A fast and private stone to kg converter
Whether you are tracking your fitness progress, filling out a medical form, or setting up a new health app, converting between traditional and metric weight units is a common task. This stone to kg converter provides an instant, bidirectional way to translate body weight between the UK's preferred unit and the global metric standard.
The calculator updates immediately as you type. Because it runs entirely in your web browser, your data is never sent to a server or stored anywhere. You can quickly check a weight in complete privacy, without waiting for a page to reload.
How to convert stone to kg
The math behind the conversion is straightforward but difficult to do in your head. One stone is defined as exactly 14 pounds, which translates to exactly 6.35029318 kilograms.
To convert stones to kilograms manually, you multiply the stone value by 6.35. For example, a person weighing 11 stones weighs roughly 69.8 kg (11 × 6.35029).
To calculate the reverse—kg to stone—you divide the kilogram value by 6.35029. For instance, a person who weighs 75 kg weighs approximately 11.8 stones.
This stone weight converter handles the exact decimal precision for you, allowing up to 8 significant digits. It also includes a quick reference table at the bottom of the page, mapping common adult body weights from 6 stones up to 25 stones directly to their kilogram equivalents.
When to use a stone weight converter
Health and fitness tracking. Most modern digital scales allow you to switch between stones, kilograms, and pounds. However, if you are following an international fitness program, using a metric-only app, or calculating your body mass index with a BMI Calculator, you will likely need your weight in kilograms.
Medical and official forms. While people in the UK and Ireland colloquially discuss their weight in stones and pounds, medical professionals and official documents almost exclusively require metric measurements. This tool helps you quickly translate your known weight into the required format before a doctor's appointment.
Combat sports and athletics. Sports like boxing, mixed martial arts, and weightlifting use strict weight classes. Depending on the organization and the country hosting the event, these classes might be listed in kilograms or pounds. If you are used to thinking in stones, you can use this tool alongside our Kg to Lbs converter to see exactly where you stand.
International conversations. If you are speaking with someone outside the UK or Ireland, telling them you weigh "12 stone" will likely cause confusion. Converting your weight to kilograms (or pounds for North American friends) makes it universally understood.
Understanding the stone unit
The stone (abbreviated as st) has a long history in the British Imperial system. Originally, it represented the weight of a specific physical stone used as a standard measure for agricultural trade. Over centuries, the value fluctuated depending on the commodity being weighed, but it was eventually standardized at 14 avoirdupois pounds in the 19th century.
Today, the stone is almost exclusively used to measure human body weight. It is unique because it is often used in a mixed-radix system alongside pounds. Just as someone might say they are "5 foot 10" instead of 70 inches, a British person will typically say they weigh "11 stone 4" (11 stones and 4 pounds) rather than 158 pounds or 11.28 stones.
If you have a weight in stones and pounds, you can easily use this tool by converting the extra pounds to a decimal first (divide the pounds by 14). For example, 11 stone 7 pounds is exactly 11.5 stones. Enter 11.5 into the calculator, and you will instantly see the kilogram equivalent. For smaller, non-bodyweight measurements, you might also find our Grams to Ounces converter helpful.