What are some exact conversion factors everyone should know?

In one line

The rule

A conversion factor is a number you multiply or divide by to change from one unit to another.

Let's understand it simply

Imagine you are buying vegetables in the market. Sometimes the price is for 1 kilogram, but you only want 250 grams. You need to know how many grams make a kilogram. That number (1000) is your conversion factor. These numbers help you switch between units in maths and science, just like changing money from rupees to paise.

How it works

1. Find the units you have and the units you want.
2. Check the conversion factor between them.
3. Multiply or divide your number by the conversion factor.
4. Write your answer in the new unit.

Some exact conversion factors everyone should know

• Length:
• 1 kilometre (km) = 1000 metres (m)
• 1 metre (m) = 100 centimetres (cm)
• 1 centimetre (cm) = 10 millimetres (mm)
• Mass:
• 1 kilogram (kg) = 1000 grams (g)
• 1 gram (g) = 1000 milligrams (mg)
• Time:
• 1 hour = 60 minutes
• 1 minute = 60 seconds
• Volume:
• 1 litre (L) = 1000 millilitres (mL)
• Temperature:
• Celsius to Kelvin: K = °C + 273.15
• Area:
• 1 square metre (m²) = 10,000 square centimetres (cm²)
• Speed:
• 1 kilometre per hour (km/h) = 5/18 metres per second (m/s)

Where you see it in real life

• Buying rice: You see prices in kilograms, but sometimes you buy in grams.
• Filling petrol: The pump shows litres, but your scooter's tank might be in millilitres.
• Cricket pitch: The length is given in metres, but you might want to know it in centimetres.
• Measuring fever: The thermometer shows °C, but some science books use Kelvin.

Why it matters

• Helps you solve science and maths problems correctly.
• Needed for cooking, shopping, and travelling.
• Used in exams to check your understanding of units.
• Important for jobs in science, engineering, and medicine.

Common mistakes

• Mixing up when to multiply or divide. (Always check if you are going to a bigger or smaller unit.)
• Forgetting to change the unit after converting.
• Using the wrong conversion factor (like mixing up grams and kilograms).

Remember it

"Kilo means 1000, centi means 100, milli means 1/1000."