Height & Weight Converter – Convert Feet, Inches, cm, kg, lb & BMI Online

Introduction

In a highly connected world, understanding different systems of measurement is more important than ever. Whether you are traveling abroad, speaking with an international doctor, tracking your fitness journey, or simply buying clothes online, you will frequently encounter the need to convert measurements.

A Height & Weight Converter is an essential tool designed to bridge the gap between the Metric system (used by the vast majority of the world) and the Imperial system (used primarily in the United States, the UK, and a few other nations). This comprehensive guide is designed to be the ultimate resource for understanding height and weight conversions. We will explore how these conversions work, provide accurate formulas, break down real-world examples, and answer every question you might have about biometrics, BMI, and measurement standards.

Featured Snippets (Quick Answers)

How do I convert feet to centimeters?

To convert feet to centimeters, multiply your height in feet by 30.48. For example, 5 feet equals 152.4 centimeters. If you have inches as well, convert the entire height to inches first, then multiply by 2.54.

How do I convert pounds to kilograms?

To convert pounds to kilograms, divide the weight in pounds by 2.20462 (or multiply by 0.453592). For example, 150 pounds divided by 2.20462 equals approximately 68.04 kilograms.

What is BMI?

Body Mass Index (BMI) is a simple mathematical calculation that uses your height and weight to estimate whether you are underweight, at a healthy weight, overweight, or obese. It is a screening tool rather than a direct measurement of body fat.

What is the metric system?

The metric system is an internationally agreed-upon decimal system of measurement. For human body measurements, it primarily uses meters (m) and centimeters (cm) for height, and kilograms (kg) or grams (g) for weight.

Which countries use feet and pounds?

The United States primarily uses feet, inches, and pounds (the US Customary System). The United Kingdom often uses a mix, commonly measuring human height in feet and inches, and weight in stones and pounds, though they officially use the metric system for most other applications. Liberia and Myanmar also use variations of the imperial system.

What Is a Height Converter?

A Height Converter is a mathematical tool or formula used to translate a vertical measurement of the human body from one unit to another. Because height can be expressed in base-10 metric units (like centimeters and meters) or base-12 imperial units (like feet and inches), converting between them requires specific multiplication or division factors. A good height converter eliminates human error, instantly translating a measurement like 180 cm into 5 feet 10.8 inches.

What Is a Weight Converter?

Similarly, a Weight Converter translates body mass from one system to another. Weight in the medical and scientific communities is almost exclusively recorded in kilograms. However, standard household scales in the US read in pounds, and scales in the UK often read in stones and pounds. A weight converter ensures that 70 kg can be seamlessly understood as 154.3 pounds or 11 stone.

Metric vs Imperial System

Understanding the background of these two systems helps explain why conversions are necessary.

The Metric System

Originating in France during the late 18th century, the metric system is a decimal-based system of measurement. It is logical and highly scalable because everything is based on multiples of 10.

• Base Length: Meter
• Base Mass: Gram (Kilogram is the standard base unit in the International System of Units, SI)

The Imperial (US Customary) System

The imperial system has historical roots in medieval England, where measurements were often based on physical objects or body parts (a “foot” was literally the length of a human foot). It is not base-10, making mental math more challenging (e.g., 12 inches in a foot, 16 ounces in a pound).

Common Height Units

• Millimeters (mm): Used in highly precise medical or scientific contexts.
• Centimeters (cm): The most common metric unit for human height.
• Meters (m): Often used alongside centimeters (e.g., 1.75 m).
• Inches (in): The smallest standard imperial unit for height.
• Feet (ft): The primary imperial unit for height.

Common Weight Units

• Grams (g): Used for very light weights, such as neonatal care.
• Kilograms (kg): The global standard for human body weight.
• Ounces (oz): Imperial unit for small increments (16 oz = 1 lb).
• Pounds (lb): The standard unit for body weight in the US.
• Stones (st): A British unit equal to 14 pounds.

Why Accurate Conversion Matters

Accurate height and weight conversions are not just for convenience; they are critical for safety and health.

1. Medication Dosing: Doctors and pharmacists dose strong medications (especially for children and in anesthesia) based on milligrams of medicine per kilogram of body weight. An error in converting pounds to kilograms can lead to dangerous under-dosing or over-dosing.
2. Medical Equipment: MRI machines and surgical tables have strict weight limits.
3. Aviation: Small aircraft require exact weight distributions for safe takeoff and landing.
4. Fitness Tracking: Following international workout plans or diet macros requires understanding the units the author is using.

BMI Overview

Body Mass Index (BMI) is a globally recognized metric created by Adolphe Quetelet in the 19th century. It helps classify populations into weight categories.

The formula for BMI is:

BMI = Weight in kg ÷ (Height in m)²

If using Imperial units, the formula adapts to:

BMI = [Weight in lb ÷ (Height in inches)²] × 703

Standard BMI Categories (WHO):

• Underweight: Less than 18.5
• Normal weight: 18.5 – 24.9
• Overweight: 25.0 – 29.9
• Obesity: 30.0 or higher

Note: BMI does not measure body fat directly. A heavily muscled athlete may have an “overweight” BMI due to muscle mass.

Ideal Body Weight

Ideal Body Weight (IBW) is an estimate used mostly in medical settings (like calculating drug clearances) rather than an aesthetic goal. Several formulas exist, with the Devine Formula being the most common.

Devine Formula (Simplified):

• Men: 50.0 kg + 2.3 kg per inch over 5 feet
• Women: 45.5 kg + 2.3 kg per inch over 5 feet

International Measurement Standards

The International System of Units (SI) governs modern measurement. For biometrics, the SI units are meters for length and kilograms for mass. The World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) utilize these SI units for global health reporting, which is why metric is considered the gold standard for scientific data.

Formulas & Text-Based Diagrams

To convert manually, you need to know the exact multiplication factors.

Height Formulas:

• 1 inch = 2.54 centimeters
• 1 foot = 12 inches = 30.48 centimeters
• 1 centimeter = 0.393701 inches
• 1 meter = 3.28084 feet

Weight Formulas:

• 1 kilogram = 2.20462 pounds
• 1 pound = 0.453592 kilograms
• 1 stone = 14 pounds = 6.35029 kilograms

Conversion Process Diagram

Input Value (e.g., 150 lbs)

↓

Identify Target Unit (e.g., Kilograms)

↓

Apply Conversion Factor (Divide by 2.20462)

↓

Mathematical Calculation (150 ÷ 2.20462)

↓

Converted Result (68.04 kg)

20+ Detailed Worked Examples

Here are 20 step-by-step examples across various life scenarios.

1. 160 cm to Feet

Divide 160 by 30.48. The result is 5.249 feet. To find the inches, take the decimal (0.249) and multiply by 12. Result: 5 feet 3 inches.

2. 175 cm to Feet & Inches

First, divide 175 by 2.54 to get total inches (68.89). Divide 68.89 by 12 to get 5 feet, with a remainder of 8.89 inches. Result: 5 feet 9 inches.

3. 6 Feet to cm

Multiply 6 feet by 30.48 cm per foot. Result: 182.88 cm.

4. 70 kg to Pounds

Multiply 70 by the pound conversion factor of 2.20462. Result: 154.32 pounds.

5. 150 Pounds to kg

Divide 150 by 2.20462. Result: 68.04 kg.

6. 10 Stone to kg

First, convert stones to pounds: 10 × 14 = 140 pounds. Then divide by 2.20462. Result: 63.5 kg.

7. Athlete Example (Boxing Weigh-in)

A boxer weighs in at 147 pounds for a welterweight fight in the US. For the international broadcast, this is converted to metric: 147 ÷ 2.20462 = 66.68 kg.

8. School Student (Health Check)

A school nurse in the UK measures a student at 1.45 meters. For the parents who understand feet: 1.45 m = 145 cm. 145 ÷ 2.54 = 57.08 inches. 57.08 ÷ 12 = 4 feet 9 inches.

9. Hospital Patient (Anesthesia)

An American patient weighing 210 lbs needs surgery. The anesthesiologist requires kilograms. 210 ÷ 2.2046 = 95.25 kg.

10. Fitness Trainer (Setting Goals)

A trainer wants a client to lose 5 kg. The client asks what that means in pounds. 5 × 2.2046 = 11.02 lbs.

11. Nutrition Planning (Macros)

A popular diet recommends 2 grams of protein per kilogram of body weight. An individual weighs 180 lbs. First, find kg: 180 ÷ 2.2046 = 81.6 kg. Then multiply by 2: They need 163.2 grams of protein.

12. Child Growth (Percentiles)

A toddler is 36 inches tall. The doctor charts this on a WHO metric growth chart. 36 × 2.54 = 91.44 cm.

13. Adult Male (Average Height)

The average American male is 5 feet 9 inches. To find cm: (5 × 12) + 9 = 69 inches. 69 × 2.54 = 175.26 cm.

14. Adult Female (Average Height)

The average global female is around 159 cm. In feet and inches: 159 ÷ 2.54 = 62.6 inches. 62.6 ÷ 12 = 5 feet 2.6 inches.

15. Travel Example (Luggage Weight)

An airline in Europe allows a 23 kg checked bag. An American traveler uses a bathroom scale in pounds. 23 × 2.2046 = 50.7 lbs.

16. International Student (Driver’s License)

A European student moves to the US and needs to list height on a license in feet/inches. They are 182 cm tall. 182 ÷ 2.54 = 71.65 inches, which is 5 feet 11.6 inches (usually rounded up to 6’0″).

17. Medical Examination (BMI Calculation)

A patient is 1.70 m tall and weighs 75 kg. BMI = 75 ÷ (1.70 × 1.70) = 75 ÷ 2.89 = 25.9 (Slightly overweight).

18. Military Height Standards

US Army minimum height for males is 60 inches (5 feet). In metric: 60 × 2.54 = 152.4 cm.

19. Aviation Standards (Pilot Requirements)

Some pilot programs require candidates to be between 163 cm and 193 cm. For an American applicant: 163 ÷ 2.54 = 64 inches (5’4″), and 193 ÷ 2.54 = 76 inches (6’4″).

20. Scientific Research (Data Normalization)

A study collects weights from UK (stones), US (lbs), and France (kg). The researcher converts everything to kg for the database. A UK entry of 12 st 4 lbs is calculated: (12 × 14) + 4 = 172 lbs. 172 ÷ 2.2046 = 78.02 kg.

Real-Life Applications

Healthcare and Hospitals

Medical professionals rely exclusively on the metric system. All patient charts, dosages, and medical equipment tolerances are calibrated in kilograms and centimeters to prevent fatal mathematical errors.

Fitness Centers

Globalized fitness equipment, such as treadmills and barbells, often features both metric and imperial options. Powerlifting internationally uses 20 kg and 25 kg plates, while US gyms use 45 lb plates (which equal about 20.4 kg).

Nutrition

Nutritional science is heavily metric. Calories, macronutrients (grams), and micronutrients (milligrams) are standardized. Calculating basal metabolic rate (BMR) accurately requires metric conversions.

Sports

Combat sports (boxing, MMA) often promote weigh-ins in pounds in the US and UK, but use kilograms internationally. Track and field events (like the high jump) record heights in meters.

Schools and Universities

Educational institutions teach the metric system in science classes, but physical education teachers may still use feet and inches depending on the region, requiring students to be adaptable.

International Travel and Immigration

Applying for visas, passports, or international driver’s licenses often requires converting your biometric data to meet the local government’s standard formatting.

Comparison Tables

Metric vs Imperial Overview

Feature	Metric System	Imperial System
Primary Use	Global Standard, Science, Medicine	USA, UK (Partial), Everyday use
Base Height Unit	Meter (m), Centimeter (cm)	Foot (ft), Inch (in)
Base Weight Unit	Kilogram (kg), Gram (g)	Pound (lb), Ounce (oz), Stone (st)
Structure	Base-10 (Decimal)	Mixed / Arbitrary (Base-12, Base-16)

Feet to Meters Comparison

Feet & Inches	Inches	Centimeters	Meters
5′ 0″	60	152.4	1.52
5′ 2″	62	157.5	1.57
5′ 4″	64	162.6	1.63
5′ 6″	66	167.6	1.68
5′ 8″	68	172.7	1.73
5′ 10″	70	177.8	1.78
6′ 0″	72	182.9	1.83
6′ 2″	74	188.0	1.88

Pounds to Kilograms Comparison

Pounds (lb)	Kilograms (kg)	Stones (st)
100	45.36	7 st 2 lb
120	54.43	8 st 8 lb
140	63.50	10 st 0 lb
150	68.04	10 st 10 lb
160	72.57	11 st 6 lb
180	81.65	12 st 12 lb
200	90.72	14 st 4 lb

Frequently Asked Questions (FAQ)

General Unit Conversions

1. How do I use a height and weight converter?

Simply input your known value into the corresponding text box, select the unit you are using, and the tool will instantly output the converted values in all other major systems.

2. Which is better, metric or imperial?

The metric system is universally preferred in science, medicine, and international trade because its base-10 structure makes math simpler and less prone to errors.

3. Why does the US still use the imperial system?

It is deeply ingrained in American culture, manufacturing, and infrastructure. Transitioning to metric (metrication) has been attempted but remains incomplete due to the immense cost and cultural resistance.

4. How accurate are online converters?

Highly accurate. They run on fixed mathematical formulas. Our tool calculates up to several decimal places, ensuring precise biometric translation.

5. How do I round off my height?

For everyday use, height in cm is usually rounded to the nearest whole number. Height in inches is often rounded to the nearest half or whole inch.

6. Are stones used outside the UK?

Rarely. The stone (14 pounds) is primarily used in the UK and Ireland for human body weight.

7. Can I convert height using my phone calculator?

Yes, if you know the formulas (multiply inches by 2.54 for cm, or divide pounds by 2.2046 for kg).

8. What is a conversion factor?

It is a numerical value used to multiply or divide a quantity when converting from one system of units to another.

9. Is there an app for this?

While many apps exist, a web-based converter like ours requires no downloads and works instantly on all devices.

10. What is the difference between mass and weight?

Scientifically, mass is the amount of matter in an object (kg), while weight is the force of gravity on that mass. In everyday language, we use them interchangeably.

Height Specific FAQs

11. How many centimeters are in an inch?

There are exactly 2.54 centimeters in one international inch.

12. How many inches are in a foot?

There are 12 inches in a foot.

13. How many centimeters are in a meter?

There are 100 centimeters in a meter.

14. What is 5’7″ in cm?

5 feet 7 inches is 67 total inches. 67 × 2.54 = 170.18 cm.

15. Is 180 cm tall for a man?

180 cm (about 5’11”) is slightly taller than the global average for men, which is roughly 171 to 175 cm.

16. How do you write feet and inches properly?

Use a single quote for feet and a double quote for inches (e.g., 5′ 10″).

17. Do I need to measure my height barefoot?

Yes, for medical and BMI accuracy, always measure your height without shoes.

18. Why does my height change during the day?

Spinal cartilage compresses throughout the day. You are typically a few millimeters taller in the morning.

19. How do doctors measure height accurately?

Using a stadiometer—a medical device consisting of a vertical ruler and a sliding horizontal headpiece.

20. What is 165 cm in feet?

165 cm is approximately 5.41 feet, which translates to 5 feet 5 inches.

Weight Specific FAQs

21. How many pounds are in a kilogram?

One kilogram is approximately equal to 2.20462 pounds.

22. How many ounces in a pound?

There are 16 ounces in 1 standard pound.

23. What is 75 kg in pounds?

75 × 2.20462 = 165.34 pounds.

24. What is 200 lbs in kg?

200 ÷ 2.20462 = 90.71 kilograms.

25. How do I weigh myself accurately?

Weigh yourself first thing in the morning, after using the restroom, before eating, and without heavy clothing.

26. Why do weightlifting bars say 20 kg but gyms say 45 lbs?

An Olympic barbell is exactly 20 kg (44.1 lbs). Many American gyms round this to 45 lbs for simplicity, though true 45 lb bars (20.4 kg) exist.

27. What is a metric tonne?

A metric tonne is 1,000 kilograms (about 2,204.6 pounds).

28. What is the difference between a short ton and a metric ton?

A US short ton is 2,000 pounds (907 kg), while a metric ton is 1,000 kg (2,204 lbs).

29. Is it better to track weight loss in kg or lbs?

It is a matter of personal preference. Pounds allow you to see smaller numerical drops, which can be motivating, while kg is medically standard.

30. What is 12 stone in pounds and kg?

12 stone is 168 pounds (12 × 14). In kilograms, it is approximately 76.2 kg.

BMI & Ideal Weight FAQs

31. How is BMI calculated?

BMI is calculated by dividing your weight in kilograms by your height in meters squared.

32. What is a healthy BMI?

A healthy BMI is generally considered to be between 18.5 and 24.9.

33. Does BMI account for muscle mass?

No. This is a major limitation of BMI. Muscular individuals may be classified as overweight or obese despite having low body fat.

34. Does BMI account for age or gender?

Standard adult BMI formulas do not account for age or gender, though growth charts for children do.

35. What is the Devine Formula?

It is an equation created in 1974 to estimate ideal body weight for medication dosing based on height and biological sex.

36. Can I be healthy if my BMI is overweight?

Yes. Health is determined by many factors, including blood pressure, cholesterol, lifestyle, and body fat percentage, not just BMI.

37. How do I calculate my child’s BMI?

Children’s BMI is calculated using the same formula but is plotted on a percentile chart based on age and sex, rather than using fixed adult categories.

38. What is body fat percentage?

It is the portion of your total body weight that consists of fat. It is a more accurate indicator of metabolic health than BMI.

39. How do I find my ideal weight?

Ideal weight is subjective and depends on your goals and health status. Medical formulas provide a baseline, but consulting a doctor is best.

40. Why did my BMI change slightly on a different website?

Some websites round height or weight before doing the calculation, or use the imperial formula (× 703) which can cause minor decimal variations.

Medical & Travel FAQs

41. Do I use cm or inches for a UK visa?

The UK generally requests height in centimeters for official immigration documents.

42. Do US hospitals record in pounds or kg?

Most US hospitals record weight in kilograms in their electronic health records to prevent medication errors, though they may tell you your weight in pounds.

43. What is the standard luggage weight for international flights?

Standard economy checked luggage is usually 23 kg (50 lbs). Business class is often 32 kg (70 lbs).

44. How do I report my height for an international driver’s license?

Most international permits require height in centimeters.

45. Why do anesthesiologists need precise kg measurements?

Anesthesia is administered per kilogram of lean body mass. Too much is dangerous; too little causes the patient to wake up.

46. How do pediatricians track growth?

Using percentile charts in cm and kg to compare a child’s growth trajectory against averages.

47. Should I know my biometric data in both systems?

Yes, it is highly recommended if you travel frequently, read international fitness articles, or participate in global events.

48. Are baby birth weights reported in metric or imperial?

In the US, they are reported in pounds and ounces (e.g., 7 lbs 5 oz). Globally, they are reported in grams or kilograms (e.g., 3.3 kg).

49. How do you convert pounds and ounces to kg?

Convert the ounces to a decimal of a pound (divide by 16), add to the pounds, then divide the total by 2.2046. (e.g., 8 lbs 4 oz = 8.25 lbs. 8.25 ÷ 2.2046 = 3.74 kg).

50. Where can I find more health calculators?

Check out our internal links section below for specialized calculators for BMR, body fat, and age.

Authoritative References

For further reading and verification of the standards discussed in this article, please refer to:

• World Health Organization (WHO): Guidelines on BMI and global biometric standards.
• Centers for Disease Control and Prevention (CDC): National health statistics and growth charts.
• National Institute of Standards and Technology (NIST): Official measurement conversions and SI unit definitions.
• International System of Units (SI): Global measurement documentation.

Disclaimer: The information provided in this article and by our converter tool is for educational and informational purposes only. It does not constitute medical advice. Always consult a healthcare professional for diagnosis, treatment, and medical decisions.