Weight & Mass Converter
Mass turns up in recipes, freight dockets, gym plates, postage tables and shipping manifests, and it rarely arrives in the unit you actually want. A parcel might be priced in kilograms, a recipe written in ounces, a body weight quoted in stone, and a bulk order measured in tonnes, yet they all describe the same quantity of matter. This converter lets you enter one value, choose the unit you have and the unit you need, and read the answer immediately, alongside a full reference table that lists your value in every supported unit at once. It covers milligrams, grams, kilograms, tonnes, ounces, pounds and stone, so metric and imperial sit comfortably side by side. The approach is deliberately simple and easy to trust. Every unit is defined by how many kilograms it represents, so the tool multiplies your value by the factor for the unit you are converting from to get a mass in kilograms, then divides by the factor for the unit you want. Because each conversion routes through kilograms as a shared base, a single set of factors handles every possible pairing, and the defined relationships stay exact, such as a pound being precisely 0.45359237 kilograms and an ounce being one sixteenth of that. Strictly speaking these units measure mass rather than weight, but in everyday language the two words are used interchangeably, and the figures behave the same way on Earth. The converter suits cooks scaling recipes, people tracking fitness, online sellers working out postage, importers checking freight, students doing homework, and anyone who wants metric and imperial masses lined up clearly without manual arithmetic.
Your value in every unit
| Unit | Value |
|---|
The formula
Each unit has a factor giving its size in kilograms, the base unit. To convert, multiply the value by the factor of the unit you are converting from, which gives a mass in kilograms, then divide by the factor of the unit you want.
value in kilograms = value × factor[from]
result = value in kilograms / factor[to]
Conversion factors
These are the factors used, each expressed as the number of kilograms in one unit.
| Unit | Kilograms per unit |
|---|---|
| Milligrams | 0.000001 |
| Grams | 0.001 |
| Kilograms | 1 |
| Tonnes | 1000 |
| Ounces | 0.028349523125 |
| Pounds | 0.45359237 |
| Stone | 6.35029318 |
Who this calculator is for
This converter is for cooks, online sellers, importers, people tracking fitness, students and anyone who needs to switch a mass between metric and imperial units quickly and accurately.
What this calculator assumes
- The value you enter is a number; non-numeric characters are ignored.
- Each unit is defined by its size in kilograms, the base unit.
- Conversion passes through kilograms: multiply by the from factor, then divide by the to factor.
- These units measure mass; on Earth they are used interchangeably with weight.
- Results are rounded for display.
Frequently asked questions
How do I convert between weight units?
Multiply your value by the from unit's factor to base kilograms, then divide by the to unit's factor. For example, to turn kilograms into pounds, divide the value in kilograms by 0.45359237, because one pound is 0.45359237 kilograms.
How many pounds are in a kilogram?
One kilogram is about 2.20462 pounds. This comes from dividing 1 by 0.45359237, since a pound is defined as exactly 0.45359237 kilograms.
How many grams are in an ounce?
One ounce is about 28.3495 grams. An ounce is defined as 0.028349523125 kilograms, which is 28.349523125 grams.
What is the difference between weight and mass?
Mass is the amount of matter in an object and does not change with location. Weight is the force gravity exerts on that mass. In everyday use the terms are used interchangeably, and these units all measure mass.
Related calculators
- Length Converter: convert between metric and imperial length units.
- Density Converter: convert mass per unit volume.
- Force Converter: convert newtons, pounds-force and more.
- All Converter Tools.
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