Example 1
- BMR = 1650
- age 30
30
What metabolic age at BMR 1650 and age 30? 30. A heuristic, not a lab test.
Metabolic age calculator
Type BMR and age. 1650 and age 30 give 30. 1800 and 35 give 28. 1500 and 40 give 44. The calculator compares your BMR to a 1650 − 5 × (age − 30) sketch, then divides the gap by 25.
Not a clinic verdict and not a lab biological age. The result is a rounded heuristic. You type BMR. The calculator does not compute it.
Results
Enter data and click Calculate.
How it works
Metabolic age in this calculator is age plus (reference BMR minus your BMR) / 25. The reference is 1650 − 5 × (age − 30), clipped to 1150-2100. At BMR 1650 and age 30 the gap is 0, so the result is 30 in the result. 1800 and 35 give 28. 1500 and 40 give 44.
Field a is BMR. Field b is age. The calculator does not run Mifflin. You take BMR from the BMR card or from a label. A higher BMR at the same age drops below chronological age. A lower BMR goes up.
The result is an integer, with no word years on the number. The clamp is 15 to 100. BMR 0, age 0, or BMR above 8000 leaves a dash. This is not a lab test and not a cellular age.
BMR computes a base from weight, height, age, and sex. TDEE multiplies that base by PAL. Here you stay with a ready BMR compared to a simple 1650 line. 28 at 1800 and age 35 is not a younger body from a clinic.
Type BMR, type age, then Calculate. A comma in 1650.5 parses. A sketch from a difference, not a doctor note and not a metabolism test.
1650 and age 30 give 30. 1800 and 35 give 28. 1500 and 40 give 44. Number formatting runs only when Format is present. The examples are a bare rounded number. Metabolic age is a heuristic, not a lab test.
Formula
met_age = round(age + (refBMR − BMR) / 25); refBMR = 1650 − 5 × (age − 30)
How to use
- Type a ready BMR, for example 1650.
- Type age, for example 30.
- Click Calculate. The result is 30.
- 1800 and 35 give 28. 1500 and 40 give 44.
- BMR from weight and height lives on the BMR page. Here only a compare to 1650.
BMR 1650 and age 30 = 30
Age plus (refBMR minus BMR) / 25. 1650 and 30 give 30. A heuristic, not a lab test.
- Metabolic
- An estimate from BMR. 1650 and age 30 show 30. Not a clinic age.
- BMR
- Field a in kcal. 1800 at age 35 gives 28. The calculator does not run Mifflin.
- heuristic
- The 1650 line minus 5 per year from 30. 1500 and age 40 give 44.
Examples
Example 2
- BMR = 1800
- age 35
28
What about BMR 1800 and age 35? 28. A higher BMR steps down.
Example 3
- BMR = 1500
- age 40
44
What about BMR 1500 and age 40? 44. A lower BMR steps up.
Related calculators
Common questions
What metabolic age at BMR 1650 and age 30?
The result is 30. Reference BMR at age 30 is 1650, so the gap is zero and rounding leaves 30.
What about 1800 and age 35?
The result is 28. Reference BMR at age 35 is 1625, so (1625 − 1800) / 25 = −7, and 35 − 7 = 28.
What about 1500 and age 40?
The result is 44. Reference BMR at age 40 is 1600, so (1600 − 1500) / 25 = 4, and 40 + 4 = 44.
Does the calculator compute BMR?
No. The first field takes a ready BMR in kilocalories, without weight or height. The Mifflin–St Jeor formula from those values is on the BMR page.
Is 28 a younger body?
No. A heuristic from the 1650 line. Not a lab age and not a doctor note.
What is the result range?
Rounding, then a clamp from 15 to 100. Above 8000 kcal leaves a dash.
What if BMR is 0 or age is 0?
A dash. BMR and age must be positive.
Does a comma in 1650.5 work?
Yes. 1650.5 and 30 run through the same formula.
Does a US header change 30?
No. BMR and age are not a mass. The result stays the number 30.
Knowledge sources
A heuristic from the BMR you type. The calculator does not compute Mifflin; this is not a lab age.
Page updated in 2026.