Weight Converter
Convert between kilograms, grams, pounds, ounces, stones, and tons with instant results.
Conversion Reference
What is Weight Conversion?
Weight conversion is the process of expressing the same mass in different units of measurement. The metric system and the imperial or US customary system developed independently, so converting between them is a routine need in cooking, shipping, fitness, science, and everyday life.
The metric system is based on the kilogram, which is the SI base unit of mass. One kilogram equals exactly 1000 grams, and one metric ton equals 1000 kilograms. Because these relationships are powers of ten, conversions inside the metric system are simple decimal shifts.
The imperial system uses pounds, ounces, and stones. There are exactly 16 ounces in a pound, and one stone equals 14 pounds. One pound is defined as exactly 0.453592 kilograms, which is the bridge value this converter uses to move between the metric and imperial systems.
This tool shows six units at once and keeps them in sync, so you only need to type into a single field. Because weight is proportional, every conversion is a straight multiplication or division by a fixed factor, which means the results are exact up to the displayed rounding.
Key Concepts
- Kilogram — the SI base unit of mass; all factors in this tool are anchored to it.
- Metric prefixes — grams and metric tons differ from kilograms by powers of ten (1000 grams, 0.001 tons).
- Imperial units — pounds, ounces, and stones follow the 16-ounce and 14-pound relationships.
- Bridge factor — 1 pound equals exactly 0.453592 kilograms, linking the two systems.
- Proportional scaling — doubling the input doubles every converted output.
- Live synchronisation — editing any one field recalculates the other five immediately.
How to Use
- Choose an input unit — decide which of the six fields matches the value you already know.
- Enter the weight — type the value into that field, for example 5 in the kilograms box.
- Read the conversions — the other five fields update automatically with the equivalent values.
- Switch the input field — you can type into any field, including pounds, ounces, or stones, at any time.
- Check the reference — use the conversion reference panel to confirm the common factors used.
Weight Conversion Reference
| Unit | Symbol | Kilograms | Notes |
|---|---|---|---|
| Kilogram | kg | 1 | SI base unit of mass |
| Gram | g | 0.001 | One thousandth of a kilogram |
| Pound | lb | 0.453592 | Exactly 16 ounces |
| Ounce | oz | 0.0283495 | One sixteenth of a pound |
| Stone | st | 6.35029 | Exactly 14 pounds, common for body weight |
| Metric ton | t | 1000 | One thousand kilograms |
Worked Examples
- 1 kilogram to pounds — 1 × 2.20462 = 2.20462 lb, which is the anchor for metric-to-imperial conversions.
- 5 kilograms to pounds — 5 × 2.20462 = 11.0231 lb, a typical check weight for baggage.
- 10 pounds to kilograms — 10 × 0.453592 = 4.53592 kg, using the reverse factor.
- 8 ounces to grams — 8 × 28.3495 = 226.796 g, useful for recipe conversions.
- 1 stone to kilograms — 1 stone is 14 pounds, and 14 × 0.453592 = 6.35029 kg.
- 0.5 metric ton to pounds — 0.5 ton is 500 kg, and 500 × 2.20462 = 1102.31 lb.
Tips and Common Mistakes
- Do not confuse mass and weight — kilograms measure mass while pounds are often treated as weight; on Earth the two are used interchangeably in daily life.
- Mind the difference between ton and tonne — this tool uses the metric ton (1000 kg), not the US short ton (about 907 kg) or the UK long ton (about 1016 kg).
- Remember 16 ounces per pound — dividing a pound result by 16 gives ounces, and multiplying ounces by 16 gives pounds.
- Use stone with the 14-pound rule — a body weight of 154 lb is 11 stone exactly, since 154 divided by 14 equals 11.
- Do not round too early — the conversion factors carry several decimals, so round only at the final step to avoid drift.
- Enter numbers only — the fields accept numbers and decimals; entering text or leaving a field blank simply stops the update for that entry.
Common Use Cases
Weight conversions appear constantly across cooking, travel, health, and logistics. Here are some practical situations where this tool saves time and prevents errors.
- Cooking and baking — convert grams to ounces when following recipes written in different measurement systems.
- Travel and baggage — check that luggage falls under airline limits expressed in kilograms or pounds.
- Fitness and health — track body weight in kilograms, pounds, or stones to match a preferred tracking style.
- Shipping and freight — convert between kilograms and metric tons to estimate consignment weights and costs.
- Science and study — switch between SI units and imperial units for lab work, homework, or research notes.
- Online shopping — compare product weights listed in unfamiliar units before buying.
Frequently Asked Questions
How do I convert kilograms to pounds?
Multiply the kilogram value by 2.20462. For example, 5 kg × 2.20462 = 11.0231 lb. To go the other way, multiply pounds by 0.453592.
How many ounces are in a pound?
There are exactly 16 ounces in one pound, which is part of the imperial and US customary systems. So 32 oz equals 2 lb.
What is a stone and where is it used?
A stone is a unit of weight used mainly in the UK and Ireland for body weight. One stone equals 14 pounds or approximately 6.35029 kilograms.
How many grams are in a kilogram?
There are exactly 1000 grams in one kilogram, because the gram is defined as one thousandth of a kilogram. This is a metric relationship, so no bridge factor is needed.
What is the difference between a ton and a tonne?
This tool uses the metric ton, also called a tonne, which equals 1000 kilograms. The US short ton is about 907 kilograms and the UK long ton is about 1016 kilograms.
Why do the converted values show several decimals?
The conversion factors such as 2.20462 and 0.453592 are not whole numbers, so fractional results are expected. The tool computes precisely and you can round the display value yourself.
Can I convert from any unit to any other unit?
Yes. All six units are interlinked through the kilogram, so typing a value into any single field instantly produces the equivalent in the other five.
Is this tool free to use?
Yes. All processing happens entirely in your browser, so no data is sent to any server and you can convert as many values as you like.