Introduction
This pounds to kilograms calculator changes any weight in pounds (lb) into kilograms (kg). Type a number, and the answer shows up right away. You can also go the other way and turn kilograms into pounds. Just click the Swap button, or use our dedicated kg to lbs calculator.
The math is simple: 1 pound = 0.45359237 kilograms. So to get kilograms, you multiply the pounds by 0.45359237. To go back, you multiply the kilograms by 2.20462262. The tool does this for you, and it shows each step so you can see how the answer was found.
You can also enter weight as pounds plus ounces, like 8 lb 6 oz. Pick how many decimal places you want to see, from 2 up to 8. The tool also shows the same weight in grams, tonnes, ounces, and stones. For smaller kitchen amounts, the ounces to grams calculator and the grams to ounces calculator handle those swaps directly.
People use this for many things: baggage limits at the airport, body weight, gym plates, food recipes, shipping boxes, and school homework. Quick buttons and a reference table let you load common weights with one tap, and a chart compares your weight to everyday objects.
How to use our Pounds to Kilograms Calculator
Type a weight in pounds and the tool shows the same weight in kilograms, plus the math steps, a chart, and other units like grams, ounces, and stones.
Pounds (lb): Type your weight in pounds here. The kilogram answer updates as you type.
Switch to lb + oz: Click this button if your weight has ounces too. Then fill the Pounds box and the Ounces box (16 oz = 1 lb).
Kilograms (kg): Type here instead to go the other way and change kilograms to pounds.
Swap: Click this to flip the direction between lb → kg and kg → lb.
Decimal places shown: Pick 2, 4, 6, or 8 to set how many digits show after the dot. This only changes the display, not the math. If you need to round to a set number of significant digits instead, try the sig fig calculator or the rounding calculator.
Quick Select (pounds): Tap a common weight, like 50 lb or 150 lb, to load it fast.
Show comparison in: Pick a unit for the bar chart to compare your weight with everyday items.
Calculate, Clear, and Copy: Press Calculate to run the conversion, Clear to empty the fields, and Copy to save the answer to your clipboard.
Pounds to Kilograms (lbs to kg)
A pound and a kilogram both measure weight, but they come from two different systems. The pound (lb) is part of the imperial system, used mostly in the United States. The kilogram (kg) is part of the metric system, used by most of the world and by scientists everywhere. Length works the same way, which is why tools like the feet to meters calculator and the cm to inches calculator are so handy.
The Formula
To change pounds into kilograms, multiply by 0.45359237:
kilograms = pounds × 0.45359237
To go the other way, multiply kilograms by 2.20462262:
pounds = kilograms × 2.20462262
This number is not a guess. In 1959, several countries signed an agreement that set one pound to exactly 0.45359237 kilograms. That value is still the official one today.
A Quick Trick in Your Head
You don't always need a calculator. Just cut the pounds in half, then take off about 10%. So 150 lbs → 75 → about 68 kg. The real answer is 68.04 kg, so this trick gets you very close. Another easy way is to divide by 2.2. If you want to know how far off a shortcut like this is, the percent error calculator will tell you.
Pounds and Ounces
Weights are often written as pounds plus ounces, like a baby who weighs 7 lb 8 oz. There are 16 ounces in one pound. To convert, first turn the ounces into a decimal by dividing by 16, then multiply the total by 0.45359237. So 7 lb 8 oz = 7.5 lbs = 3.4019 kg. Parents tracking growth can plug that kilogram figure into the baby percentile calculator, and puppy owners can do the same with the puppy weight calculator.
Other Weight Units
- 1 stone = 14 pounds = 6.35029 kg (used in the UK for body weight)
- 1 ounce = 28.3495 grams
- 1 kilogram = 1,000 grams
- 1 metric tonne = 1,000 kg = 2,204.62 pounds
Where You Will Use This
Converting pounds to kilograms comes up more than you might think. Airlines list bag limits in kilograms overseas but pounds in the US. Gym weights, recipes, shipping labels, and medicine doses all switch between the two. Doctors often record body weight in kilograms because drug amounts are figured per kilogram.
Here are a few places the swap shows up most often:
- Health and fitness: The BMI calculator, ideal body weight calculator, lean body weight calculator, and adjusted body weight calculator all work in kilograms. So does the BSA calculator used for dosing.
- Weight goals: Track progress with the weight loss calculator, weight gain calculator, or calorie deficit calculator. Daily needs come from the TDEE calculator and BMR calculator.
- Lifting: Gym plates are sold in both units, so pair this tool with the 1RM calculator, bench press calculator, or DOTS calculator.
- Shipping: Carriers bill in kilograms abroad. See the volumetric weight calculator, shipping calculator, freight density calculator, and CBM calculator.
- Materials: Metal and building supplies are quoted either way — try the metal weight calculator, steel weight calculator, or concrete weight calculator.
- Pets: Feeding charts often use kilograms, which matters for the dog food calculator and the chocolate toxicity calculator.
Weight vs. Mass
In everyday talk, people say "weight" for both. But mass is how much stuff is in an object, and weight is the pull of gravity on it. Pounds and kilograms are used here as mass units, so the conversion works the same on Earth or anywhere else. If you need the force side of the story, the mass calculator, force calculator, gravitational force calculator, and density calculator cover it. Temperature units flip between systems too — see the Celsius to Fahrenheit calculator.