Weight Converter
Convert between kg, lb, oz and more.
Results update as you type.
How it works
A weight converter changes a mass from one unit into another, covering metric units like milligrams, grams, kilograms and tonnes alongside imperial and customary units like ounces, pounds and stone. It reduces whatever you enter to kilograms, the base unit, and then scales out to your chosen unit, so one consistent route handles every combination across the two measurement systems. This matters because mass is quoted differently depending on where you are and what you are doing. Body weight appears in kilograms, pounds or stone depending on the country; recipes mix grams and ounces; shipping and freight juggle kilograms, pounds and tonnes. A weight converter settles those differences at once and prevents the kind of slip that turns a parcel's cost or a dose calculation into an expensive mistake. The normalise-to-kilograms method is used because every mass unit has a fixed ratio to the kilogram — one pound is exactly 0.45359237 kg, one ounce is a sixteenth of a pound — so pivoting through that base keeps every result exact. Home cooks, travellers, gym-goers tracking progress, warehouse and logistics staff, and healthcare workers all rely on a weight converter whenever a figure lands in an unfamiliar unit.
Convert to kilograms via known factors, then to the target unit
The input is multiplied by its unit's fixed ratio to the kilogram to express it in kilograms, then divided by the target unit's ratio to finish the conversion. Because every mass unit is defined as a constant number of kilograms, chaining through this single base is exact and means the converter stores just one factor per unit rather than a factor for every possible pairing.
Source:International System of Units (SI) — NIST
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter value, from and to.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Converted weight updates instantly as you type — no button to press.
Frequently asked questions
How many pounds are in a kilogram?
About 2.20462 pounds per kilogram. So 70 kg is roughly 154.32 lb, and 100 kg is about 220.46 lb. To reverse it, multiply pounds by 0.453592 to get kilograms. The factor comes from the exact definition that one pound equals 0.45359237 kilograms, so the pounds-per-kilogram figure is simply the reciprocal of that value.
How do I convert kilograms to pounds?
Multiply the kilogram figure by 2.20462, or equivalently divide by 0.453592. For example, 5 kg is about 11.02 lb. For a rough mental estimate, double the kilograms and add about ten percent. The precise route the converter uses pivots through the exact pound definition, so the displayed answer is accurate to the decimals shown rather than an approximation.
What is a stone in weight?
A stone equals 14 pounds, or about 6.35 kilograms, and is still widely used for body weight in the UK and Ireland. So 70 kg is roughly 11 stone. Stone is normally expressed with a remainder in pounds, such as 11 stone 0 pounds, rather than as a decimal. The converter reports the decimal stone value, which you can split into whole stone and pounds.
Is weight the same as mass?
Strictly, mass measures the amount of matter while weight is the force gravity exerts on it, but in everyday use the terms are interchangeable. The units here — grams, kilograms, pounds and so on — all measure mass. Because conversions between them are ratios, and gravity is effectively constant across Earth's surface, the distinction does not affect the numbers this converter produces.
How many grams are in an ounce?
One ounce is about 28.3495 grams, since an ounce is defined as one-sixteenth of a pound. So four ounces is roughly 113.4 grams, a common figure in cooking. This is the avoirdupois ounce used for everyday weight; the troy ounce used for precious metals is heavier at about 31.10 grams, so do not use this converter for gold or silver pricing.