How to Use This Weight Converter
Our weight converter provides instant conversions between any weight or mass units. Enter the value you want to convert, select your starting unit from the dropdown menu, then choose your target unit. Results appear immediately with customizable precision—from whole numbers to many decimal places for scientific applications.
The converter supports 40+ units across multiple categories: metric (kilograms, grams, milligrams, metric tons), imperial (pounds, ounces, tons), and specialized units (stones, grains, carats for gems, troy ounces for precious metals). Use the quick conversion buttons for common conversions like kilograms to pounds or grams to ounces.
Common Weight Conversions
These are the most frequently needed weight conversions in everyday life:
- Pounds to Kilograms: Multiply by 0.453592 (1 lb = 0.454 kg). A 150-pound person weighs 68.04 kg.
- Kilograms to Pounds: Multiply by 2.20462 (1 kg = 2.205 lbs). A 70 kg person weighs 154.3 pounds.
- Ounces to Grams: Multiply by 28.3495 (1 oz = 28.35 g). An 8 oz steak weighs 226.8 grams.
- Grams to Ounces: Divide by 28.3495 or multiply by 0.03527 (100 g ≈ 3.53 oz).
- Stones to Pounds: Multiply by 14 (1 stone = 14 lbs). 10 stones = 140 pounds.
- Pounds to Ounces: Multiply by 16 (1 lb = 16 oz). 2.5 pounds = 40 ounces.
Cooking Weight Conversions
Accurate weight measurements are crucial for successful cooking, especially in baking where precision affects texture and rise:
Why Weight Beats Volume: A cup of flour can weigh 120-150 grams depending on how it's scooped and settled. Professional bakers always weigh ingredients for consistency. Digital scales eliminate guesswork and improve results significantly.
Common Ingredient Weights: 1 cup all-purpose flour = 120-130g, 1 cup granulated sugar = 200g, 1 cup brown sugar (packed) = 220g, 1 cup butter = 227g (2 sticks), 1 large egg = 50g, 1 cup milk = 240g. These vary by ingredient—always weigh for best results.
International Recipes: American recipes use cups and ounces, while European recipes use grams and milliliters. Converting accurately prevents recipe failures. When converting from volume to weight, research the specific ingredient's density—don't assume all powders or liquids have the same conversion factor.
Body Weight Tracking
Understanding weight measurements helps with fitness and health goals:
Choosing Your Unit: Most of the world uses kilograms for body weight, while the US primarily uses pounds. Stones are common in the UK and Ireland. Choose whichever feels most intuitive, but understand conversions for medical visits or international discussions.
Weight Fluctuations: Daily weight can vary 2-5 pounds (1-2.3 kg) due to water retention, food in digestive system, and hormones—not fat gain/loss. Weigh yourself at the same time daily (morning after bathroom, before eating) for consistent tracking. Weekly or monthly averages provide better progress indicators than daily weigh-ins.
Healthy Weight Loss Rate: Aim for 0.5-2 pounds (0.23-0.9 kg) per week for sustainable fat loss. Faster loss often includes water and muscle, not just fat. One pound of body fat equals approximately 3,500 calories, so a 500-calorie daily deficit yields about 1 pound of loss per week.
Shipping Weight Calculations
Accurate weight measurements are essential for shipping costs and compliance:
Dimensional Weight: Carriers often charge based on dimensional weight (size) vs actual weight, whichever is greater. Calculate dimensional weight by multiplying length × width × height (in inches), then dividing by 139 for domestic or 166 for international. If this exceeds actual weight, you're charged for dimensional weight.
International Shipping: Most international carriers use metric (kilograms), while domestic US carriers use pounds. Always verify which system your carrier uses to avoid surprises. Rounding practices vary—some carriers round up any fraction, others use standard rounding to nearest pound or kilogram.
Accuracy Matters: Under-reporting weight can result in surcharges when carriers verify weight at processing facilities. Over-reporting wastes money. Use a calibrated scale and include all packaging materials in your weight measurement. Carriers typically allow 1-2% variance before applying surcharges.
Troy Weight vs Avoirdupois Weight
Two different weight systems coexist for historical reasons:
Avoirdupois System: The standard system for nearly everything—groceries, body weight, shipping. Uses 16-ounce pounds and 2,000-pound tons. An avoirdupois ounce = 28.3495 grams. This system developed from medieval English merchants.
Troy System: Used exclusively for precious metals (gold, silver, platinum) and gemstones. A troy ounce = 31.1035 grams (about 10% heavier than avoirdupois ounces). Confusingly, a troy pound has only 12 troy ounces (vs 16 in avoirdupois pounds), making a troy pound lighter than an avoirdupois pound.
Why It Matters: When buying gold, "one ounce" means a troy ounce, not a regular ounce. At $2,000 per troy ounce, that 10% difference represents $200. Always clarify which ounce system applies when dealing with precious metals to avoid costly misunderstandings.
Frequently Asked Questions
What's the difference between weight and mass?
Mass is the amount of matter in an object and doesn't change based on location—measured in kilograms or grams. Weight is the force of gravity on that mass and varies by location—measured in newtons (or pounds/ounces commonly). On Earth, we use the terms interchangeably, but your weight on the Moon would be 1/6th of Earth's, while your mass remains constant.
How do I convert recipe measurements?
For baking precision, use weight over volume when possible. Common conversions: 1 cup flour ≈ 120-130g, 1 cup sugar ≈ 200g, 1 cup butter ≈ 227g (1/2 pound). Note that volume-to-weight conversions vary by ingredient density—1 cup of feathers weighs less than 1 cup of lead. Digital kitchen scales provide accuracy.
How accurate are kitchen scales?
Digital kitchen scales typically accurate to ±1-2 grams, sufficient for most cooking. Higher-end scales offer ±0.1g precision for baking or coffee brewing. Mechanical scales are less accurate (±5-10g). For best results, calibrate your scale periodically, use on a flat surface, and tare (zero) before each measurement.
What's a stone in pounds?
One stone equals 14 pounds or 6.35 kilograms. This unit is commonly used in the UK and Ireland for body weight. A person weighing 11 stone weighs 154 pounds or about 70 kg. The stone measurement dates back to ancient times when stones were standardized weights for trade.
How do I convert baby weight to metric?
Babies born in the US are typically measured in pounds and ounces. To convert: multiply pounds by 0.453592 to get kg, then multiply ounces by 0.0283495 and add. For example: 7 lbs 8 oz = (7 × 0.453592) + (8 × 0.0283495) = 3.175 + 0.227 = 3.402 kg. Many hospitals provide both measurements.
What's a troy ounce vs regular ounce?
Troy ounces measure precious metals (gold, silver) and equal 31.1035 grams. Regular (avoirdupois) ounces measure everything else and equal 28.3495 grams. There are 12 troy ounces in a troy pound but 16 regular ounces in a pound. This difference matters significantly in precious metal pricing—always verify which ounce system is being used.