Calorie Calculator
Find your daily calorie target to lose, maintain, or gain weight.
This calorie calculator turns your body stats and goal into a single, actionable number: how many calories to eat each day. It first estimates the calories you burn (your maintenance level, or TDEE), then adjusts up or down for the rate of weight change you choose — so you get a target for losing, maintaining, or gaining weight.
Everything runs in your browser, so your measurements never leave your device. The result shows your target alongside your maintenance calories and BMR, plus the weekly weight change your target implies, so the number is never a black box.
📖 Read the guide: How Many Calories Should I Eat? A Simple Guide
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Formula
BMR (Mifflin–St Jeor)
BMR = 10·kg + 6.25·cm − 5·age (+5 male / −161 female)
Basal Metabolic Rate is the energy your body uses at complete rest. The Mifflin–St Jeor equation is the modern standard and is more accurate for most people than the older Harris–Benedict formula.
Maintenance calories (TDEE)
TDEE = BMR × activity factor (1.2 sedentary … 1.9 very active)
Total Daily Energy Expenditure scales your BMR by how active you are. Eating at your TDEE keeps your weight roughly stable.
Goal target
target = TDEE ± (rate in lb/week × 3,500 ÷ 7)
A pound of body fat stores about 3,500 calories, so a 500 kcal/day deficit targets ≈ 1 lb of loss per week. The calculator never recommends below a safe daily minimum (1,500 kcal for men, 1,200 for women).
How to use the calorie calculator
- 1Choose your sex and units, then enter your age, weight, and height.
- 2Pick the activity level that best matches a typical week — be honest, as most people overestimate.
- 3Choose a goal (lose, maintain, or gain) and, if losing or gaining, a rate of 0.5–2 lb per week.
- 4Read your daily calorie target, along with your maintenance (TDEE) and BMR for context.
Examples
| Example | Input | Result |
|---|---|---|
| Lose weight | M, 30y, 80kg, 180cm, moderate, 1 lb/wk | ≈ 2,259 kcal/day |
| Maintain | Same person | ≈ 2,759 kcal/day |
| Gain weight | Same person, +0.5 lb/wk | ≈ 3,009 kcal/day |
How many calories should you eat?
There is no single right number — it depends on your size, age, sex, activity, and goal. The honest starting point is your maintenance level (TDEE): the calories you burn on an average day. Eat at maintenance and your weight holds steady; eat consistently below it and you lose weight; eat above it and you gain. This calculator estimates that maintenance level with the Mifflin–St Jeor equation, then shifts it by the amount needed for your chosen rate of change.
Because the estimate is built from population averages, treat the target as a well-informed starting point, not a guarantee. Your real needs are influenced by muscle mass, genetics, sleep, stress, and the fidgeting and non-exercise movement researchers call NEAT, which can vary daily energy use by hundreds of calories.
Calorie deficit and surplus, safely
To lose weight you need a calorie deficit — eating fewer calories than you burn. A moderate deficit of about 500 calories a day targets roughly one pound of fat loss per week, which is sustainable for most people and helps preserve muscle. Larger deficits lose weight faster but are harder to stick to and risk muscle loss, fatigue, and nutrient gaps, which is why this tool clamps the target to a safe daily floor.
To gain weight — usually muscle — you need a modest surplus. A surplus of 250–500 calories a day supports steady gains while limiting fat accumulation. Pair either goal with adequate protein and resistance training: the calculator sets the energy target, but what you eat and how you train decides whether the change is mostly fat or mostly muscle.
Maintenance, BMR, and TDEE explained
Three numbers describe your energy: BMR is what you would burn lying in bed all day; TDEE (maintenance) adds the energy of moving, working, and exercising; and your target is TDEE adjusted for your goal. Seeing all three makes the trade-offs clear — a small daily deficit looks tiny next to your TDEE, yet it adds up to meaningful change over weeks.
If your goal is body composition rather than just weight, pair this with the Body Fat Calculator to track fat versus lean mass, and use the BMI Calculator for a quick height-to-weight screen. Recalculate every few weeks as your weight changes, since a lighter body burns fewer calories and your target should come down with it.
This calculator provides general estimates for educational use and is not medical or nutritional advice. Calorie needs vary by individual. Consult a doctor or registered dietitian before starting a weight-loss or weight-gain plan, especially if you have a health condition.
Frequently asked questions
How many calories should I eat to lose weight?
Aim for roughly 500 calories a day below your maintenance level (TDEE) to lose about a pound a week. Enter your details above and choose “Lose weight” for a personalised target — it won't drop below a safe minimum of 1,500 kcal for men or 1,200 for women.
What's the difference between this and a TDEE calculator?
A TDEE calculator tells you your maintenance calories. This calorie calculator goes a step further: you pick a goal and a rate of change, and it returns the specific daily target to hit it, plus the weekly weight change that implies.
Is a 500-calorie deficit right for everyone?
It's a sensible default, but smaller people or those close to their goal may do better with a 250-calorie deficit. Larger or very active people can sometimes handle more. Track your weight over 2–3 weeks and adjust.
Why did my target stop going down when I picked a faster rate?
The calculator won't recommend an unsafe intake. If your chosen rate would push the target below the safe daily minimum, it raises the number to that floor and notes it — losing faster than that should be done under professional supervision.
Does this calculator store my information?
No. Every calculation runs locally in your browser — nothing you enter is uploaded, logged, or stored on a server.
Embed this calculator
Add the Calorie Calculator to your own website — free. Copy and paste this snippet:
<iframe src="https://numvella.com/embed/calorie-calculator" width="100%" height="460" style="border:1px solid #e2e8f0;border-radius:12px" title="Calorie Calculator — Numvella" loading="lazy"></iframe>Related calculators
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