📌 Based on the Mifflin-St Jeor equation — the most accurate BMR formula for most people.

About the Calorie Calculator

Calories are the fundamental currency of nutrition. Eat more than you burn and you gain weight; eat less and you lose it. But 'how many calories do I need?' isn't a one-size-fits-all answer — it depends on your age, sex, height, weight, and how active you are day-to-day.

Our Calorie Calculator combines your Basal Metabolic Rate (BMR) with your activity level to produce your Total Daily Energy Expenditure (TDEE) — the number of calories you need to maintain your current weight. It then shows you adjusted targets for gradual weight loss, fast weight loss, or weight gain, so you can set a goal that's actually achievable.

How It Works

We use the Mifflin-St Jeor equation to calculate BMR, then multiply by your activity factor to get TDEE. Weight loss and gain targets are then calculated using standard caloric deficit and surplus thresholds, based on the widely accepted rule that 1 lb of fat ≈ 3,500 calories.

Formula / Key Reference

TDEE = BMR × Activity Multiplier

Goal-based calorie targets:

Maintain weight: TDEE

Lose 0.5 lb/week: TDEE − 250 cal
Lose 1 lb/week: TDEE − 500 cal
Lose 1.5 lb/week: TDEE − 750 cal

Gain 0.5 lb/week: TDEE + 250 cal

Gain 1 lb/week: TDEE + 500 cal

Real-World Example

Person: Female, 28 years old, 163 cm, 70 kg, lightly active (walks daily, no gym)

BMR = (10 × 70) + (6.25 × 163) − (5 × 28) − 161
= 700 + 1,018.75 − 140 − 161

= 1,417.75 calories

TDEE (lightly active × 1.375): 1,417.75 × 1.375 ≈ 1,949 calories/day

Weight loss targets:

Lose 0.5 lb/week: 1,699 calories/day

Lose 1 lb/week: 1,449 calories/day

This tells her that eating around 1,449 calories per day — without changing her activity — should produce steady, safe weight loss of about 1 lb per week.

Common Uses

  • Building a personalized nutrition plan for weight loss or muscle gain
  • Setting a calorie budget that matches your lifestyle and activity level
  • Adjusting intake after weight changes or activity level changes
  • Planning macronutrient splits (protein, carbs, fat) from your calorie target
  • Comparing the calorie impact of different activity levels

Frequently Asked Questions

Are calorie calculators accurate? ▼
They are estimates. The Mifflin-St Jeor formula has been validated in clinical research and is accurate within ±10% for most people. Individual factors like gut microbiome, hormones, genetics, and medication can cause real-world deviations. Use the calculator as a starting point and adjust based on 2–4 weeks of actual results.
What is the minimum safe calorie intake? ▼
Most health authorities recommend no fewer than 1,200 calories per day for women and 1,500 for men, even when losing weight aggressively. Going below these thresholds risks nutritional deficiencies and muscle loss. A deficit of 500 calories per day is considered safe and sustainable.
Should I eat back exercise calories? ▼
This depends on your activity multiplier. If you already set your activity level to 'moderately active,' your exercise calories are already included in your TDEE. Only add calories back if you are using the 'sedentary' setting and then exercising on top.
How long will it take to lose 20 lbs? ▼
At a deficit of 500 calories per day (1 lb/week), losing 20 lbs takes approximately 20 weeks, or about 5 months. At 750 calories/day deficit, it's roughly 13 weeks. Sustainable fat loss slows as you lose weight because your BMR decreases, so recalculate your TDEE every 10 lbs lost.