Metric & Imperial Conversion
Understand and use approximate equivalences between metric units and common imperial units (inches, pounds, pints)
What a learner can do afterwards
- State that 1 inch ≈ 2.5 cm and use this to estimate length in inches
- Know that 1 kg ≈ 2.2 pounds and estimate a person's weight in pounds
- Convert approximately between litres and pints (1 litre ≈ 1.75 pints)
1 · Read
Some places measure in metric units, like centimeters, kilograms, and litres. Other places also use imperial units, like inches, pounds, and pints. Both measure the same real-world sizes, just with different numbers. You don't need to be exact. A close estimate is enough.
A baby weighs 7 pounds. To estimate kilograms, divide by about 2.2: 7 divided by 2.2 is close to 3.2. So a 7-pound baby weighs a little over 3 kg.
Quick trick: to turn kilograms into pounds, double the number, then add a bit more. To turn litres into pints, add three quarters of the number you started with.
Remember the three swaps: about 2.5 cm to an inch, about 2.2 pounds to a kilogram, and about 1.75 pints to a litre.
2 · Watch
Take it off screen
Where it sits
Learn first
This opens up
Where this leads
18 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.