Convert kilograms into stones plus leftover pounds, with total pounds, decimal stones, and an optional comparison weight.
Table of contents
How to use our Kilograms to Stones and Pounds Converter
- Enter the number from your scale, app, form, or note in Weight (kg).
- Open Advanced options if you want to change Round leftover pounds to (lb) or enter Compare with another weight (kg).
- Select Calculate to see Weight in stones and pounds first, followed by Total pounds and Decimal stones.
- Sanity-check the answer: each stone is 14 lb, so the leftover pounds should be from 0 up to less than 14 unless rounding carries it to the next stone.
Definitions
Weight (kg): The weight entered in kilograms, usually copied from a scale, app, medical note, or form.
Stone (st): A UK-style weight unit equal to 14 pounds.
Leftover pounds: The pounds left after taking out as many full stones as possible.
Total pounds: The same weight shown only in pounds, without splitting it into stones.
Decimal stones: The same weight shown as a decimal number of stones, such as 11.02 st.
Round leftover pounds to (lb): The size of the rounding step used only for the pounds part of the main stones-and-pounds answer.
Compare with another weight (kg): An optional second kg value used to show the signed change from that comparison weight.
Common mistakes and quick fixes
Mistake: Typing a pounds value into Weight (kg).
Fix: Enter kilograms only, or convert pounds to kg before using this converter.
Mistake: Adding letters like kg or kilos inside Weight (kg).
Fix: Type only the number, such as 70 or 70.5.
Mistake: Thinking Round leftover pounds to (lb) changes Total pounds.
Fix: Use Round leftover pounds to (lb) only to choose how the pounds part is displayed; Total pounds is calculated from the kg value.
Mistake: Reading Decimal stones as the same format as Weight in stones and pounds.
Fix: Use Weight in stones and pounds for the spoken-style answer, and Decimal stones only when a form or table uses a decimal.
Mistake: Treating Compare with another weight (kg) as required.
Fix: Leave Compare with another weight (kg) blank if you only want the conversion.
Mistake: Seeing Rounding note mention a carry into the next stone and assuming the conversion failed.
Fix: When rounded leftover pounds reaches 14 lb, the converter correctly adds 1 stone and shows 0 lb leftover.
Limitations & Key Assumptions / Boundary Conditions
- This converter changes units only. It does not tell whether a weight is healthy or medically important.
- The main Weight in stones and pounds result rounds only the leftover pounds part based on Round leftover pounds to (lb).
- Total pounds and Decimal stones are supporting values for checking, so they may show more precision than the main spoken-style answer.
- Compare with another weight (kg) uses current Weight (kg) minus the comparison weight. A negative change means the current weight is lower.
- The result depends on the kg value you enter. Clothing, scale calibration, time of day, and record-keeping can change real measured weight.
- Very large numbers are converted mathematically, but real scales, travel forms, and medical systems may have their own allowed ranges and rounding rules.
Methodology
Core conversion
The entered Weight (kg) is cleaned by removing commas and spaces. It must be a number that is 0 or greater.
The calculator first changes kilograms to pounds using the standard factor 0.45359237 kg per pound.
total_lb = kg / 0.45359237
It then splits total pounds into whole stones and leftover pounds using 14 lb per stone [2].
whole_stones = floor(total_lb / 14)
leftover_lb_exact = total_lb - whole_stones * 14
Rounding and comparison
The selected Round leftover pounds to (lb) value is used only for the displayed leftover pounds in the main answer.
leftover_lb_rounded = round(leftover_lb_exact / rounding_step) * rounding_step
If the rounded leftover pounds is 14 lb or more, the converter adds 1 to whole stones and shows 0 lb leftover. This prevents an answer such as 10 st 14 lb.
Decimal stones is calculated from the unrounded total pounds.
decimal_stones = total_lb / 14
If Compare with another weight (kg) is filled in, the change is signed and is not clamped to zero.
change_kg = kg - compare_kg
change_lb = change_kg / 0.45359237
Mini example
For 70 kg, total pounds is 154.3236 lb. Eleven full stones use 154 lb, leaving 0.3236 lb. With Round leftover pounds to (lb) set to 0.1 lb, the main answer is 11 st 0.3 lb. Decimal stones is 11.0231 st.