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Contributor: Elephango Editors. Lesson ID: 11338
Explore grams and kilograms as you learn to measure, compare, and calculate metric weight in fun, everyday ways!
What Does It Weigh?
In everyday life, you are surrounded by things you can lift, carry, or pour—each with its own weight.
You won’t see pounds and ounces. Instead, you’ll see grams, kilograms, and milligrams.
Understanding how to use these metric units helps you shop, cook, do science, and make good guesses about how heavy something is—no scale needed!
Understanding Metric Weight
What Is Weight?
Weight tells you how heavy something is. In science, it’s called mass, which means how much matter is inside an object.
The more mass an object has, the more it weighs.
Metric Units of Weight
In the metric system, weight is most often measured in grams (g) and kilograms (kg).
Here’s how they compare.
1 kilogram = 1,000 grams
A gram is very small—about the weight of a paperclip.
A kilogram is much heavier—about the weight of a cantaloupe, a math book, or a small dog.
You may also hear about milligrams, which are used for very tiny weights, like medicine doses or a single grain of salt.
When to Use Grams or Kilograms
Think of these examples.
| Object | Best Unit to Use |
| a paperclip | grams |
| a box of cereal | grams |
| a pair of shoes | kilograms |
| a watermelon | kilograms |
| a tablet of aspirin | milligrams |
If an object is light enough to lift easily with one hand, you’ll probably use grams.
If it’s heavier or bulkier, you’ll use kilograms.
And if it’s tiny or precise, like a vitamin, milligrams are best.
Practice Makes Perfect
Now that you know how the metric system describes weight, you’ll need to estimate and calculate weights in grams and kilograms—just like a baker, doctor, or scientist might!
Head to the Got It? section to practice picking the best unit of weight for real-world objects and solving a few weighty word problems!
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