Use this free BMR calculator and TDEE calculator to estimate resting energy burn and daily maintenance calories from height, weight, age, sex, and activity level. Enter height in centimeters, weight in kilograms, and age in years, then choose male or female. The Mifflin St Jeor equation plus an activity multiplier run entirely in your browser. Results are shown in kilocalories per day (kcal/day) for adults aged 18 and older. This is not medical advice or a prescription for diet or training.
Yaya Tools’ maintenance calories calculator answers two linked questions: how many calories your body would burn at complete rest (BMR), and how many calories you roughly need across a typical day once movement is included (TDEE). Those numbers help frame meal planning and weight-change goals, but they remain population-based estimates. Individual metabolism, medical conditions, medications, and body composition can shift real needs.
What is BMR/TDEE?
Basal metabolic rate (BMR) is an estimate of the energy your body uses to keep basic life processes going: breathing, circulation, cell repair, and temperature regulation while you are completely at rest. It is the largest piece of daily energy expenditure for most adults who are not highly active. A BMR calculator does not measure heat output in a lab. It predicts BMR from easy anthropometric inputs using a validated equation.
Total daily energy expenditure (TDEE) is BMR scaled up by how much you move. Sitting at a desk all day multiplies BMR by a smaller factor than a job with heavy physical labor or intense training. A TDEE calculator therefore needs both a BMR estimate and an activity factor. The product is often called maintenance calories: if you eat roughly that many calories over time, weight tends to stay about the same, all else equal.
On this page, BMR and TDEE work together:
- BMR — resting kcal/day from Mifflin–St Jeor using weight, height, age, and sex
- Activity factor — sedentary (1.2), light (1.375), moderate (1.55), high (1.725), or very high (1.9)
- TDEE — BMR × activity factor, reported as kcal/day
Together they give a practical starting point for calorie awareness. They do not replace a calorimetry test, a registered dietitian’s plan, or clinical nutrition counseling.
Who is this calculator designed for?
The tool is intended for adults aged 18 and older. Mifflin–St Jeor equations used here are adult formulas; they are not growth-chart tools for children or teens. Pregnant or breastfeeding people, people recovering from illness or surgery, and anyone with a metabolic, endocrine, or eating-disorder history should rely on clinician guidance rather than a web estimate alone.
If you need to confirm that someone meets the adult age threshold before interpreting results, the age calculator can compute exact years, months, and days from a birth date.
Body size context also matters. A BMI calculator can show how weight relates to height on a screening scale. BMR/TDEE then estimates energy needs for that same adult body. Use BMI for category screening and BMR/TDEE for calorie estimates. Each answers a different question.
How to use the BMR/TDEE calculator
The workflow is short so you can check maintenance calories during a food log setup or before adjusting intake.
- Open the BMR/TDEE calculator on Yaya Tools.
- Enter height in centimeters.
- Enter weight in kilograms.
- Enter age in years (adults 18+).
- Select sex: male or female (the Mifflin–St Jeor constant differs by sex).
- Choose an activity level that best matches a typical week, not your most active day.
- Read BMR and TDEE in kcal/day. Results update as inputs change.
Pick the activity factor honestly. Overestimating activity is one of the most common reasons a “maintenance” target feels too high and weight slowly rises.
Privacy and local processing
Height, weight, age, sex, and activity are calculated only in your current browser tab. Nothing is sent to a server, stored in a Yaya Tools account, or synced across devices by this page. That local-only design suits quick personal checks. On shared computers, remember that browser autofill, history, and extensions can still expose typed values.
Choosing an activity factor
| Activity level | Factor | Typical pattern |
|---|---|---|
| Sedentary | 1.2 | Desk work, little or no exercise |
| Light | 1.375 | Light exercise or sports 1–3 days/week |
| Moderate | 1.55 | Moderate exercise or sports 3–5 days/week |
| High | 1.725 | Hard exercise or sports 6–7 days/week |
| Very high | 1.9 | Very hard daily exercise or physical job |
These multipliers are conventional Harris–Benedict / Mifflin-era activity factors used widely in online TDEE calculator tools. They are approximate bands, not personalized wearables data. If your job is sedentary but you train hard a few evenings, many people start near moderate and adjust after a few weeks of weighing trends rather than jumping straight to very high.
Formulas
Yaya Tools uses the Mifflin–St Jeor equation for BMR, then multiplies by the selected activity factor for TDEE. Units are metric: weight in kilograms, height in centimeters, age in years. Output is kilocalories per day.
Mifflin–St Jeor BMR
Male
BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years) + 5
Female
BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years) − 161
The structure is the same for both sexes; only the final constant changes (+5 vs −161). That constant is why sex selection matters even when weight, height, and age are identical.
TDEE from activity
TDEE = BMR × activity factor
Activity factors on this page:
Sedentary = 1.2
Light = 1.375
Moderate = 1.55
High = 1.725
Very high = 1.9
Why Mifflin–St Jeor?
Several equations estimate resting metabolism. Mifflin–St Jeor (published in 1990) is widely recommended for healthy adults in nutrition practice because it tends to track measured resting energy expenditure reasonably well in modern populations compared with older Harris–Benedict versions. It still remains an estimate. Athletes with high muscle mass, older adults with sarcopenia, and people with altered thyroid function may need clinical assessment beyond any public bmr calculator.
If you want to sanity-check percentages—for example, “what is 80% of my TDEE for a cut?”—the percentage calculator can apply those ratios without rewriting the whole energy equation.
Examples
Worked examples use the exact formulas above. Displayed tools may round to whole kcal/day; intermediate arithmetic is shown for clarity.
Example 1: Male, moderate activity — 175 cm, 70 kg, age 30
BMR = 10×70 + 6.25×175 − 5×30 + 5
= 700 + 1093.75 − 150 + 5
= 1648.75 kcal/day
Moderate activity factor = 1.55:
TDEE = 1648.75 × 1.55 ≈ 2555.6 kcal/day
Interpretation: resting needs are about 1649 kcal/day; with moderate weekly activity, maintenance calories land near 2556 kcal/day.
Example 2: Female, light activity — 162 cm, 58 kg, age 28
BMR = 10×58 + 6.25×162 − 5×28 − 161
= 580 + 1012.5 − 140 − 161
= 1291.5 kcal/day
Light activity factor = 1.375:
TDEE = 1291.5 × 1.375 ≈ 1775.8 kcal/day
Interpretation: BMR near 1292 kcal/day; light activity maintenance near 1776 kcal/day.
Example 3: Male, sedentary — 180 cm, 90 kg, age 45
BMR = 10×90 + 6.25×180 − 5×45 + 5
= 900 + 1125 − 225 + 5
= 1805 kcal/day
Sedentary factor = 1.2:
TDEE = 1805 × 1.2 = 2166 kcal/day
Interpretation: a larger body raises BMR, but a sedentary multiplier keeps TDEE lower than the same BMR under high activity. Choosing sedentary vs high changes maintenance calories more than many people expect.
Example 4: Female, high activity — 168 cm, 65 kg, age 35
BMR = 10×65 + 6.25×168 − 5×35 − 161
= 650 + 1050 − 175 − 161
= 1364 kcal/day
High activity factor = 1.725:
TDEE = 1364 × 1.725 ≈ 2352.9 kcal/day
Interpretation: BMR about 1364 kcal/day; with hard exercise most days, estimated maintenance is about 2353 kcal/day. If training volume drops for weeks, recompute with a lower factor rather than keeping the peak-week multiplier indefinitely.
Comparing two activity levels for the same person
Take Example 1’s male BMR of 1648.75 kcal/day:
| Activity | Factor | TDEE (approx.) |
|---|---|---|
| Sedentary | 1.2 | 1979 kcal/day |
| Moderate | 1.55 | 2556 kcal/day |
| Very high | 1.9 | 3133 kcal/day |
Same body, same Mifflin St Jeor BMR—yet maintenance estimates differ by more than a thousand calories between sedentary and very high. That spread is why activity honesty matters more than tweaking height by a centimeter.
Common mistakes
Treating TDEE as a fixed medical truth. Equations average population patterns. Your true maintenance may sit hundreds of calories above or below the estimate. Use weight trends over 2–4 weeks to refine.
Inflating the activity factor. Choosing “very high” because of one hard workout day while living a desk week overstates TDEE. Match the usual week.
Confusing BMR with TDEE. BMR is rest-only. Eating only at BMR while remaining active is a large deficit for many people and is not automatically “safe” or recommended. This page reports both so you can see the difference.
Using the tool for children or teens. Adult Mifflin–St Jeor constants and activity bands do not replace pediatric energy equations or clinical growth assessment.
Ignoring measurement units. The formulas expect kg and cm. Entering pounds or inches without converting produces nonsense BMR values.
Assuming sex is optional. Male and female Mifflin–St Jeor formulas differ by 166 kcal in the constant term alone (+5 vs −161). Wrong sex selection shifts every result.
Equating maintenance calories with a diet plan. TDEE is an energy estimate. Protein targets, micronutrients, medical restrictions, and food quality are separate decisions.
Expecting server-side history. Local processing means the page does not store past entries. Save numbers yourself if you track over time.
Replacing professional care. Rapid weight loss, unexplained weight gain, fatigue, or disordered eating symptoms need licensed healthcare support—not a calculator tweak.
Forgetting body composition. Two adults with the same weight and height can have different muscle mass and slightly different true resting needs. Pair calorie estimates with the BMI calculator for size context, and with clinical measures when decisions matter.
Sources and methodology
The BMR estimate is based on the Mifflin–St Jeor equations published in the original peer-reviewed study, “A new predictive equation for resting energy expenditure in healthy individuals” (American Journal of Clinical Nutrition, 1990). That study derived the equations from measured resting energy expenditure in 498 healthy adults aged 19–78.
TDEE on this page multiplies the BMR estimate by conventional activity factors. Those labels are rough planning categories, not measurements from the Mifflin–St Jeor study and not a clinical prescription. Individual energy needs can differ because of body composition, health, medication, environment, and actual activity. Indirect calorimetry and qualified clinical assessment are more appropriate when accuracy affects medical or nutrition treatment.