How many calories should I eat to lose weight?

Your daily calorie target depends on your age, sex, height, weight, and activity level. This calculator computes your TDEE (Total Daily Energy Expenditure) and subtracts a deficit based on your chosen pace. A typical weight loss target is 500 kcal below your TDEE, which results in roughly 0.45 kg (1 lb) of weight loss per week.

How do you calculate weight loss percentage?

Weight loss percentage = ((Starting Weight − Current Weight) ÷ Starting Weight) × 100. For example, going from 90 kg to 81 kg is a 10% weight loss. A 5-10% loss is considered clinically significant for health benefits like reduced blood pressure and improved blood sugar control.

Is losing 2 pounds a week too fast?

Losing 2 pounds (about 1 kg) per week is at the upper end of what most health organizations consider safe. It requires a daily deficit of about 1,000 kcal. For most people, 1-1.5 pounds (0.5-0.7 kg) per week is more sustainable and carries less risk of muscle loss. People with more weight to lose can safely lose at a faster rate initially.

How long will it take to lose 20 pounds?

At a moderate pace of 1 pound per week, it takes about 20 weeks (5 months) to lose 20 pounds. At 1.5 pounds per week, it takes roughly 13-14 weeks. Use this calculator with your specific details for a more accurate, personalized timeline that accounts for your metabolism and activity level.

What is a safe calorie deficit for weight loss?

A safe deficit is typically 500-750 kcal per day, which produces 0.5-0.75 kg (1-1.5 lb) of weekly weight loss. Deficits over 1,000 kcal/day are not recommended without medical supervision. Women should not go below 1,200 kcal/day and men below 1,500 kcal/day, as this can cause nutrient deficiencies and metabolic slowdown.

Does exercise speed up weight loss?

Yes, exercise increases your TDEE, which means you burn more calories daily. This allows you to eat more while maintaining a deficit, or lose weight faster at the same calorie intake. Select a higher activity level in the calculator to see the impact. Strength training is especially valuable as it helps preserve muscle mass during weight loss.

Why does weight loss slow down over time?

As you lose weight, your body requires fewer calories to function (lower BMR), so your TDEE decreases. This means the same calorie intake produces a smaller deficit over time. This is called metabolic adaptation. To continue losing weight, you may need to reassess your calorie target periodically using this calculator with your updated weight.

What are macros and why do they matter for weight loss?

Macros (macronutrients) are protein, fat, and carbohydrates. For weight loss, a higher protein intake (around 30% of calories) helps preserve muscle mass and keeps you feeling full. This calculator recommends a 30/25/45 split (protein/fat/carbs) optimized for weight loss while maintaining energy for daily activities.

Weight Loss Calculator

Sex

Age

Height

Current Weight

Goal Weight (kg)

13 kg to lose

Activity Level

Weight Loss Pace

Estimated Goal Date

Nov 14, 2026

13 kg0.5 kg/wk~6 months15.3%

Daily Calorie Plan

Your personalized calorie target for weight loss

Daily Calorie Target

2,190kcal

Daily Deficit

550kcal

Milestones

Key checkpoints on your weight loss journey

25%

81.8 kg

Week 7

50%

78.5 kg

Week 13

75%

75.3 kg

Week 20

100%

72 kg

Week 26

Daily Macronutrients

Optimized macro split for weight loss (30/25/45)

164g

Protein

61g

Fat

246g

Carbs

Understanding Your Numbers

Your BMR, TDEE, and how far you are from your goal

BMR

1,768

Calories at rest

TDEE

2,740

Maintenance calories

Weight Loss %

15.3%

Of body weight

Total to Lose

13 kg

To reach goal

How the Weight Loss Calculator Works

A 3-step process: BMR, then TDEE, then your deficit target

This calculator uses the Mifflin-St Jeor equation to estimate your Basal Metabolic Rate (BMR) — the number of calories your body burns at rest. It then multiplies your BMR by an activity factor to determine your Total Daily Energy Expenditure (TDEE).

Calculate your BMR

Using the Mifflin-St Jeor equation, we calculate the calories your body burns at complete rest — breathing, circulation, and cell production.

Men: BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) + 5

Women: BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) − 161

Calculate your TDEE

Your BMR is multiplied by an activity factor (1.2× to 1.9×) based on your exercise habits. This gives your maintenance calories.

Apply your deficit

Based on your pace or deadline, we subtract the required deficit from your TDEE to give you a daily calorie target. Since ~7,700 kcal = 1 kg of body fat, the math is precise.

How to Calculate Weight Loss Percentage

The formula doctors use to measure clinically significant weight loss

Weight loss percentage tells you what proportion of your original body weight you've lost. It's more meaningful than raw pounds because it accounts for body size.

The formula:

Weight Loss % = ((Starting Weight − Current Weight) ÷ Starting Weight) × 100

Example:

If you weigh 200 lb and your goal is 170 lb:

((200 − 170) ÷ 200) × 100 = 15% weight loss

Doctors consider a 5-10% weight loss clinically significant for improving blood pressure, blood sugar, and cholesterol levels.

Understanding Calories and Weight Loss

How energy balance determines whether you lose, maintain, or gain weight

Weight loss fundamentally comes down to energy balance. When you consume fewer calories than your body burns, it taps into stored energy (primarily body fat) to make up the difference.

500

kcal/day deficit

≈ 0.45 kg (1 lb) / week

750

kcal/day deficit

≈ 0.68 kg (1.5 lb) / week

1,000

kcal/day deficit

≈ 0.9 kg (2 lb) / week

Your TDEE depends on your BMR and activity level. Activity multipliers range from 1.2× (sedentary) to 1.9× (extra active). More physical activity increases your TDEE, allowing a larger deficit without reducing food intake as drastically.

Activity multiplier reference:

Sedentary (desk job, no exercise)1.2×

Lightly active (1-3 days/week)1.375×

Moderately active (3-5 days/week)1.55×

Very active (6-7 days/week)1.725×

Extra active (physical job + exercise)1.9×

Safe Weight Loss: How Fast Is Too Fast?

Guidelines from medical organizations on sustainable, healthy weight loss rates

Most health organizations recommend losing 0.5 to 1 kg (1-2 lb) per week. Faster rates increase the risk of muscle loss, nutrient deficiencies, gallstones, and metabolic slowdown.

Recommended

0.5-1 kg (1-2 lb) per week
500-750 kcal/day deficit
Preserves muscle mass
Sustainable long-term

Risky

>1 kg (2+ lb) per week sustained
Below 1,200 kcal (women) / 1,500 kcal (men)
Risk of gallstones and nutrient deficiency
Metabolic slowdown and rebound

Key safety guidelines:

Protein matters: 0.7-1g per pound of body weight helps preserve muscle during a deficit
Sustainability wins: Moderate deficits are easier to maintain and lead to better long-term outcomes than crash diets
Metabolic adaptation: Your metabolism slows as you lose weight — reassess your calorie target periodically

This calculator enforces safety minimums and shows warnings when your selected pace creates an excessively aggressive deficit. Always consult a healthcare professional before starting a weight loss plan.

Frequently Asked Questions

Common questions and detailed answers

Embed Weight Loss Calculator

Add this calculator to your website or blog for free.

Related calculators from other categories

Last updated Apr 2, 2026

Weight Loss Calculator

Daily Calorie Plan

Milestones

Daily Macronutrients

Understanding Your Numbers

How the Weight Loss Calculator Works

How to Calculate Weight Loss Percentage

Understanding Calories and Weight Loss

Safe Weight Loss: How Fast Is Too Fast?

Frequently Asked Questions

Embed Weight Loss Calculator

You Might Also Like