How to Calculate Body Weight in KG

Need to know your body weight in kilograms? Whether it's for a medical form, fitness app, or international travel, this complete guide shows you how to convert your body weight from pounds to kilograms and understand what your weight means in the metric system.

The Conversion Formula

kg = lbs × 0.45359237

1 lb = 0.4536 kg
1 kg = 2.2046 lbs

Example: If you weigh 165 lbs:
165 × 0.4536 = 74.843 kg

Quick Weight Conversion

Formula

lbs × 0.4536

= your weight in kg

Divide by 2, subtract 10% for a quick estimate

Convert your exact weight:

Open Converter →

Step-by-Step Guide

Step 1: Weigh Yourself in Pounds

Step on a scale and note your weight in pounds (lbs). For the most accurate reading, weigh yourself in the morning before eating, wearing minimal clothing. Try to use the same scale each time for consistency.

Step 2: Convert Using the Formula

Multiply your weight in pounds by 0.45359237 (or 0.4536 for a quick approximation).

Examples:
130 lbs × 0.4536 = 58.97 kg
150 lbs × 0.4536 = 68.04 kg
180 lbs × 0.4536 = 81.65 kg
200 lbs × 0.4536 = 90.72 kg

Step 3: Understand Your Weight in KG

Now that you have your weight in kilograms, you can use it for medical forms, fitness tracking, medication dosages (which are often calculated per kg of body weight), and international communication where the metric system is standard.

Step 4: Using KG for BMI Calculation

BMI (Body Mass Index) uses kilograms:

BMI = weight (kg) ÷ height (m)²

Example: 75 kg, 1.75 m tall:
BMI = 75 ÷ (1.75 × 1.75) = 75 ÷ 3.0625 = 24.5

BMI Reference Chart

BMI Categories

Underweight: BMI below 18.5
Normal weight: BMI 18.5 - 24.9
Overweight: BMI 25 - 29.9
Obese: BMI 30 or above

Note: BMI is a general guideline and does not account for muscle mass, bone density, or body composition.

Healthy Weight Ranges (Approximate)

5'2" (157 cm): 47 - 63 kg (104 - 139 lbs)
5'5" (165 cm): 50 - 68 kg (111 - 150 lbs)
5'8" (173 cm): 55 - 74 kg (122 - 164 lbs)
5'11" (180 cm): 60 - 81 kg (132 - 179 lbs)
6'2" (188 cm): 65 - 88 kg (144 - 194 lbs)

Based on BMI 18.5 - 24.9 range.

Common Body Weight Conversions

LBS	KG
100	45.36
110	49.9
120	54.43
130	58.97
140	63.5
150	68.04

LBS	KG
160	72.57
170	77.11
180	81.65
190	86.18
200	90.72
220	99.79

LBS	KG
240	108.86
250	113.4
260	117.93
280	127.01
300	136.08
350	158.76

Frequently Asked Questions

How do I calculate my body weight in kg?

Multiply your weight in pounds by 0.4536. For example, if you weigh 160 lbs: 160 × 0.4536 = 72.57 kg.

Why do doctors sometimes ask for weight in kg?

Many medical calculations, including medication dosages and BMI, use kilograms. The metric system is the international standard for medical and scientific measurements.

What is a healthy body weight in kg?

Healthy weight depends on your height. Generally, a BMI between 18.5 and 24.9 is considered normal. For example, a person 170 cm (5'7") tall has a healthy weight range of about 53-72 kg (117-159 lbs).

How do I calculate BMI using kg?

BMI = weight (kg) ÷ height (m)². For example, if you weigh 70 kg and are 1.72 m tall: BMI = 70 ÷ (1.72 × 1.72) = 70 ÷ 2.9584 = 23.7 (normal range).

Should I track my weight in lbs or kg?

Either works for personal tracking. However, kg is preferred for medical purposes, international fitness apps, and scientific contexts. Many fitness professionals recommend kg because the smaller unit changes can be more motivating to track.