Health Tools
Adult BMI, BMR and TDEE Estimate Calculator
Calculate BMI from height and weight, estimate resting energy with the Mifflin–St Jeor equation, and multiply by an activity factor for a TDEE scenario—not a diagnosis or calorie prescription.
Adults 20–78 · screening and estimates
Calculate three different health metrics
BMI is a screening ratio; BMR is an equation prediction; TDEE is an activity scenario.
Calculated result
Screening and energy estimates
BMI formula—
Resting equation—
Activity scenario—
Selected BMI interpretation set
| BMI kg/m² | Label |
|---|
Quick answer
How are BMI, BMR and TDEE calculated, and what do they mean?
BMI = kilograms ÷ metres squared. This page's BMR is a resting-energy prediction from the Mifflin–St Jeor equation, and TDEE is BMR multiplied by an activity factor. The values are screening measures or estimates, not a diagnosis or nutrition prescription.
How to use this tool
- Choose the Mifflin–St Jeor equation constant, then enter age 20–78, height, and weight
- Choose an illustrative activity factor for the TDEE scenario and the BMI interpretation set
- Calculate, read the limitations with the result, and export Print, Excel, PDF, or TXT if needed
How the calculation works
Input is limited to adults aged 20–78 to match the adult-category and source-equation boundary. BMI is shown to two decimals; BMR/TDEE are rounded to whole kcal/day. Users can read either standard adult BMI categories or WHO public-health action points for Asian populations, which do not replace international classifications or assess individual risk.
Examples
| Example | Input | Expected result |
|---|---|---|
| Legacy defaults | |
BMI 20.20, BMR 1,461 kcal/day, TDEE scenario 2,265 kcal/day |
| BMI formula | |
BMI 22.86 kg/m² |
| Activity factor | |
TDEE scenario 1,800 kcal/day |
Limitations
- For adults aged 20–78 only; adult BMI categories must not be applied to children or teenagers
- BMI does not distinguish fat, muscle, bone, fat distribution, pregnancy, or individual body differences
- The Mifflin–St Jeor equation uses two constants derived from the original study's female/male groups and may not represent every sex, gender identity, physiology, or medical condition
- Activity factors are illustrative scenarios, not a direct TDEE measurement or a standalone calorie prescription
- Results are not medical, nutrition, or weight-loss advice
Frequently asked questions
Can BMI diagnose health or body fat?
No. BMI is a screening measure based on weight relative to height. A clinician may consider history, examination, laboratory findings, body composition, and other factors for a fuller assessment.
Why do international categories and Asian action points differ?
WHO retained international categories but identified 23.0, 27.5, 32.5, and 37.5 as possible public-health action points for Asian populations because BMI, body fat, and risk relationships vary. These points are not an individual diagnosis.
Are BMR and TDEE the energy I actually use?
No. BMR is a predicted resting-energy value from an equation developed in a study sample. TDEE multiplies it by a general activity factor, so both can differ materially from measured energy expenditure and real behaviour.
Can this be used for children, teenagers, pregnancy, or illness?
No. This page is limited to adults aged 20–78. Children and teens require age- and sex-specific BMI interpretation, while pregnancy, illness, medication, and treatment goals need individualized professional assessment.
References
- CDC — Adult BMI Categories Verified 2026-07-31
- PubMed — Mifflin et al. resting energy equation (1990) Verified 2026-07-31
- WHO Expert Consultation via PubMed — BMI action points for Asian populations Verified 2026-07-31
Content and calculation method last reviewed: