Measuring Weight With Metric Units

Contributor: Elephango Editors. Lesson ID: 11338

Explore grams and kilograms as you learn to measure, compare, and calculate metric weight in fun, everyday ways!

1To2Hour
categories

Measurement and Data

subject
Math
learning style
Visual
personality style
Golden Retriever
Grade Level
Intermediate (3-5)
Lesson Type
Dig Deeper

Lesson Plan - Get It!

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What Does It Weigh?

  • Have you ever tried to guess the weight of a watermelon or a paperclip?
  • How about a puppy, a backpack, or a handful of sugar?

In everyday life, you are surrounded by things you can lift, carry, or pour—each with its own weight.

  • But what if you’re in a country that uses the metric system?

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

A scientist's gloved hand uses a stainless spatula to transfer a substance into a vial for weighing a sample

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.

A cute pug dog relaxing on a digital scale, showcasing its adorable features in a cozy indoor setting.

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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