mifflin-St Jeor equation with average US height and weight for a woman aged 40, the resting metabolic rate (BMR) is approximately 1391 kcal/day. With typical daily activity included, total calorie expenditure (TDEE) ranges from 1669 kcal (sedentary) to 2400 kcal (very active).

Age 40 note: Metabolism begins slowing ~1–2% per decade after 30. Maintaining muscle through resistance training and adequate protein (0.7–1 g/lb) offsets most of this decline.

Calorie Targets by Goal

Goal	Daily Calories	Expected Result
🔵 Aggressive weight loss	1163 kcal	~0.75 kg/week
📉 Weight loss	1413 kcal	~0.5 kg/week
✅ Maintenance	1913 kcal	Weight stable
💪 Lean bulk	2213 kcal	~0.25 kg/week
🏋️ Aggressive bulk	2413 kcal	~0.5 kg/week

Calorie Needs by Activity Level

Activity Level	Description	Daily Calories
Sedentary	Desk job, minimal movement	1669 kcal
Lightly active	1–3 workouts/week	1913 kcal
Moderately active	3–5 workouts/week	2156 kcal
Very active	Hard training 6–7 days/week	2400 kcal

How Metabolism Changes Around Age 40

Metabolic rate declines approximately 1–2% per decade after age 30, driven primarily by muscle loss (sarcopenia) rather than any inherent slowdown. At age 40, your BMR of 1391 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 40
30	1441 kcal	+50 kcal
35	1416 kcal	+25 kcal
40	1391 kcal	—
45	1366 kcal	-25 kcal
50	1341 kcal	-50 kcal

Macronutrient Split at 1913 kcal

Macro	% of Calories	Grams/day	Calories
Protein	30%	143 g	572 kcal
Carbohydrates	40%	191 g	764 kcal
Fat	30%	64 g	576 kcal

At age 40, 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 40-year-old woman need per day?A lightly active 40-year-old woman of average size needs approximately 1913 kcal/day to maintain weight. This ranges from 1669 kcal (sedentary) to 2400 kcal (very active).

How many calories should a 40-year-old woman eat to lose weight?Aim for 1413 kcal/day — a 500 kcal deficit from the 1913 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 40 affect how many calories you burn?Yes. Every decade after 30, BMR drops ~1–2% mainly due to muscle loss. At age 40 the estimated BMR is 1391 kcal — compare to 1441 kcal at age 30. Resistance training largely offsets this decline.

Related Age Guides

Sources

WHO CDC Mifflin-St Jeor (PubMed)