Unit Conversion
Instantly convert weight and mass between kilograms, pounds, grams, ounces, and stones.
Common Weight Conversion Formulas
Weight conversion translates values between the metric system (grams, kilograms) and the imperial system (pounds, ounces, stones).
- 1 Kilogram (kg) = 2.20462 Pounds (lbs)
- 1 Pound (lbs) = 453.592 Grams (g)
- 1 Stone (st) = 14 Pounds (lbs)
- 1 Ounce (oz) = 28.3495 Grams (g)
Choosing precision
Report only as many decimals as the scale, package, or specification supports. A conversion may produce many digits, but those digits do not make an imprecise measurement more accurate. Keep the original unit visible, check whether the unit is mass or volume, and document any required upward rounding for postage or compliance. For repeated work, use the same scale and procedure each time.
When to Use a Weight Converter
A weight converter is useful when a recipe, fitness plan, product label, or shipping quote uses a different unit from the one on your scale. Enter a value once to compare kilograms, pounds, grams, ounces, stones, and milligrams at the same time.
Weight Conversion FAQs
How many pounds are in a kilogram?
One kilogram equals approximately 2.20462 pounds. For everyday estimates, 1 kg is often rounded to 2.2 lb.
How many grams are in an ounce?
One avoirdupois ounce equals approximately 28.3495 grams. This is the standard ounce used for most food, household, and shipping measurements.
How to Convert Weight Units
Select the starting unit, enter a value, and choose the unit you need. Common relationships are 1 kilogram = 1,000 grams, 1 pound = 16 ounces, and 1 kilogram ≈ 2.20462 pounds. The calculator keeps additional precision before displaying a rounded result. Use the unit required by the recipe, carrier, form, or specification.
Worked examples
For 2.5 kg, multiply by 1,000 to get 2,500 g. For 5 lb, divide by 2.20462 to get about 2.27 kg. A fluid ounce measures volume, not mass, so it cannot be converted to a mass ounce without knowing the substance density. Keep the original value beside the converted result in a shipping or laboratory record.
Accuracy, mistakes, and limits
Tare the container, use a stable surface, and repeat surprising scale readings. Do not type pounds into a kilograms field or round each item before adding a shipment. For medication, laboratory work, regulated trade, or nutrition advice, follow the required specification and use calibrated equipment. This tool performs unit arithmetic; it does not verify the physical measurement.
Related guidance
Read the weight conversion guide for more examples and safe rounding. If the weight is being used with height for a broad health screening estimate, see the BMI calculator and discuss meaningful interpretation with a professional.
Weight Conversion Formula
Choose the source and destination units before entering a value. One avoirdupois pound equals exactly 453.59237 grams, one kilogram equals 1,000 grams, and one pound equals 16 ounces. To convert 2.5 kg to pounds, multiply by 2.20462262: 2.5 × 2.20462262 = 5.5116 lb. To convert 12 oz to grams, multiply by 28.349523125.
Precision and real-world checks
Keep extra decimals during the calculation and round at the end according to the task. A recipe scale may use whole grams; a shipping label may use the carrier’s rounding rule. Tare containers, check that a scale is level, and remember that liquid volume is not mass unless density is known. “Ton” can mean different standards, so confirm the definition.
Mistakes and FAQs
Six pounds eight ounces is 6.5 pounds, not 6.08 pounds. Can milliliters become grams? Only with a substance density. Why does a package cost more than its scale weight? Dimensional weight may apply. Check the weight conversion guide for examples, and use the calorie calculator when weight is part of an energy estimate.
Unit Sanity Checks
Use an approximate relationship before trusting a precise answer: 1 kg is a little over 2.2 lb, 1 lb is about 454 g, and 1 oz is about 28 g. If a conversion is ten or one hundred times away from this estimate, check the unit selector and decimal separator. Keep the source value in your notes for traceability.
When precision matters
Use the scale and unit specified by a recipe, carrier, laboratory, or professional. Never use a household conversion as a medication dose. For shipping, measure the package and ask whether dimensional weight or a minimum billable weight applies.
Choosing a Rounding Rule
Use grams for a recipe, kilograms for a person or shipment, and the carrier’s required unit for a label. Do not round a conversion to a whole number when the rounded value could cross a billing, safety, or recipe threshold. Show both the precise result and the chosen display value when reviewing work.
Reverse check
Convert the answer back to the source unit and compare it with the starting value. A small difference from final rounding is expected; a factor-of-ten difference indicates a unit error.
Convert weight and mass consistently
Use this converter when a recipe, shipping label, health record, or product specification uses a different unit. Common relationships are 1 kilogram = 1,000 grams, 1 pound = 16 ounces, and 1 kilogram is approximately 2.20462 pounds. To convert pounds to kilograms, divide by 2.20462; 150 lb is about 68.04 kg.
Formula examples
Multiply when moving from a larger unit to a smaller unit: 2.5 kg times 1,000 equals 2,500 g. For pounds to ounces, multiply by 16, so 3.25 lb equals 52 oz. For ounces to pounds, divide by 16, so 20 oz equals 1.25 lb. Keep the unrounded value while converting several times, then round at the end.
How to choose a result
- Confirm whether the source means mass, everyday weight, or a shipping system's billable weight.
- Select the source and destination units carefully.
- Compare the converted number with a quick order-of-magnitude estimate.
- Round to the precision needed: a recipe may need grams, while a suitcase estimate may need pounds.
Important assumptions and mistakes
This page uses the international avoirdupois pound and ounce, not troy units used for precious metals. It also treats kilograms as mass; local gravitational differences are irrelevant for normal household and commercial conversions. Do not confuse fluid ounces, which measure volume, with ounces of mass. Why can two websites differ slightly? One may round the conversion factor earlier. Is 1 kg exactly 2.2 lb? It is approximately 2.2 lb, while 2.20462 gives better precision. For health context, pair a consistent unit with the BMI calculator.
Which units can I convert?
The converter supports the units listed in its controls, allowing you to translate a measurement into another supported mass unit.
Why can rounded values differ?
Conversion factors can produce repeating decimals, so displayed values may be rounded for readability.
Is weight the same as mass?
In everyday use the terms are often mixed, but physics distinguishes mass from weight.
Should I use the result for regulated measurements?
For regulated, laboratory, or commercial measurements, verify the required standard and precision.
