Weight Converter

By Suraj GiriUpdated 24 September 2026

This page converts a mass from one unit into another. Every value passes through the kilogram, the SI unit mass is held in, and mass stays mass: a unit only converts inside its own dimension.

How do you convert a weight between kilograms, pounds and stone?

Pick the unit you have, pick the unit you want, and type the value. The page multiplies by the factor between the two and prints the arithmetic under the result, so the answer and the working are the same object.

1. Choose the unit your value is in. This page opens on the kilogram.
2. Choose the unit you want it in. This page opens on the pound.
3. Type the value, or the value with its units, such as 70 kg to lb. The result and the factor behind it appear together.
4. Read the working. It converts into the kilogram first and out again, which is the same two lines you would write by hand.

Kilograms, pounds and stone measure mass only, so for a value in litres, metres or another quantity's units, choose its page on the unit converter.

Mass Conversion Table

One row per unit this page offers, each measured against the kilogram. The last column says whether the factor is a definition or a reading of one.

Worked Examples

The questions the bank ranked highest for this page, answered with the working.

Common Mass Conversions

Each US customary or imperial unit on this page against the metric unit nearest it in size, both ways. Exact values print in full; the rest are rounded to 10 significant figures. Select one to load it into the converter.

• 1 oz = 28.34952313 g
• 1 g = 0.03527396195 oz
• 1 lb = 0.45359237 kg
• 1 kg = 2.204622622 lb
• 1 st = 6.35029318 kg
• 1 kg = 0.1574730444 st
• 1 short ton = 0.90718474 t
• 1 t = 1.102311311 short ton
• 1 long ton = 1.016046909 t
• 1 t = 0.9842065276 long ton

Where These Factors Come From

Every factor above is read from the knowledge base rather than typed for the page, and every result is worked from those factors. These are the statements it holds for mass.

• One avoirdupois pound is exactly 0.45359237 kg. One ounce is a sixteenth of a pound, 0.028349523125 kg, and one stone is fourteen pounds, 6.35029318 kg.
• A kilogram measures mass; a newton measures weight, the force gravity exerts on that mass. This page scales mass, so its result does not change with location.
• An exact factor is a definition rather than a measurement. 1 in = 25.4 mm and 1 lb = 0.45359237 kg were fixed by the 1959 international yard and pound agreement, so they never gain another digit.
• standard acceleration of free fall, value 9.80665
• How this page reports a result result as a mass in the target unit; no local gravity is applied

SI prefixes on this page

Is It Mass or Weight?

Everything on this page is a mass. Weight is a force and depends on where the measurement is taken; a kilogram of flour holds the same mass anywhere, and no local gravity is applied to any result here.

• Turning kilograms into newtons is not a unit conversion. It multiplies by the local pull of gravity, which this page does not apply.
• The short ton, the long ton and the tonne are three different units, so a figure given in tons needs to say which one it means.
• A stone is counted in pounds, not in kilograms, so a weight in stone converts through the pound.

The rule behind this factor is the same for every unit - what makes a factor exact.

Frequently Asked Questions

Related Conversions

• If you are measuring volume rather than mass, convert a volume between cups and millilitres instead.
• Pressure sits in the same measurement group as mass - read a pressure in another unit.
• If you are measuring length rather than mass, convert a height between centimetres, feet and inches instead.
• If you are measuring temperature rather than mass, convert an oven temperature between Celsius and Fahrenheit instead.
• Torque sits in the same measurement group as mass - torque in newton-metres, pound-feet and kilogram-force metres.
• If you are measuring parts-per ratio rather than mass, convert a concentration between ppm and percent instead.

The rest of the family sits on pick another quantity to convert.