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Weight Conversion Calculator
From milligrams to megatonnes, calculate mass and weight with ease.Weight Converter
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Updated on September 1, 2025
Our Weight Conversion Calculator is a fast and reliable online tool that allows you to convert between 20 different weight units, including grams, ounces, tons, slugs, pounds, and more. It simplifies weight conversions and saves your time by giving precise results in just a few clicks. In this article, I’ll discuss how the converter works, the units it supports, and the useful features it offers. Let’s get started!About Our Weight Conversion Calculator
Written By
Nadiba Rahman
Reviewed by
Mrinmoy Roy
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What is Weight?
Weight is a measure that tells how heavy something is due to gravity. It depends on two things: how much stuff or matter (or mass) is in the object and how strong the gravity is acting on it. That’s why your weight becomes less on the Moon than on Earth, as there’s less gravity there, even though your body hasn’t changed at all.The formula to calculate weight is:
Weight (W) = Mass (m) × Gravitational Acceleration (g)
Now, what is Mass? Mass is the actual amount of matter in an object. It doesn't change, no matter where you are in the universe. Whether you're on Earth, in space, or on another planet, your mass stays the same.
Weight is measured using different units depending on the country or situation. For example, pounds, ounces, and tons are common in the U.S., while kilograms and grams are commonly used in most other parts of the world.
Conversion Units Available in Our Weight Converter
Here’s a list of all the available units in our weight conversion calculator:- Carats (ct): 1 carat = 0.2 grams, commonly used to measure gemstones and precious metals.
- Cental (c): Used in the U.S. for agricultural products like grain and cotton. 1 cental = 100 pounds.
- Decagrams (dag): Metric unit for small weights. 1 dag = 10 grams.
- Grains (gr): 1 grain = 64.79891 milligrams, often used in measuring small amounts of substances like powder or medicine.
- Grams (g): The basic unit of weight in the metric system.
- Hectograms (hg): Metric unit, often used in food. 1 hg = 100 grams.
- Hundredweights (cwt): Used in the UK and US. 1 hundredweight (US) = 100 pounds (45.359 kg); 1 hundredweight (UK) = 112 pounds (50.8 kg).
- Kilograms (kg): Standard metric unit for most everyday weight calculations. 1 kg = 1000 grams.
- Kilotonnes (kt): Used for measuring large masses. 1 kilotonne = 1,000,000 kilograms.
- Megatonnes (Mt): A very large weight unit. 1 megatonne = 1,000,000,000 kilograms.
- Micrograms (µg): Used in pharmaceutical and scientific measurements. 1 microgram = 0.000001 grams.
- Milligrams (mg): Common for small amounts like medicine. 1 mg = 0.001 grams.
- Nanograms (ng): Used for ultra-small weights. 1 nanogram = 0.000000001 grams.
- Ounces (oz): 1 ounce = 28.3495 grams. It’s common in the U.S. and UK for food and mail.
- Picograms (pg): 1 picogram = 0.000000000001 grams. It is used for extremely small weights.
- Pounds (lb): Popular in the U.S. and UK. 1 pound = 16 ounces or 453.592 grams.
- Slug: A unit used in the imperial system, where 1 slug = 14.6 kilograms.
- Stones (st): 1 stone = 14 pounds (6.35 kg). It is used in the UK for body weight.
- Tonnes (t): It is also called a metric ton, equal to 1000 kilograms.
- Tons (ton): Used mainly in the U.S. 1 ton = 2000 pounds (907.184 kg).
How to Use Our Weight Conversion Calculator?
Using our weight conversion calculator is very easy. Just follow the simple steps below:Select the Conversion Units
Choose the weight units you want to convert from and to.
Enter the Input Weight Value
Enter the weight value you want to convert.
Get Your Result
The calculator instantly displays the converted result in the target unit, and you can copy it with a single click.
Features of Our Weight Conversion Calculator
Our weight converter is designed to make weight conversions quick and simple. You can access all of the features from the settings menu. Here’s how each feature supports your weight conversion measurements:Real-time Multi-unit Conversion
When working with weights, you often need to compare results across different units. Whether you're switching between kilograms (kg), grams (g), milligrams (mg), or larger units like tonnes (t) or kilotonnes (kt), converting one unit at a time can slow you down.Our calculator instantly displays the equivalent values in all supported units as soon as you enter a weight. For example, if you enter 100 kg, the calculator immediately shows the weight in pounds, ounces, grams, and other units.
Flexible Decimal Precision
During weight conversions, even a small inaccuracy can affect the whole results. To avoid this issue, our calculator allows you to adjust the number of decimal places you want in your result.By default, the calculator shows results with 6 decimal places, but you can increase or decrease the precision from 0 to 12 decimal places to match your project’s accuracy requirements.
Rounding Mode Control
Precise rounding is important when calculating weights for shipping or industrial applications. Our tool gives you full control over rounding. You can round values up, down, or turn off rounding completely, depending on how you want to handle decimals. This control helps ensure your weight data aligns perfectly with your calculation needs and minimizes errors.Multiple Number Format
Weight values can range from tiny scales like picograms to massive units like megatonnes. Choosing the right format makes these values easier to read and apply. To support this, our tool offers three different number formats:- Standard Decimal (e.g., 1,234.567 g)
- Scientific Notation (e.g., 1.234567e+3 g)
- Engineering Format (e.g., 1.234567 × 10^3 g)
Integrated Scientific Calculator
Weight conversion often comes after or during other calculations. If you're calculating the total load or finding averages, switching between separate tools for math operations and conversions is inefficient.That’s why our weight converter includes a built-in scientific calculator that allows you to perform math operations directly within the tool. For example, you can add multiple carats (ct) or convert the sum of slugs into pounds (lb), all without leaving the tool.
Thousand Separators Toggle
Large weight values in units like kilograms, tonnes, or pounds can be hard to read when displayed as a continuous string of digits. To improve clarity, our calculator offers a toggle for thousand separators.This feature allows you to display numbers like 1234567.89 kg as 1,234,567.89 kg, which is easier to verify and work with. You can switch this setting on or off based on the formatting requirements of your task.
One-click Unit Swap
Sometimes you need to convert a weight and then quickly check the reverse conversion. Our one-click unit swap feature lets you switch the input and output units instantly. This makes it quick to verify results or compare both directions of a conversion.Clickable and Auto-Saved Conversion History
When you're working on complex weight conversions, it’s important to keep track of your recent conversions. That’s why our tool saves your last 10 conversions automatically, even if you refresh or close the browser.You can open the History tab, click on any previous result, and instantly reuse it. You don’t need to retype anything.
Weight Conversion Table
Click the button below to download the Weight Conversion Chart. Here, you’ll find all the conversion factors for different weight units.
2 Examples of Conversion with Our Weight Converter
To convert weight units accurately, you need to know the original unit, the target unit, and the correct conversion factor (you can refer to the Weight Conversion Chart above for reference). The basic formula is:Value in Target Unit = Value in Source Unit × Conversion Factor
Here are two common examples to show how it works:
Pounds (lb) to Kilograms (kg) Conversion
To convert pounds to kilograms, multiply the value in pounds by 0.453592. For example, to convert 50 lb to kilograms:50 × 0.453592 = 22.6796 kg
Grams (g) to Ounces (oz) Conversion
To convert grams to ounces, multiply the value in grams by 0.035274. For example, to convert 250 g to ounces:250 × 0.035274 = 8.8185 oz
