Total Kilograms
0
Equivalent weight
Accurate weight conversion tool for stones and kilograms
Convert stones to kilograms instantly with precise calculations. Includes stones & pounds to kg mode, bidirectional conversion, and complete weight breakdowns for 2026.
Professional weight conversion for health, fitness, travel, and everyday use
Convert stones to kilograms using the exact factor of 6.35029318 kg per stone. Our stones to kilograms converter delivers full precision for body weight, luggage limits, and any other weight measurement — from a fraction of a stone to hundreds of stones, with up to 6 decimal places of accuracy.
Switch freely between stones to kg, kg to stones, and the very popular stones & pounds to kg mode. The stones and pounds mode is essential for UK and Irish users who express body weight as, for example, "11 stone 4 pounds" — enter both values and get an instant, accurate kilogram result.
Essential for tracking body weight, comparing NHS and international health guidelines, airline baggage allowances, fitness and gym records, medical consultations, and sports performance tracking. Whether you're in the UK, Ireland, or comparing weights internationally, this tool gives reliable results every time.
Select a conversion mode and enter your value below
The stone (st) is a unit of weight in the imperial system, primarily used in the United Kingdom and Ireland to express body weight. One stone is defined as exactly 14 pounds. The kilogram (kg) is the SI base unit of mass, used universally in science and in most countries worldwide. Converting between stones and kilograms is a daily need for millions of people across the UK, Ireland, and internationally.
The exact conversion factor is 1 stone = 6.35029318 kilograms, derived from the defined pound-to-kilogram relationship (1 pound = 0.45359237 kg) multiplied by 14. This converter is widely used for body weight tracking, medical records, gym and fitness applications, and any context requiring conversion between British imperial and metric weight units.
1 stone = 14 lbs × 0.45359237 kg/lb = 6.35029318 kg
Use this quick-reference table to find common stones to kilograms conversions instantly. All values are calculated using the exact factor of 1 stone = 6.35029318 kg.
| Stones (st) | Kilograms (kg) | Pounds (lbs) | St & lbs (approx) | Common Reference |
|---|---|---|---|---|
| 1 st | 6.350 kg | 14 lbs | 1 st 0 lbs | Small child |
| 4 st | 25.402 kg | 56 lbs | 4 st 0 lbs | Young child |
| 6 st | 38.102 kg | 84 lbs | 6 st 0 lbs | Older child |
| 8 st | 50.802 kg | 112 lbs | 8 st 0 lbs | Lightweight adult |
| 9 st | 57.153 kg | 126 lbs | 9 st 0 lbs | Petite adult |
| 10 st | 63.503 kg | 140 lbs | 10 st 0 lbs | Average adult (female) |
| 11 st | 69.853 kg | 154 lbs | 11 st 0 lbs | Average adult |
| 12 st | 76.204 kg | 168 lbs | 12 st 0 lbs | Average adult (male) |
| 13 st | 82.554 kg | 182 lbs | 13 st 0 lbs | Larger adult |
| 14 st | 88.904 kg | 196 lbs | 14 st 0 lbs | Heavy adult |
| 16 st | 101.605 kg | 224 lbs | 16 st 0 lbs | Very heavy adult |
| 20 st | 127.006 kg | 280 lbs | 20 st 0 lbs | Bariatric reference |
Converting stones to kilograms requires a single multiplication step. For the very common case of a weight expressed in stones and pounds combined, a two-step calculation is needed first. Both methods are shown below.
Never multiply stones by 6.35 and then add pounds directly in kilograms. Pounds must first be converted to kilograms (multiply by 0.45359237) before adding to the stones value. For example, 10 st 7 lbs ≠ (10 × 6.35) + 7 = 70.5 kg. The correct answer is (10 × 14 + 7) × 0.45359237 = 66.678 kg. Always convert pounds separately before adding.
The stones to kilograms converter is one of the most commonly used personal weight conversion tools in the UK and Ireland, where body weight is still traditionally expressed in stones despite the widespread adoption of metric units in other contexts.
UK GP surgeries, hospitals, and NHS services frequently record patient weight in kilograms for clinical records, drug dosage calculations, and BMI assessments — while patients report their weight in stones. Converting accurately between the two is essential for safe, consistent healthcare delivery.
Fitness apps, gym membership forms, and personal trainers in the UK use kilograms for training programmes, while many clients only know their weight in stones. Accurate st to kg conversion ensures correct exercise prescriptions, calorie targets, and performance tracking for all users.
International airlines list baggage weight limits exclusively in kilograms. UK and Irish travellers accustomed to thinking in stones need a fast, reliable stones to kilograms converter to avoid excess baggage fees and ensure their luggage meets weight restrictions before reaching the airport.
Body Mass Index (BMI) is calculated using kilograms and metres. Since many UK residents know their height in feet/inches and weight in stones, converting stones to kilograms is a necessary first step before any BMI calculation can be performed to assess healthy weight ranges.
Combat sports such as boxing, wrestling, and MMA use weight classes defined in both pounds and kilograms internationally. British fighters and coaches routinely convert between stones and kilograms when tracking weight cuts, comparing fighters across international promotions, and meeting regulatory requirements.
UK school curricula include unit conversion between stones/pounds and kilograms as part of the Key Stage 3 and 4 mathematics syllabus. Students need accurate, fast conversion for exam questions, real-world problem solving, and understanding the relationship between imperial and metric weight systems.
The conversion factor of 6.35029318 kg per stone comes from two defined relationships in the imperial-metric system. First, one stone is defined as exactly 14 avoirdupois pounds. Second, one pound is defined as exactly 0.45359237 kilograms (this is an exact international standard, not an approximation). Multiplying these together gives: 14 × 0.45359237 = 6.35029318 kg.
Because both the pound definition (14 per stone) and the kg value (0.45359237 kg/lb) are exact international standards, the stones-to-kilograms conversion factor of 6.35029318 is also an exact value — not a rounded approximation. This is the same precision used in medical, scientific, and official government weight conversion contexts globally.
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