Convert Kilograms to Stones - Weight Converter
This converter converts a single mass value from kilograms to stones using the internationally accepted relation between the kilogram and the avoirdupois pound. It is intended for everyday use, clinical record-keeping, and quick reference when a simple, reliable conversion is required.
The conversion factor used by this tool is derived from the exact definition of the international avoirdupois pound and the kilogram as defined by international metrology authorities. Results are provided as a decimal number of stones; where desired you can convert the fractional stone to pounds or round to the precision you need.
Interactive Converter
Convert between kilogram and stone with precision rounding.
Quick reference table
| Kilogram | Stone |
|---|---|
| 1 kg | 0.1575 st |
| 5 kg | 0.7874 st |
| 10 kg | 1.5747 st |
| 25 kg | 3.9368 st |
| 50 kg | 7.8737 st |
| 100 kg | 15.7473 st |
Methodology
The tool applies the fixed mathematical relationship between kilograms and the avoirdupois system: 1 avoirdupois pound is defined as exactly 0.45359237 kilograms, and 1 stone equals 14 avoirdupois pounds. Combining those exact definitions gives 1 stone = 6.35029318 kilograms.
Because these base definitions are international standards used by national measurement institutes, the conversion itself is exact in mathematical terms. Practical accuracy depends on the precision of the input measurement (scale resolution), calibration status of the scale, and rounding choices.
For regulated or clinical measurements, follow local standards for measurement uncertainty, calibration intervals, and recordkeeping. Relevant authoritative sources include national metrology guidance, ISO standards on quantities and units, and occupational safety recommendations for manual handling limits.
Worked examples
Convert 70 kg to stones: 70 ÷ 6.35029318 = 11.0231 st (approximately 11 st 0.32 lb).
Convert 80 kg to stones: 80 ÷ 6.35029318 = 12.5984 st (approximately 12 st 8.37 lb).
Convert 1 kg to stones: 1 ÷ 6.35029318 = 0.15747 st.
Key takeaways
This converter applies the exact international definitions to convert kilograms to stones using stones = kilograms ÷ 6.35029318. The mathematical conversion is exact; practical accuracy depends on input measurement quality and rounding choices.
For regulated, clinical, or safety-critical uses follow the appropriate standards for measurement uncertainty, instrument calibration, and reporting. Cite original units and converted units together to preserve traceability.
Further resources
Expert Q&A
Is the conversion factor exact?
Yes. The factor 6.35029318 kg per stone is computed from exact international definitions: 1 lb = 0.45359237 kg (exact) and 1 stone = 14 lb. The mathematical ratio is therefore exact given those definitions.
Why do results differ slightly between tools?
Differences usually come from rounding or from whether a tool displays stones as a decimal versus stones plus remaining pounds. Also some historical or informal definitions may be used in non-standard tools; always use tools that reference international definitions for highest consistency.
How many decimal places should I use?
Choose precision based on context. For clinical records one or two decimal places in kilograms are common; for bodyweight reporting, rounding to one decimal in stones or to the nearest pound is typical. For engineering or regulatory calculations follow the precision specified by the relevant standard or procedure.
Does scale accuracy affect the conversion?
Yes. The numerical conversion is exact, but measurement uncertainty comes from the scale (resolution, calibration, repeatability). For any regulated measurement include the scale's declared uncertainty and calibration status when reporting converted values.
Can I convert stones to kilograms with this tool?
This configuration converts kilograms to stones. The reverse conversion uses the reciprocal factor: kilograms = stones × 6.35029318. Use the platform's reverse conversion or multiply by that factor when needed.
Are there safety or regulatory considerations?
When conversions are used to determine manual handling limits, clinical dosing by weight, or other regulated activities, consult applicable occupational safety guidance and clinical protocols. Always record both the original measurement units and the converted units when precision and traceability matter.
Sources & citations
- NIST Guide to the SI (units and definitions) — https://www.nist.gov/pml/weights-and-measures
- BIPM — The International System of Units (SI) — https://www.bipm.org/en/measurement-units/
- ISO — Quantities and units (ISO standards catalogue) — https://www.iso.org/ics/17.040.html
- IEEE Standards Association (standards and best practices) — https://standards.ieee.org/
- OSHA — Ergonomics and manual handling guidance — https://www.osha.gov/ergonomics