Converting measurement units
Convert between different units of measure (e.g. kilometre to metre, hour to minute, minute to second, year to month, week to day)
What a learner can do afterwards
- Convert 3 km to 3000 m
- State 2 hours = 120 minutes
- Convert 5 weeks to 35 days
1 · Read
Sometimes the same measurement is written using two different units. A distance of 3 kilometres is exactly the same as 3000 metres, just counted in smaller pieces. To convert, you need to know how many small units make one big unit.
One kilometre equals 1000 metres. To turn 3 km into metres, multiply by 1000: 3 x 1000 = 3000 m.
Moving to a smaller unit? Multiply. Moving to a bigger unit? Divide. Five weeks is 5 x 7 = 35 days, since each week has 7 days.
To convert between units, multiply when the new unit is smaller and divide when the new unit is bigger.
More to read
Converting units of time review (seconds, minutes, and hours)
Time units nest inside each other. 60 seconds make 1 minute. 60 minutes make 1 hour. 24 hours make 1 day. 7 days make 1 week. To change a big unit into a small one, multiply. 2 hours is 2 x 60 = 120 minutes. 5 weeks is 5 x 7 = 35 days. To change a small unit into a big one, divide. 180 seconds is 180 / 60 = 3 minutes. Mixed amounts need two moves: 1 hour 30 minutes is 60 + 30 = 90 minutes. Always finish with the unit name, or the number means nothing.
How to Convert Units With Prefixes: 14 Steps
Metric units use prefixes that tell you the size. Kilo means 1000, so 1 kilometre is 1000 metres and 3 km is 3000 m. Centi means one hundredth, so 100 centimetres make 1 metre. Milli means one thousandth, so 1000 millimetres make 1 metre. To convert, first ask: am I going from big to small or small to big? Big to small means multiply: 5 km is 5 x 1000 = 5000 m. Small to big means divide: 2000 m is 2000 / 1000 = 2 km. Learn the six bridges by heart: km to m, m to cm, cm to mm, hours to minutes, minutes to seconds, and weeks to days.
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2 · Watch
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Where it sits
Where this leads
16 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.