Stone to pounds (st to lbs) converter

What are stone, pounds and kilograms?

These three units measure mass, but they come from different traditions. Stone and pounds belong to the imperial system still used for body weight in the United Kingdom and Ireland, while the kilogram is the metric standard used almost everywhere else. A reliable converter bridges all three so a weight quoted in one system makes sense in the others.

Stone (st)

A stone is a unit of mass equal to exactly 14 pounds, or about 6.35 kilograms. It survives today mainly as the everyday way people in Britain and Ireland describe their body weight — “eleven stone four”, for example, means 11 stone plus 4 pounds. The plural of the unit is unusual: people say “eleven stone”, not “eleven stones”.

Pounds (lbs)

A pound is the base unit of weight in the imperial and US customary systems. One pound equals exactly 0.45359237 kilograms by international agreement, and 14 pounds make one stone. In the United States, body weight is quoted directly in pounds rather than stone.

Kilograms (kg)

The kilogram is the base unit of mass in the metric system and the international standard for science, medicine, and most of the world’s everyday use. One kilogram equals about 2.205 pounds, so a single stone is just over 6.35 kilograms.

How does the calculator work?

The tool links three fields — stone, pounds, and kilograms. Enter a value in any one of them and the other two recalculate instantly. Internally the converter routes everything through the exact factors below, so a number you type as stone is first scaled to pounds and kilograms, and a number you type as kilograms is scaled back the other way.

Conversion formulas

$$\text{Pounds} = \text{Stone} \times 14$$ $$\text{Kilograms} = \text{Stone} \times 6.35029318$$ $$\text{Kilograms} = \text{Pounds} \times 0.45359237$$ $$\text{Stone} = \frac{\text{Pounds}}{14}$$

Conversion table

Worked examples

Example 1: Convert 1 stone to pounds and kilograms

$$\text{Pounds} = 1 \times 14 = 14$$ $$\text{Kilograms} = 1 \times 6.35029318 = 6.35029$$

So 1 stone equals 14 lb, which is about 6.35029 kg.

Example 2: Convert 10 stone to pounds and kilograms

$$\text{Pounds} = 10 \times 14 = 140$$ $$\text{Kilograms} = 10 \times 6.35029318 = 63.5029$$

A weight of 10 stone is therefore 140 lb, or roughly 63.5029 kg.

Example 3: Convert 70 pounds to stone

$$\text{Stone} = \frac{70}{14} = 5$$

Thus 70 lb is exactly 5 stone.

Practical notes

• Body weight in stone is almost always combined with leftover pounds, as in “11 st 4 lb”. To convert that to a single number, multiply the stone by 14 and add the spare pounds before converting further.
• For a quick mental estimate, treat one stone as roughly 6.35 kg, or just over 6 and a third kilograms.
• Need only the metric-imperial step? Use our kilograms to pounds converter or the pounds to kilograms converter.

Frequently asked questions

How many pounds are in a stone?

There are exactly 14 pounds in one stone. To convert stone to pounds, multiply by 14.

How many kilograms are in a stone?

One stone equals about 6.35029 kilograms. The exact factor is 6.35029318 kg per stone.

How do I convert pounds to stone?

Divide the number of pounds by 14. For example, 70 lb divided by 14 gives exactly 5 stone.

Why is stone still used for body weight?

Stone remains the customary way to state body weight in the United Kingdom and Ireland, largely because of long-standing habit. Most other countries use either kilograms or pounds directly.

Is the conversion between pounds and kilograms exact?

Yes. By international agreement one pound is defined as exactly 0.45359237 kilograms, so the pound-to-kilogram conversion involves no approximation.