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Weight Converter

Our free volume & weight converter handles weight conversions. See tables, ratios, and examples for quick reference.

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Unit Conversion

Weight Converter

Convert between 12 weight and mass units including kilograms, pounds, ounces, stone, tonnes, grains, carats, and troy ounces. Instant comprehensive weight conversion.

Last updated: December 2025

Calculator

Adjust values & calculate
100 Kilograms
100 kg = 220.4624 lb

All Conversions

Milligrams (mg)100,000,000
Grams (g)100,000
Kilograms (kg)100
Metric Tonnes (t)0.1
Ounces (oz)3,527.399
Pounds (lb)220.462
Stone (st)15.747
US Short Tons0.11
Imperial Long Tons0.098
Grains (gr)1,543,236.074
Carats (ct)500,000
Troy Ounces (ozt)3,215.072
Your Result
100 Kilograms = 100 kg = 220.4624 lb
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Understand the Math

Formula

Target = Value x (Source g factor / Target g factor)

All weight conversions pass through grams as the base unit. Each unit has a fixed factor to grams: 1 kg = 1000 g, 1 lb = 453.592 g, 1 oz = 28.3495 g, 1 st = 6350.29 g. To convert between any two units, multiply the input by its gram factor, then divide by the target gram factor.

Last reviewed: December 2025

Worked Examples

Example 1: Gold Weight Conversion

Convert 5 troy ounces of gold to grams and regular ounces.
Solution:
Grams: 5 x 31.1035 = 155.5175 g Kilograms: 155.5175 / 1000 = 0.1555 kg Avoirdupois ounces: 155.5175 / 28.3495 = 5.4857 oz
Result: 5 troy oz = 155.52 g = 5.49 regular oz

Example 2: Shipping Weight

A package weighs 35 pounds. Convert to kilograms and ounces.
Solution:
Kilograms: 35 x 0.453592 = 15.8757 kg Grams: 15,875.72 g Ounces: 35 x 16 = 560 oz
Result: 35 lb = 15.88 kg = 560 oz
Expert Insights

Background & Theory

The Weight Converter applies the following established principles and formulas. Unit conversion is the process of expressing a quantity in a different unit of measurement while preserving its physical meaning. At the foundation of modern measurement lies the International System of Units (SI), which defines seven base units: the meter for length, kilogram for mass, second for time, ampere for electric current, kelvin for thermodynamic temperature, mole for amount of substance, and candela for luminous intensity. All other units, called derived units, are defined as algebraic combinations of these seven. Dimensional analysis is the principal method for performing unit conversions. By treating units as algebraic quantities that can be multiplied, divided, and cancelled, a conversion factor chain allows a value expressed in one unit to be rewritten in another without altering its physical magnitude. For example, to convert 60 miles per hour to meters per second, one multiplies by a chain of conversion factors each equal to one: (1609.34 m / 1 mile) ร— (1 hour / 3600 s). Metric prefixes enable compact expression of quantities across extreme ranges of magnitude. Standard prefixes span from nano (10^-9) through micro (10^-6) and milli (10^-3) up through kilo (10^3), mega (10^6), and giga (10^9), and beyond in both directions. These prefixes are strictly multiplicative and apply consistently to any SI base or derived unit. Temperature conversions require affine transformations rather than simple scaling. To convert Celsius to Fahrenheit the formula is ยฐF = (ยฐC ร— 9/5) + 32, while the conversion to the absolute Kelvin scale is K = ยฐC + 273.15. These formulas reflect the different zero points and degree-size conventions of each scale. Significant figures govern how precision is preserved through calculations. A result should not express more precision than the least precise input value permits. In digital storage, IEEE and IEC standards distinguish between decimal prefixes (kilobyte = 1000 bytes) and binary prefixes (kibibyte = 1024 bytes), a distinction that has practical consequences for how storage capacity is reported by manufacturers versus operating systems. Unit coherence โ€” ensuring that all quantities in an equation share a consistent unit system โ€” is essential for obtaining correct results.

History

The history behind the Weight Converter traces back through the following developments. Human beings have been measuring and comparing quantities since before recorded history. The earliest known measurement units were body-based: the cubit (the distance from elbow to fingertip), the foot, the hand, and the digit. The furlong originated as the length of a furrow a team of oxen could plow without resting. These anthropomorphic standards were practical for local use but differed between regions and kingdoms, creating persistent difficulties in trade and construction. The ancient Egyptians standardized the royal cubit at approximately 52.4 centimeters and distributed calibrated granite rods to ensure consistency across building projects, including the pyramids. Roman engineers used the mile (mille passuum, one thousand double paces) and spread these standards throughout their empire via road networks. Despite these efforts, measurement diversity persisted across medieval Europe, hampering commerce. The French Revolution created political will for radical standardization. In 1795 France officially adopted the metric system, defining the meter as one ten-millionth of the distance from the equator to the North Pole along the Paris meridian. This gave the world its first fully decimal, rationally constructed measurement system. The Metre Convention of 1875 established the International Bureau of Weights and Measures (BIPM) in Sevres, France, creating a permanent international body to maintain physical artifact standards and coordinate global metrology. For over a century, the kilogram was defined by a platinum-iridium cylinder locked in a vault near Paris. In 1999, a stark demonstration of what unit inconsistency costs occurred when NASA's Mars Climate Orbiter was lost because one engineering team used pound-force seconds while another used newton seconds. The spacecraft entered the Martian atmosphere at the wrong angle and was destroyed, at a cost of 327 million dollars. In 2019 the SI underwent its most significant revision, redefining all seven base units in terms of fixed numerical values of fundamental physical constants such as the speed of light, Planck's constant, and the elementary charge. This eliminated any reliance on physical artifacts and made the measurement system permanently stable and universally reproducible.

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Frequently Asked Questions

Mass measures the amount of matter in an object and is measured in kilograms, while weight is the gravitational force on that mass and is technically measured in newtons. On Earth, a 1 kg mass weighs about 9.81 newtons. In everyday language, mass and weight are used interchangeably since all measurements are taken on Earth. The distinction becomes important in physics and space travel where gravitational fields differ.
The key conversion factors are: 1 kg = 2.20462 lb, 1 lb = 0.453592 kg, 1 oz = 28.3495 g, and 1 stone = 14 lb = 6.35029 kg. For quick mental math, double kilograms and add 10% to get pounds, or halve pounds and subtract 10% to get kilograms. This converter handles all these conversions automatically for twelve different weight units including specialized units like carats and grains.
You may use the results for reference and educational purposes. For professional reports, academic papers, or critical decisions, we recommend verifying outputs against peer-reviewed sources or consulting a qualified expert in the relevant field.
All calculations use established mathematical formulas and are performed with high-precision arithmetic. Results are accurate to the precision shown. For critical decisions in finance, medicine, or engineering, always verify results with a qualified professional.
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.
The Formula section on this page shows the equation used. You can reproduce the calculation manually or in a spreadsheet using those steps. Compare your answer against the worked examples in the Examples section, which use known reference values so you can confirm the calculator is behaving as expected.
Educational Note: This calculator is provided for educational and informational purposes. Results are based on the formulas and inputs provided. Always verify important calculations independently. NovaCalculator processes calculator inputs client-side; optional analytics follow visitor consent settings. ยฉ 2024โ€“2026 NovaCalculator.

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Formula

Target = Value x (Source g factor / Target g factor)

All weight conversions pass through grams as the base unit. Each unit has a fixed factor to grams: 1 kg = 1000 g, 1 lb = 453.592 g, 1 oz = 28.3495 g, 1 st = 6350.29 g. To convert between any two units, multiply the input by its gram factor, then divide by the target gram factor.

Worked Examples

Example 1: Gold Weight Conversion

Problem: Convert 5 troy ounces of gold to grams and regular ounces.

Solution: Grams: 5 x 31.1035 = 155.5175 g\nKilograms: 155.5175 / 1000 = 0.1555 kg\nAvoirdupois ounces: 155.5175 / 28.3495 = 5.4857 oz

Result: 5 troy oz = 155.52 g = 5.49 regular oz

Example 2: Shipping Weight

Problem: A package weighs 35 pounds. Convert to kilograms and ounces.

Solution: Kilograms: 35 x 0.453592 = 15.8757 kg\nGrams: 15,875.72 g\nOunces: 35 x 16 = 560 oz

Result: 35 lb = 15.88 kg = 560 oz

Frequently Asked Questions

What is the difference between mass and weight?

Mass measures the amount of matter in an object and is measured in kilograms, while weight is the gravitational force on that mass and is technically measured in newtons. On Earth, a 1 kg mass weighs about 9.81 newtons. In everyday language, mass and weight are used interchangeably since all measurements are taken on Earth. The distinction becomes important in physics and space travel where gravitational fields differ.

How do I convert between metric and imperial weight units?

The key conversion factors are: 1 kg = 2.20462 lb, 1 lb = 0.453592 kg, 1 oz = 28.3495 g, and 1 stone = 14 lb = 6.35029 kg. For quick mental math, double kilograms and add 10% to get pounds, or halve pounds and subtract 10% to get kilograms. This converter handles all these conversions automatically for twelve different weight units including specialized units like carats and grains.

How accurate are the results from Weight Converter?

All calculations use established mathematical formulas and are performed with high-precision arithmetic. Results are accurate to the precision shown. For critical decisions in finance, medicine, or engineering, always verify results with a qualified professional.

How do I interpret the result?

Results are displayed with a label and unit to help you understand the output. Many calculators include a short explanation or classification below the result (for example, a BMI category or risk level). Refer to the worked examples section on this page for real-world context.

Can I use Weight Converter on a mobile device?

Yes. All calculators on NovaCalculator are fully responsive and work on smartphones, tablets, and desktops. The layout adapts automatically to your screen size.

How do I verify Weight Converter's result independently?

The Formula section on this page shows the equation used. You can reproduce the calculation manually or in a spreadsheet using those steps. Compare your answer against the worked examples in the Examples section, which use known reference values so you can confirm the calculator is behaving as expected.

References

Reviewed by Manoj Kumar, Mathematics Educator ยท Editorial policy