Converting metric units of mass
Understanding how to convert between metric units of mass, such as grams, kilograms, and milligrams, is essential in everyday life. Whether you're measuring ingredients for a recipe, weighing luggage for a flight, or calculating medication dosages, knowing how to switch between these units ensures accuracy and efficiency. Jump to the questions
Practise now
Convert the following values to the required units.
Topic guide
What this worksheet practises
This worksheet provides practice on converting metric units of mass (weight), specifically milligrams (mg), grams (g), and kilograms (kg). Knowing how to quickly switch between these units is vital for interpreting science experiments, cooking recipes, and everyday measurements.
Key method
Metric conversions for mass are beautifully simple because they all work by multiplying or dividing by 1000.
- To convert from a larger unit to a smaller unit, you multiply by 1000. (For example, moving from kg to g).
- To convert from a smaller unit to a larger unit, you divide by 1000. (For example, moving from mg to g).
- Memorise the basic facts: 1000 mg = 1 g, and 1000 g = 1 kg.
Worked example
Convert 3.2 kilograms into grams.
Step 1: Identify the conversion factor. We are moving from kilograms to grams.
1 kilogram = 1000 grams.
Step 2: Decide whether to multiply or divide. We are going from a larger unit (kg) to a smaller unit (g), so we need more of them. Therefore, we multiply.
Step 3: Perform the calculation.
3.2 × 1000 = 3200.
The answer is 3200 g.
Common mistakes to avoid
A frequent error is moving the decimal point the wrong number of places. Multiplying by 1000 means moving the point three places to the right. 3.2 × 1000 is 3200, not 320. Another mistake is dividing when you should multiply, leading to a tiny number like 0.0032.
Things to remember
Remember the word roots: "kilo" means thousand, so a kilogram is a thousand grams. "Milli" means thousandth, so a milligram is a thousandth of a gram. This logic makes it impossible to forget the number 1000.