Calorie Calculator
The calorie calculator estimates how many calories your body needs each day based on your age, gender, height, weight, and activity level. It uses the Mifflin-St Jeor equation — the most accurate BMR formula available — to find your Basal Metabolic Rate (calories burned at complete rest) and then multiplies by your activity factor to get your Total Daily Energy Expenditure (TDEE).
How to Use
- Choose male or female.
- Enter age, height, and weight with the correct unit toggles.
- Select the activity level that describes a normal week.
- Press Calculate to see BMR, TDEE, and calorie targets.
- Use the chart to compare loss, maintenance, gain, and BMR.
Formula
Male BMR = 10×W + 6.25×H − 5×A + 5
Female BMR = 10×W + 6.25×H − 5×A − 161
W is weight in kg, H is height in cm, and A is age. TDEE = BMR × activity factor. Mifflin-St Jeor is widely preferred over the older Harris-Benedict equation because Harris-Benedict can overestimate needs by about five percent. The common 500 calorie deficit rule uses the estimate that 1 kg of body fat stores roughly 7700 kcal, so a 500 kcal daily deficit is about 3500 kcal weekly and roughly 0.45 to 0.65 kg per week for many people.
Worked Example
30-year-old male, 75 kg, 175 cm, moderately active: BMR = 10(75) + 6.25(175) − 5(30) + 5 = 1698.75. TDEE = 1698.75 × 1.55 = 2633 kcal/day. Weight loss target = 2633 − 500 = 2133 kcal/day.
Calorie Content of Common Foods
| Food | Serving | Calories |
|---|---|---|
| Idli (1 piece) | 40g | 39 kcal |
| Dosa (plain) | 100g | 168 kcal |
| Chapati | 35g | 104 kcal |
| Cooked rice | 150g | 195 kcal |
| Dal (moong) | 100g | 105 kcal |
| Chicken breast | 100g | 165 kcal |
| Egg (boiled) | 50g | 78 kcal |
| Banana | 120g | 107 kcal |
Practical Guide
Calorie Calculator is meant to be more than a bare input form. It gives a result, shows related values, and explains the method so the number can be checked. Calorie and TDEE calculations are easiest to trust when every input is labelled, units are consistent, and the assumptions are visible. This page keeps the arithmetic in your browser and does not submit personal values to a server.
The first practical step is to enter values that match the labels exactly. A centimetre field should not receive inches, a kilogram field should not receive pounds unless the toggle is changed, and a date field should use the calendar date that the formula asks for. The calculator converts units internally where a toggle exists, then rounds the displayed result to a sensible level.
The second practical step is to read the supporting values. The main answer is useful, but the extra cards, visual scale, reference table, and FAQ often explain why the result moved. When you change one input, compare the before and after result. Sensitivity checks make mistakes easier to spot and help you understand which variable matters most.
The third practical step is to treat estimates as planning tools. Real bodies, calendars, clocks, public holidays, and schedules have variation. A formula can be correct and still need interpretation for a specific person, workplace, school, or event. Use the result as a structured starting point, then adjust for your actual trend, local policy, or professional advice.
Rounding avoids false precision. JavaScript calculates with full numeric precision, but the display uses whole calories, one decimal place, whole days, or clock minutes when that is more readable. If you need medical, legal, payroll, government, or contractual certainty, confirm the answer with the official source that governs your situation.
Very low calorie diets can be unsafe without medical supervision, especially during pregnancy, illness, adolescence, or heavy training.
For repeated use, save the inputs that represent your normal case and recalculate when something changes. Calorie Calculator is especially useful when you compare scenarios: lower and higher activity, a different date range, another time zone, or a new goal. That comparison is often more valuable than a single isolated answer.
FAQ
What is BMR?
Basal metabolic rate is the energy your body uses at rest.
What is TDEE?
Total daily energy expenditure estimates full daily calorie burn after activity.
How many calories to lose 1 kg?
About 7700 kcal is a common estimate.
Does age affect calorie needs?
Yes, BMR usually declines with age.
Is 1200 calories too low?
For many adults it can be too low to meet nutritional needs.
Interpretation Checklist
Before using the result, confirm that the input values match the question you are actually trying to answer. Many mistakes happen because the arithmetic is correct but the starting assumption is wrong: a current weight is entered instead of a goal weight, a local date is used where a cutoff date is required, a clock time is converted without considering the target city, or a holiday is counted even though the organization works that day. Reading the input labels slowly is the simplest way to prevent those errors.
Next, compare the result with a rough mental estimate. A calorie target should be within a realistic human range, a due date should be close to forty weeks from the LMP method, a working-day count should be lower than the total calendar days, and a Unix timestamp should map to the expected year. These quick checks do not replace the calculator, but they catch misplaced decimals, reversed dates, wrong units, and accidental future or past values.
Then decide whether the answer is an exact rule or an estimate. Leap-year logic, timestamp conversion, and time addition are deterministic calculations. Calorie needs, body fat percentage, water intake, sleep quality, walking calories, and heart-rate zones are estimates based on formulas and assumptions. Date planning sits in the middle: arithmetic can be exact, but holidays, policies, and regional observances may change the practical interpretation.
Finally, record the result with the inputs that produced it. A saved number without context is hard to audit later. Write down the date calculated, units used, selected mode, and any optional setting such as activity level, resting heart rate, embryo age, excluded weekends, or selected holiday list. This makes the result easier to explain, compare, and update when circumstances change.
Use this page for fast, transparent calculation and education. For decisions involving medical treatment, pregnancy care, employment eligibility, payroll, contracts, official holidays, retirement benefits, or legal deadlines, verify the final answer against the authority that controls that decision. The calculator is designed to make the arithmetic clear; the final responsibility is to apply the correct real-world rule.