BMR Calculator · Practical guide
BMR for a 40 Year Old Woman
Depending on build, a 40-year-old woman burns roughly 1,170 to 1,600 calories a day at rest.
At a glance
The Short Answer
Using the Mifflin-St Jeor equation, a 40-year-old woman of average build — 65 kg (143 lb) and 163 cm (5'4") — has a BMR of about 1,308 kcal/day. Across common heights and weights the range runs from roughly 1,170 to 1,600 kcal.
Interactive tool
BMR Calculator
Enter your own values, then compare the result with the examples below.
Daily Calorie Needs by Activity
| Activity Level | Multiplier | Calories / Day |
|---|---|---|
| Sedentary (little/no exercise) | 1.2 | -- |
| Lightly active (1-3 days/week) | 1.375 | -- |
| Moderately active (3-5 days/week) | 1.55 | -- |
| Very active (6-7 days/week) | 1.725 | -- |
| Super active (physical job/training) | 1.9 | -- |
BMR at Four Common Builds
| Build | BMR (kcal/day) |
|---|---|
| 55 kg / 157 cm (121 lb, 5'2") | 1,170 |
| 65 kg / 163 cm (143 lb, 5'4") | 1,308 |
| 75 kg / 170 cm (165 lb, 5'7") | 1,452 |
| 85 kg / 178 cm (187 lb, 5'10") | 1,602 |
How Age Fits In
The equation subtracts 5 kcal for every year of age, so the same woman burns about 50 fewer calories per day at 40 than she did at 30 — and will burn 50 fewer again at 50, at unchanged weight and height. That gradual drift is why calorie targets set years ago quietly stop working.
From BMR to a Real Eating Target
Resting burn is only the starting point. A sedentary 40-year-old with a 1,308 kcal BMR needs about 1,570 kcal/day total (×1.2); with moderate exercise 3-5 days a week, about 2,027 kcal (×1.55). For weight loss, eat 250-500 kcal below that total — not below the BMR itself. Enter your own stats in the calculator above for exact figures.
Frequently Asked Questions
What is a good BMR for a 40-year-old woman?
There is no good or bad BMR — it simply reflects body size. A higher BMR usually means a larger or more muscular body, which also needs more food to maintain.
Why is my BMR lower than it was at 30?
The equation models a 5 kcal/day drop per year, driven mainly by gradual muscle loss. Strength training slows that decline but does not stop it entirely.
How many calories should a 40-year-old woman eat to lose weight?
Calculate your TDEE (BMR × activity factor) and eat 250-500 kcal below it. For a sedentary woman with a 1,308 BMR, that is roughly 1,070-1,320 kcal — work with a professional before going near the low end.
Does menopause change BMR?
Hormonal shifts around menopause can lower metabolic rate beyond the standard age effect and change fat distribution, so recalculate your numbers if weight or composition changes noticeably.