What is the BMR for a 31-year-old woman?

The estimated BMR (basal metabolic rate) for a 31-year-old woman of average height and weight is 1436 kcal/day, calculated using the Mifflin-St Jeor equation.

Calorie Guide · Age 31

Calories for a 31-Year-Old Woman

Q: How many calories does a 31-year-old woman need?

A lightly active 31-year-old woman of average weight and height needs approximately 1975 kcal/day to maintain weight. Sedentary needs are around 1723 kcal, and very active around 2477 kcal.

Q: How many calories should a 31-year-old woman eat to lose weight?

A 31-year-old woman should eat approximately 1475 kcal/day to lose about 0.5 kg (1 lb) per week. This is a 500 kcal deficit from the estimated maintenance of 1975 kcal.

BMR, TDEE and exact calorie targets for weight loss, maintenance and muscle gain at age 31.

Calorie Needs at Age 31 — Average Woman

1436

BMR (at rest)

1723

Sedentary TDEE

1975
Lightly active TDEE

2226

Moderately active

1475

Weight loss target

1975

Maintenance

2275

Muscle gain target

How Many Calories Does a 31-Year-Old Woman Need?

Using the Mifflin-St Jeor equation with average US height and weight for a woman aged 31, the resting metabolic rate (BMR) is approximately 1436 kcal/day. With typical daily activity included, total calorie expenditure (TDEE) ranges from 1723 kcal (sedentary) to 2477 kcal (very active).

Age 31 note: Metabolism remains strong through your late twenties. This is the best window to build lean muscle mass — it raises your resting BMR long-term.

Calorie Targets by Goal

Goal	Daily Calories	Expected Result
🔵 Aggressive weight loss	1225 kcal	~0.75 kg/week
📉 Weight loss	1475 kcal	~0.5 kg/week
✅ Maintenance	1975 kcal	Weight stable
💪 Lean bulk	2275 kcal	~0.25 kg/week
🏋️ Aggressive bulk	2475 kcal	~0.5 kg/week

Calorie Needs by Activity Level

Activity Level	Description	Daily Calories
Sedentary	Desk job, minimal movement	1723 kcal
Lightly active	1–3 workouts/week	1975 kcal
Moderately active	3–5 workouts/week	2226 kcal
Very active	Hard training 6–7 days/week	2477 kcal

How Metabolism Changes Around Age 31

Metabolic rate declines approximately 1–2% per decade after age 30, driven primarily by muscle loss (sarcopenia) rather than any inherent slowdown. At age 31, your BMR of 1436 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 31
21	1486 kcal	+50 kcal
26	1461 kcal	+25 kcal
31	1436 kcal	—
36	1411 kcal	-25 kcal
41	1386 kcal	-50 kcal

Macronutrient Split at 1975 kcal

Macro	% of Calories	Grams/day	Calories
Protein	30%	148 g	592 kcal
Carbohydrates	40%	198 g	792 kcal
Fat	30%	66 g	594 kcal

At age 31, 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 31-year-old woman need per day?A lightly active 31-year-old woman of average size needs approximately 1975 kcal/day to maintain weight. This ranges from 1723 kcal (sedentary) to 2477 kcal (very active).

How many calories should a 31-year-old woman eat to lose weight?Aim for 1475 kcal/day — a 500 kcal deficit from the 1975 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 31 affect how many calories you burn?Yes. Every decade after 30, BMR drops ~1–2% mainly due to muscle loss. At age 31 the estimated BMR is 1436 kcal — compare to 1441 kcal at age 30. Resistance training largely offsets this decline.

Related Age Guides

Sources

WHO CDC Mifflin-St Jeor (PubMed)