Weight/Mass Converter

Weight and mass conversion calculator for grams, kilograms, pounds, ounces, stones, and tons

This Weight/Mass Converter is for the normal situation where you have a number in one unit (like kilograms on a label, pounds on a scale, or grams in a recipe) and you need the equivalent value in another unit. Instead of guessing or doing mental math, you enter a value, choose the “from” unit and the “to” unit, and the calculator returns the converted amount.

The calculator supports both metric units (micrograms, milligrams, grams, kilograms, and metric tons) and common imperial or US units (ounces, pounds, stones, US short tons, and imperial long tons). That makes it useful for cooking and nutrition labels, gym tracking, shipping and packaging, basic science homework, and international product specs where the unit system changes but the underlying quantity does not.

To use it correctly, first enter the value exactly as shown on your source, then pick the unit it is currently measured in. Next, choose the unit you want to convert to, and click Convert. The result shows the converted value with a clean two-decimal display for readability and also includes an “exact” line in higher precision. Use the two-decimal number for quick decisions and the exact line when you need accuracy for calculations or comparisons.

Assumptions and how to use this calculator

• Weight and mass are treated as equivalent for everyday conversions. This is correct for normal uses like shopping, cooking, and personal tracking.
• Conversions are based on fixed unit definitions. The calculator does not use regional “approximate” variants.
• US short ton and imperial long ton are different. Use US short ton for most US references and imperial long ton for older UK or maritime references.
• If you enter 0, the conversion result will be 0. Negative values are rejected because they do not make sense for normal weight and mass use cases.
• If you need more precise rounding rules (for example, significant figures for lab reports), use the “exact” line and round according to your assignment or industry requirement.

Common questions

What is the difference between weight and mass in this calculator?

In physics, mass is the amount of matter and weight is the force of gravity on that mass. In day-to-day situations, scales and labels use “weight” when they really mean mass under Earth gravity. This calculator treats them the same because the unit conversions (grams to pounds, kilograms to ounces, and so on) are defined as relationships between units, not as measurements of gravity.

Why do you show a two-decimal result and an exact result?

Two decimals is easy to read and is usually enough for decisions like comparing package sizes, estimating shipping weight, or tracking body weight. The exact line is there for cases where rounding could matter, such as recipe scaling, converting supplements in milligrams, or checking calculations in schoolwork.

How many grams are in a kilogram, and how many pounds are in a kilogram?

There are 1,000 grams in a kilogram. A kilogram is a bit more than two pounds. If you want the exact conversion, use this calculator with 1 kilogram as the input and convert to pounds, and you will see the precise value immediately.

What is the difference between ounces and pounds, and when should I use each?

Ounces and pounds are both common in the imperial and US systems. Ounces are typically used for smaller weights (like ingredients, small packages, or nutrition serving sizes). Pounds are used for larger weights (like body weight, heavier parcels, or bulk items). If you are not sure, use the unit printed on the label as your “from” unit.

Which “ton” should I choose: metric ton, US short ton, or imperial long ton?

Metric ton (also called a tonne) is used in most countries and is based on kilograms. US short ton is commonly used in the United States for industry and shipping references. Imperial long ton appears in some older UK contexts and in certain maritime or historical references. If your source is US-based and says “ton” without extra wording, it is often the US short ton, but you should confirm from the context if accuracy matters.