Calorie calculator
Free calorie calculator for adult maintenance energy. Estimate resting calories and activity-adjusted kcal per day with clear formulas and limitations.
By Calcr · Updated
Free calorie calculator for adult maintenance energy
Estimate resting energy expenditure and an activity-adjusted maintenance scenario in kilocalories per day. This free calorie calculator uses the Mifflin–St Jeor equation with your age, weight, height and selected equation coefficient, then multiplies by an assumed activity factor. It does not prescribe food intake, calculate a weight-loss deficit or promise a future body weight.
Enter measurements and choose assumptions
Choose metric kilograms and centimetres or US pounds and total inches. Enter age in completed years. This implementation supports ages 19–78, the range studied in the original paper, rather than extending the equation to children or an unlimited age range. A valid number inside that range still does not prove that the estimate suits your individual circumstances.
The original model has male and female coefficients. The form names those coefficients explicitly rather than treating them as a complete description of a person's physiology or identity. If neither model is appropriate to your clinical situation, a health professional can help choose a suitable assessment. You do not need to enter your name, date of birth or contact details.
Calorie calculator formula
For weight W in kilograms, height H in centimetres and age A in years, the simplified resting-energy equations are:
- Male coefficient: 10W + 6.25H - 5A + 5.
- Female coefficient: 10W + 6.25H - 5A - 161.
- Activity-adjusted scenario: resting estimate * selected multiplier.
The equations come from Mifflin and colleagues' original 1990 study. They predict resting expenditure from measurements; they are not a direct measurement of your metabolism. The activity multipliers below are additional assumptions used by this calculator and were not derived as personalized activity measurements in that paper.
| Selected activity assumption | Multiplier |
|---|---|
| Mostly seated | 1.2 |
| Light activity | 1.375 |
| Moderate activity | 1.55 |
| High activity | 1.725 |
| Very high activity | 1.9 |
These labels help compare scenarios. They are not a validated questionnaire that identifies your exact multiplier from a workout count. Daily movement, occupation and training can vary, and an activity estimate can be the largest source of uncertainty in the final number. Avoid choosing the highest factor simply because one demanding session occurred.
Worked maintenance-calorie examples
Resting and mostly seated estimates
For a 30-year-old using the male coefficient at 70 kg and 175 cm, the resting equation is 700 + 1093.75 - 150 + 5 = 1648.75 kcal/day. Multiplying by 1.2 gives 1978.5, displayed as 1979 kcal/day. The resting and activity-adjusted numbers answer different questions; the smaller one is not a recommended eating target.
A different coefficient and body size
For age 40, weight 60 kg, height 165 cm and the female coefficient, resting expenditure is 600 + 1031.25 - 200 - 161 = 1270.25 kcal/day. With the light-activity assumption of 1.375, the scenario is 1746.59375, displayed as 1,747 kcal/day. Keep the unrounded resting value during multiplication; rounding it first can slightly change the final display.
Comparing activity assumptions
Return to the first example and change only the multiplier from 1.2 to 1.55. The resting estimate remains 1648.75, while the activity-adjusted result becomes 2555.5625, displayed as 2,556 kcal/day. This difference comes entirely from an assumption. It is not evidence that the person's actual expenditure changed or that a specific exercise burned the difference.
When to use this calculator, and when not to use it
Use it to learn how a resting-energy equation works or to compare transparent maintenance scenarios before discussing them with a qualified professional. Write down the selected coefficient, multiplier and measurement units along with any saved result. A bare number of calories hides assumptions that are necessary to interpret it.
Do not use this estimate for pregnancy, breastfeeding, childhood, medical nutrition therapy or eating-disorder management. This page also does not assess symptoms, medication effects, recovery from illness or unusual energy needs. The NIDDK Body Weight Planner's scope information likewise distinguishes adult planning from use during pregnancy or breastfeeding; its dynamic model is different from this simple equation.
Maintenance expenditure and a weight-change plan are different tasks. Subtracting an arbitrary amount from the result does not make a safe or individually appropriate diet. Changes in body weight are not modeled here, and the calculator does not forecast a timeline. A repeat calculation with the same measurements simply repeats the same assumptions. It is not a follow-up assessment and cannot show whether a food plan or treatment has worked. If food or weight tracking is distressing, you can stop using the tool and seek support suited to your circumstances.
FAQ
Does the result tell me exactly how much to eat?
No. It is an equation-based scenario with an assumed activity level. Actual needs may differ, and a recommended intake requires individual context. The display is rounded to a whole kilocalorie for readability, but that arithmetic precision should not be mistaken for certainty about a person's daily requirements.
Is resting energy the same as total daily energy?
No. The resting estimate is the starting value predicted by the equation. The larger activity-adjusted estimate applies a selected multiplier to approximate a broader daily scenario. This tool labels the two separately. It does not measure either quantity directly, and it does not ask you to use the resting number as a food limit.
Which activity multiplier should I choose?
Choose an assumption that represents the scenario you are examining, and compare nearby factors if you are uncertain. A single workout does not fully describe a typical day or week. The form's labels are broad guides rather than a personal assessment. A dietitian or clinician can help interpret activity and energy needs in a relevant context.
Can I use this for weight loss or muscle gain?
The tool supplies maintenance scenarios only. It does not set a deficit, surplus, target weight or treatment plan. Training, medical history and nutritional needs require more context than the form collects. Do not infer that following the displayed number guarantees a particular change in weight or body composition.
Why does switching units change my result slightly?
Equivalent measurements produce the same underlying calculation after conversion. Rounding a converted weight or height can alter the inputs, which may change the displayed result by a small amount. Check that US height is entered in total inches, not a feet-and-inches decimal. A large difference usually calls for reviewing units before interpreting the energy estimate.
Related tools and guides
For reference only. This page does not provide medical or nutritional advice, diagnosis, treatment or an individualized calorie prescription.