Weight Conversions
Convert weight and mass units — kilograms, pounds, ounces, grams, and more. Free calculators with standard conversion factors for cooking, shipping, and fitness.
11 units · 6 calculators
Weight (strictly mass in physics) tells you how heavy something is. Kitchen recipes, gym programs, shipping labels, and medical dosages all use different units — grams and kilograms in metric countries, pounds and ounces in the US and UK.
Most everyday weight conversions use a simple multiplier. One pound equals exactly 0.453592 kilograms. Our tools use internationally recognized factors, including avoirdupois ounces and pounds used in commerce.
Shipping carriers enforce weight breaks in pounds or kilograms. Fitness apps and food scales may switch units in settings. Converting consistently before you compare prices or log meals avoids systematic errors that add up over a week of tracking.
Quick weight calculator
Weight Calculator
Formulas & rules
- pounds × 0.453592 = kilograms
- ounces × 28.3495 = grams
- stones × 14 = pounds (UK stone)
- kilograms ÷ 0.453592 = pounds
Popular weight conversions
- Pounds to Kilograms
- Kilograms to Pounds
- Ounces to Grams
- Grams to Ounces
- Stones to Pounds (utility)
- Carats to Grams (utility)
Real-world example
An online retailer lists a package at 2.5 kg but your postal form asks for pounds. Converting gives about 5.5 lb, helping you compare shipping rates or check weight limits for luggage.
Common mistakes
- Using fluid ounces (volume) when the label means weight ounces for ingredients.
- Forgetting that troy ounces (precious metals) differ from avoirdupois ounces.
- Treating UK and US hundredweight or ton definitions as interchangeable.
All weight conversions
Weight units explained
- Milligrams (mg)
- Also: milligrams
- Grams (g)
- Also: grams
- Kilograms (kg) · base unit
- Also: kilograms
- Metric Tons (t)
- Also: tons, metric tons
- Ounces (oz)
- Also: ounces
- Pounds (lb)
- Also: pounds, lbs
- Stones (st)
- Also: stones
- Carats (ct)
- Also: carats
- Troy Ounces (oz t)
- Also: troy ounces
- Short Tons (US) (short ton)
- Also: short tons, us tons
- Long Tons (UK) (long ton)
- Also: long tons, uk tons
Frequently asked questions
- How do I convert pounds to kilograms?
- Multiply pounds by 0.453592 to get kilograms. For example, 150 lb × 0.453592 ≈ 68.0 kg.
- Are ounces and fluid ounces the same?
- No. Weight ounces measure mass; fluid ounces measure volume. They are different units and are converted in separate categories.