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Units of Weight Conversion in the Metric System

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How to Convert kg to g, g to mg: Step-by-Step Metric Weight Formulas

The concept of Units Of Weight Conversion Formulas Metric is vital for understanding measurements in science, maths, and daily life. Learning to convert between kilograms, grams, and milligrams helps students perform well in school exams and competitive tests, and is essential in everyday situations like cooking or shopping.


Understanding Metric Units of Weight

The metric system is a decimal-based standard for measuring quantities, with weight (sometimes called mass) as one of the main quantities measured. The most common metric units of weight are:


  • Milligram (mg) – the smallest commonly used unit (1 mg = 0.001 g)
  • Centigram (cg) – equal to 0.01 gram
  • Decigram (dg) – equal to 0.1 gram
  • Gram (g) – the basic unit of weight
  • Dekagram (dag) – 10 grams
  • Hectogram (hg) – 100 grams
  • Kilogram (kg) – 1000 grams (main unit for daily and scientific use)
  • Tonne (t or metric ton) – 1000 kilograms (used for very large weights)

Unit Symbol Equivalent in Grams
Milligram mg 0.001 g
Centigram cg 0.01 g
Decigram dg 0.1 g
Gram g 1 g
Dekagram dag 10 g
Hectogram hg 100 g
Kilogram kg 1000 g
Tonne (Metric Ton) t 1,000,000 g

Metric Weight Conversion Formulas

Conversions in the metric system rely on multiplying or dividing by powers of 10. Use these simple formulas:


  • To convert a larger unit to a smaller unit, multiply (e.g., kg to g: multiply by 1000)
  • To convert a smaller unit to a larger unit, divide (e.g., mg to g: divide by 1000)
From To Multiply/Divide By Formula Example
Kilograms (kg) Grams (g) × 1000 kg × 1000 = g
Grams (g) Kilograms (kg) ÷ 1000 g ÷ 1000 = kg
Grams (g) Milligrams (mg) × 1000 g × 1000 = mg
Milligrams (mg) Grams (g) ÷ 1000 mg ÷ 1000 = g
Kilograms (kg) Milligrams (mg) × 1,000,000 kg × 1,000,000 = mg
Milligrams (mg) Kilograms (kg) ÷ 1,000,000 mg ÷ 1,000,000 = kg

Metric Weight Conversion Chart

This chart summarizes the relationships among metric weight units for easy conversion:


Unit To Next Larger Unit To Next Smaller Unit
Milligram (mg) 1 mg = 0.001 g 1 mg = 1 mg
Gram (g) 1 g = 0.001 kg 1 g = 1000 mg
Kilogram (kg) 1 kg = 0.001 t 1 kg = 1000 g
Tonne (t) - 1 t = 1000 kg

Worked Examples

Example 1: Convert 2400 g to kg

  1. Use the formula: kg = g ÷ 1000
  2. Calculation: 2400 ÷ 1000 = 2.4
  3. Answer: 2.4 kg

Example 2: Convert 3.5 kg to mg

  1. First, convert kg to g: 3.5 × 1000 = 3500 g
  2. Then, convert g to mg: 3500 × 1000 = 3,500,000 mg
  3. Answer: 3,500,000 mg

Example 3: Convert 12500 mg to g

  1. Use the formula: g = mg ÷ 1000
  2. Calculation: 12500 ÷ 1000 = 12.5
  3. Answer: 12.5 g

Practice Problems

  • Convert 0.8 kg to grams.
  • Convert 5400 mg to grams.
  • Convert 7.25 g to milligrams.
  • Convert 200000 mg to kilograms.
  • Convert 0.03 tonnes to kilograms.

Common Mistakes to Avoid

  • Confusing when to multiply or divide by 1000 (e.g., g to kg is divide, not multiply).
  • Forgetting to include units in answers (e.g., writing 12 instead of 12 g).
  • Miscalculating zeros and decimal places, especially when converting mg and kg.
  • Using imperial instead of metric units in exams focused on the metric system.

Real-World Applications

Weight conversion in the metric system has many uses:

  • Cooking recipes that require precise amounts (like 250 g of flour).
  • Medicine dosages measured in mg or g.
  • Grocery shopping—buying fruits and vegetables in kg and g.
  • Science labs and projects where accurate measurement is critical.
  • International trade and shipping (converting tonnes to kilograms).

At Vedantu, we make learning metric weight conversions simple by offering visual charts, stepwise examples, and practice tests. For more on measurements, visit our Complete Guide to Conversion of Units and Metric Conversion Chart pages.


In this lesson, we explored Units Of Weight Conversion Formulas Metric, including all major metric units, formula tables, and worked examples. Understanding these conversions makes maths, science, and daily problem-solving much easier. Mastering these skills ensures success in school and beyond.


FAQs on Units of Weight Conversion in the Metric System

1. How to convert metric units of weight?

To convert between metric units of weight, multiply or divide by powers of 10 using the appropriate conversion factor. For example, to convert grams to kilograms, divide by 1000; to convert kilograms to grams, multiply by 1000.

2. What are the units for weight in the metric system?

The most common metric units of weight are: milligram (mg), centigram (cg), decigram (dg), gram (g), dekagram (dag), hectogram (hg), kilogram (kg), and tonne (t). These units are all based on the gram and related by powers of ten.

3. What are the 7 metric units of weight?

Seven commonly used metric units of weight are: milligram (mg), centigram (cg), decigram (dg), gram (g), dekagram (dag), hectogram (hg), and kilogram (kg). The tonne (t) is also frequently used for larger weights.

4. How do you convert grams to kilograms and milligrams?

To convert grams (g) to kilograms (kg), divide by 1000. To convert grams (g) to milligrams (mg), multiply by 1000.

5. Where can I find a metric weight conversion table?

A metric weight conversion table is readily available online and in many textbooks. It shows the conversion factors between all the metric units of weight, such as grams, kilograms, and milligrams, making conversions quick and easy.

6. Why do metric conversions always use multiples of 10?

The metric system is a decimal system, meaning it's based on multiples of 10. This makes conversions simple because you only need to multiply or divide by powers of 10 (10, 100, 1000, etc.), unlike the imperial system.

7. How do errors in decimal placement affect weight conversions?

Errors in decimal placement during metric weight conversions can lead to significantly inaccurate results. For example, misplacing a decimal point when converting grams to kilograms could result in an answer that's off by a factor of 10 or even 1000.

8. Why is it important to write the correct units in answers?

Writing the correct units (e.g., kg, g, mg) in your answers is crucial because it shows you understand the context of the calculation and prevents errors in both calculations and real-world applications. Omitting or using wrong units can lead to incorrect interpretations.

9. How to convert kg to g to mg?

To convert kilograms (kg) to grams (g), multiply by 1000. To then convert grams (g) to milligrams (mg), multiply by 1000 again. Therefore, to convert directly from kg to mg, multiply by 1,000,000.

10. What are the common mistakes in metric conversion?

Common mistakes in metric conversions include: incorrect placement of the decimal point; using the wrong multiplication/division factor (e.g., multiplying instead of dividing); and forgetting to include the correct units in the final answer. Always double-check your work!

11. What is the metric system of weight?

The metric system of weight is a decimal-based system using the gram (g) as its base unit. Larger and smaller units are derived by multiplying or dividing by powers of 10, making conversions straightforward. Common units include the kilogram (kg), milligram (mg), and tonne (t).