# Stone to kilograms converter

> Convert stone to kilograms (stone to kg) with the exact factor, a conversion chart and worked steps.

Interactive version: https://www.calcopenly.com/conversion/stones-to-kg
Subject: Unit converters

A body-weight record in stone sometimes includes an additional number of pounds. Decimal stone is a different notation: 11.5 stone means eleven and a half stone. Convert mixed stone-and-pound records to a single stone value before using this field.

One stone is exactly 6.35029318 kilograms, so 11 st is 69.853225 kg. To convert stone to kg, multiply by 6.35029318; to convert back, multiply by 0.1574730444.

The stone is 14 pounds, exactly 6.35029318 kg. Because both units are defined exactly, the factor above is exact and the results here carry no conversion error.

## Inputs

- **Stone (st)**

## Results

- Kilograms (kg) — main result
- Conversion
- 1 kg in stone (st)

## Formula

$$
\text{kilograms} = \text{stone} \times 6.35029318
$$

## Worked examples

### 11 st to kg

- Stone (st): 11 st
- **Kilograms: 69.85322498 kg**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 9 st to kg

- Stone (st): 9 st
- **Kilograms: 57.15263862 kg**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 15 st to kg

- Stone (st): 15 st
- **Kilograms: 95.2543977 kg**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

## Questions

### When would I convert stone to kg?

A body-weight record in stone sometimes includes an additional number of pounds. Decimal stone is a different notation: 11.5 stone means eleven and a half stone. Convert mixed stone-and-pound records to a single stone value before using this field.

### How many kilograms are in a stone?

One stone is exactly 6.35029318 kilograms. The stone is 14 pounds, exactly 6.35029318 kg.

### How do you convert stone to kg?

Multiply the number of stone by 6.35029318. For example, 11 st × 6.35029318 = 69.853225 kg. To go the other way, divide by 6.35029318.

### How can I estimate stone to kg without a calculator?

Multiply by 6.4. That is 0.8% high of the exact factor 6.35029318, so 11 st comes out as 70.4 kg instead of 69.8532.

### How accurate is the stone to kilograms converter?

Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 3 worked examples whose answers come from independent sources; for example, “11 st to kg” is checked against Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions).

### Where does the method come from?

NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B; NIST Handbook 44, Appendix C: General tables of units of measurement; BIPM, The International System of Units (SI Brochure), 9th edition.

## Sources

- [NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44, Appendix C: General tables of units of measurement](https://www.nist.gov/pml/weights-and-measures/publications/nist-handbooks/handbook-44)
- [BIPM, The International System of Units (SI Brochure), 9th edition](https://www.bipm.org/en/publications/si-brochure)