Weight Converter

The Weight Converter changes a mass value between units such as grams, kilograms, and metric tonnes on the metric side and ounces, pounds, and stones on the imperial and US customary side. You enter an amount in one unit, pick the unit you want, and the tool returns the equivalent immediately, which saves you from remembering conversion factors or doing error-prone arithmetic by hand.

Conversions use precise defined relationships: one pound equals exactly 0.45359237 kilograms, one ounce is one-sixteenth of a pound (about 28.35 grams), and one stone equals 14 pounds. The tool generally converts your entry to a base unit like grams or kilograms first, then to the target unit, ensuring the same answer no matter which pair of units you select. Note that these are units of mass; while everyday usage says weight, the values represent how much matter an object contains rather than the gravitational force on it.

People use weight conversion for cooking and baking recipes written in unfamiliar units, shipping and postage where carriers price by kilograms or pounds, fitness tracking that mixes kilograms and pounds, and scientific or lab work that standardizes on grams. The stone unit in particular is common for body weight in the UK and Ireland, so converting stones to pounds or kilograms is a frequent need for international health and fitness contexts.

For best results, keep enough decimal places when converting small quantities like grams to ounces, where rounding matters. Be careful not to confuse weight with volume units such as fluid ounces, which measure capacity, not mass. If your task involves human body height alongside weight, you may also want a Height Converter, and for general distance figures a Length Converter covers those units.