BMR Reference for Age 43
Basal metabolic rate at age 43 is not one number — it is a range set by height and weight. This page holds the formula inputs steady at age 43 and sweeps body composition instead: four BMI levels, men at 175 cm and women at 165 cm, each estimated with both Mifflin-St Jeor and Harris-Benedict so the spread between the classic equations is visible at a glance.
The 5 kcal-per-year age term is visible in a single comparison: at 76.6 kg this page lists 1650 kcal, while age 42 lists 1655 — 5 kcal below. The gap between Mifflin-St Jeor and Harris-Benedict on the same row is 60 kcal (3.6%), and the sedentary-to-extra-active span is 1,155 kcal against just 310 kcal of age effect across the whole adult range.
BMR at age 43 by body composition
| BMI | Men (175 cm) | Women (165 cm) | ||||
|---|---|---|---|---|---|---|
| Weight | Mifflin | Harris | Weight | Mifflin | Harris | |
| 20 | 61.3 kg | 1497 kcal | 1505 kcal | 54.5 kg | 1200 kcal | 1277 kcal |
| 25 | 76.6 kg | 1650 kcal | 1710 kcal | 68.1 kg | 1336 kcal | 1402 kcal |
| 30 | 91.9 kg | 1803 kcal | 1915 kcal | 81.7 kg | 1472 kcal | 1528 kcal |
| 35 | 107.2 kg | 1956 kcal | 2120 kcal | 95.3 kg | 1608 kcal | 1654 kcal |
From BMR to daily burn: TDEE at age 43
Multiplying BMR by an activity factor gives total daily energy expenditure. The factors below are the same five levels the main calculator offers, applied to the BMI-25 man from the table (76.6 kg, BMR 1650 kcal):
| Activity level | Factor | TDEE |
|---|---|---|
| Sedentary — little or no exercise | ×1.2 | 1980 kcal/day |
| Lightly active — 1–3 days/week | ×1.375 | 2269 kcal/day |
| Moderately active — 3–5 days/week | ×1.55 | 2558 kcal/day |
| Very active — 6–7 days/week | ×1.725 | 2846 kcal/day |
| Extra active — intense daily training | ×1.9 | 3135 kcal/day |
Get your own figure
Body size matters more than any reference table can capture, so a two-minute personal estimate is usually worth more than a row of averages. Enter your numbers and the box computes the Mifflin-St Jeor result with the same coefficients used across this site:
Frequently asked questions
What is the BMR of a 43-year-old?
It depends on body size as well as age. At age 43, a 175 cm man weighing about 76.6 kg has a Mifflin-St Jeor BMR of roughly 1650 kcal per day, while a 165 cm woman at 68.1 kg lands near 1336 kcal per day. The table above shows how the estimate moves across four common body-composition levels.
Why does BMR fall as age increases?
The Mifflin-St Jeor equation subtracts 5 kcal for every year of age, so between age 20 and age 80 the estimate drops by about 300 kcal per day at the same height and weight. The coefficient is a population average: body composition, not the birthday itself, drives most of the real change.
Mifflin-St Jeor or Harris-Benedict — which should I use?
Mifflin-St Jeor is the default on this site because validation studies found it tracks measured resting energy expenditure more closely for most adults. Harris-Benedict, shown beside it in the table, runs higher for many people — often by 5 to 10 percent — so comparing the two columns is a quick way to see the uncertainty band around any single number.
Nearby ages
Want the full picture — Katch-McArdle from body-fat percentage, the age chart and TDEE in one run? Open the BMRScope calculator or browse every age page.