Weight Converter

Last verified: July 2026

Convert weight and mass measurements between metric and imperial units. Features real-world scale comparisons and step-by-step arithmetic.

Min: 0 kgMax: 150 kg
Quick Weight Presets (Milestones)
ALL CONVERSION RESULTS
Micrograms
1,000,000,000 mcg
Milligrams
1,000,000 mg
Grams
1,000 g
Kilograms
1 kg
Metric
0.001 t
Ounces
35.273962 oz
Pounds
2.204623 lb
Stones
0.157473 st
US
0.001102 ton
Imperial
0.000984 lton
Closest Reference ScaleStandard Laptop

1 kg is approximately 6.67x of a medium apple

Logarithmic Milestone Gauge
Medium AppleStandard Laptop
How is this calculated? (View worked mathematical solution)

All conversions map inputs to the base metric unit (kilograms) and then distribute across target scales using exact NIST conversion factors:

Step 1: Convert input value to SI base unit (kilograms):

kg = 1 kg Γ— 1 (conversion factor) = 1 kg

Step 2: Convert base kilograms to other target units:

Micrograms (mcg): 1 kg / 1e-9 = 1,000,000,000 mcg
Milligrams (mg): 1 kg / 0.000001 = 1,000,000 mg
Grams (g): 1 kg / 0.001 = 1,000 g
Kilograms (kg): 1 kg / 1 = 1 kg
Metric (t): 1 kg / 1000 = 0.001 t
Ounces (oz): 1 kg / 0.028349523125 = 35.273962 oz
Pounds (lb): 1 kg / 0.45359237 = 2.204623 lb
Stones (st): 1 kg / 6.35029318 = 0.157473 st
US (ton): 1 kg / 907.18474 = 0.001102 ton
Imperial (lton): 1 kg / 1016.0469088 = 0.000984 lton
Methodology, Constants & NIST Standards

Our weight and mass conversions rely exclusively on official standardized coefficients:

  • International Yard and Pound Agreement of 1959: Standardized standard weight measurements across English-speaking countries. Defines the pound to exactly 0.45359237 kilograms.
  • US Short Ton vs. Imperial Long Ton: A US short ton is defined as exactly 2,000 pounds (907.18 kg), whereas a British long ton is exactly 2,240 pounds (1016.05 kg).
  • Stone (st) standard: Standardized in Great Britain under the Weights and Measures Act of 1835 as exactly 14 pounds (approx. 6.35 kilograms).

About the Weight Converter

Weight and mass are fundamental properties in physical science and everyday measurement. While mass is an intrinsic property measuring the quantity of matter in an object, weight is a variable force representing the gravitational pull acting on that mass. In daily language, these terms are used interchangeably. To standardize measurements, the modern world uses the metric system (SI) based on decimal divisionsβ€”ranging from micrograms and milligrams to grams, kilograms, and metric tonnes. Simultaneously, the imperial and US customary systems rely on historically defined units such as ounces, pounds, stones, and short/long tons. Converting between these systems is essential in clinical medicine dosage calculation, aviation luggage limits, international shipping commerce, and culinary recipes.

Mathematical Formula & Logic

Weight and mass conversions utilize precise mathematical constants standardized by international standard systems: 1. Pounds to Kilograms: kg = lb Γ— 0.45359237 2. Kilograms to Pounds: lb = kg / 0.45359237 (or lb β‰ˆ kg Γ— 2.20462262) 3. Ounces to Grams: g = oz Γ— 28.349523125 4. Grams to Ounces: oz = g / 28.349523125 (or oz β‰ˆ g Γ— 0.03527396) 5. Stones to Pounds: lb = st Γ— 14 6. Metric Tonnes to Kilograms: kg = t Γ— 1000

Step-by-Step Example

Convert a patient's body weight of 176 pounds to kilograms and stones: 1. Identify the variables: - Pounds (lb) = 176 2. Convert to kilograms using the standard conversion factor: kg = lb Γ— 0.45359237 kg = 176 Γ— 0.45359237 kg β‰ˆ 79.8283 3. Convert pounds to stones (1 stone = 14 lbs): st = 176 / 14 st β‰ˆ 12.5714 (or 12 stones and 8 lbs) 4. Therefore, 176 lbs is approximately 79.83 kg or 12.57 stones.

Reference Data & Values

unit namesystempound equivalentkg equivalent
Milligram (mg)Metric0.0000022 lb0.000001 kg
Gram (g)Metric0.00220 lb0.001 kg
Kilogram (kg)Metric2.20462 lb1.000 kg
Metric Tonne (t)Metric2204.62262 lb1000 kg
Ounce (oz)Imperial0.06250 lb0.02835 kg
Pound (lb)Imperial1.00000 lb0.45359 kg
Stone (st)Imperial14.00000 lb6.35029 kg

Frequently Asked Questions

Mass is the amount of matter in an object and is constant regardless of location (measured in kilograms). Weight is the force of gravity acting on that mass and changes depending on gravity (measured in Newtons). For instance, an astronaut with a mass of 80 kg has the same 80 kg mass on Earth and the Moon, but weighs 784 N on Earth and only 130 N on the Moon.
The imperial system contains three distinct "tons": the Short Ton (primarily used in the US) is exactly 2,000 lbs (907.18 kg); the Long Ton (traditionally used in the UK) is exactly 2,240 lbs (1,016.05 kg); and the Metric Tonne (t) is exactly 1,000 kg (approximately 2,204.62 lbs). It is critical to distinguish which ton is being referenced in logistics and heavy freight shipping.
The stone is a historical unit of mass that originated in antiquity, based on the use of actual stones as counterweights in local trade. It was standardized in the United Kingdom and Ireland under the Weights and Measures Act of 1835 to be exactly 14 pounds. It remains a common unit for expressing human body weight in the UK and Commonwealth countries.
To approximate pounds to kilograms mentally, divide the value by 2 and then subtract 10% from the result. For example, 100 lbs divided by 2 is 50. Subtracting 10% (5) yields 45 kg (which is very close to the exact conversion of 45.36 kg).
Historically, the definition of a pound differed slightly between standardizing institutions in different countries. In 1959, standardizing bodies from the United States, United Kingdom, and Commonwealth nations signed the International Yard and Pound Agreement. This treaty resolved all discrepancies by establishing a single, universally standardized value defined to exactly eight decimal places relative to the physical standard kilogram.
A microgram is one-millionth of a gram (1e-6 g) or one-billionth of a kilogram (1e-9 kg). It is a standard unit in clinical pharmacology for measuring extremely potent medications or hormone doses (such as thyroid hormones or fentanyl), where precise micro-measurements are required to prevent toxicity.
There are exactly 16 ounces (avoirdupois ounces) in one standard pound. A single ounce is mathematically equivalent to exactly 28.349523125 grams.
A US short ton is exactly 2,000 pounds (907.18 kg), whereas a metric ton (or tonne) is exactly 1,000 kilograms (approximately 2,204.62 pounds). Therefore, a metric ton is about 10.2% heavier than a US short ton.