# Weight & Mass Converter

- **URL:** https://codeasystem.com/calculators/conversion/weight-mass-converter/
- **Category:** conversion
- **Description:** Convert weights between milligrams, grams, kilograms, tonnes, ounces, pounds, stone and US tons using exact internationally agreed factors.
- **Primary output:** Conversion: 10 pounds = 4.53592 kilograms

## Inputs
- Value (name: `value`, type: number, example: 1)
- From (name: `from`, type: select)
- To (name: `to`, type: select)

## Outputs
- Conversion: 10 pounds = 4.53592 kilograms
- In grams: 4,535.9237
- In ounces: 160
- In stone: 0.714286
- 1 pounds equals: 0.453592 kilograms

## Formula / methodology
```
result = value × factor(from) ÷ factor(to)
Exact anchors: 1 lb = 0.45359237 kg, 1 oz = 28.349523125 g
```

Each amount converts to kilograms using internationally agreed exact constants; the 1959 agreement fixes the pound at 0.45359237 kg and the ounce at one sixteenth of that; then divides by the destination unit’s factor.

## Assumptions & limitations
- Results are rounded only for display; full precision is used internally.
- Conversions use exact standard definitions of each unit.

## How to use
1. **Enter the weight**; Any positive number works, from milligram recipes to tonne freight.
2. **Set the units**; Pick the source unit and the target unit from the dropdowns.
3. **Compare common units**; Alongside your conversion, see grams, kilograms, ounces and pounds equivalents.

## Example
A 10 lb bag of flour weighs about 4.536 kg on a metric scale.

Result for these inputs:

```
Conversion: 10 pounds = 4.53592 kilograms
```

## About this calculator
### Pounds, stone and kilos

Britons quote body weight in stone (14 lb), Americans in pounds, and most of the world in kilograms. One stone is 6.35029318 kg; knowing your own weight in all three makes international conversations instant.

### Mass versus weight

Strictly, kilograms measure mass while pounds-force measure weight under gravity. Everyday converters treat them interchangeably at Earth’s surface, where the distinction never changes a recipe or a shipping quote.

### Cooking across borders

Recipes mix ounces with grams constantly. Since one ounce is exactly 28.349523125 g, converting a 12 oz bag of chocolate gives about 340 g; which is exactly what European packaging prints.

## FAQs
### Is a UK long ton included?

No; the “US ton” here is the short ton of 2,000 lb (907.18474 kg). The 2,240 lb long ton survives mostly in UK shipping history.

### How do I convert stone to pounds quickly?

Multiply stone by 14 mentally, or use the tool: 11 st equals 154 lb exactly.

### Are carats or troy ounces supported?

Not in this tool; those are gemstone and precious-metal units with different definitions from ordinary avoirdupois ounces.

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Last updated: 2026-08-23 · Version: 1.0.0 · [HTML version](https://codeasystem.com/calculators/conversion/weight-mass-converter/)