Area conversion chart
Area moves the decimal point two steps per prefix - from square kilometres to square millimetres. Edit, print and share.
The area conversion chart in chain form: 1 km² = 100 ha, 1 ha = 10 000 m² and on down to square millimetres. Made for the classroom and home.
| 1 km² | = | 100 ha |
|---|---|---|
| 1 ha | = | 10 000 m² |
| 1 m² | = | 100 dm² |
| 1 dm² | = | 100 cm² |
| 1 cm² | = | 100 mm² |
| 1 km² | = | 1 000 000 m² |
| 1 m² | = | 10 000 cm² |
| 1 m² | = | 1 000 000 mm² |
| 1 dm² | = | 10 000 mm² |
| 1 cm² | = | 0.0001 m² |
How the table works
Every row is a unit conversion: a quantity and unit on the left, the same quantity expressed in another unit on the right. The table is live – drag the handle to reorder, click a row to change the quantity or units, remove rows with the cross and add your own at the bottom.
Everything you change lands in the page address. Copy the link and others open exactly your table – handy when the whole class needs the same sheet. Your changes are also kept in your browser until you reset them, but only there: to share or keep them permanently, the link is what counts.
Print puts the table on a single portrait A4 and Download PDF gives you the same sheet as a file. Print practice sheet gives the table with empty answer cells and name/date lines – the normal printout is the answer key.
The decimal point moves two steps, not one
Area is a surface, length times length – so every prefix step moves the decimal point TWO places instead of one. From metre to decimetre the length jump is ×10, but from square metre to square decimetre it is ×100 (10 × 10). The same pattern holds through the whole chain: square centimetre to square millimetre is also ×100.
Common mistake: assuming 1 m² = 10 dm², the way it works in the length table. The correct answer is 1 m² = 100 dm² – a square metre holds 10 × 10 = 100 squares of 1 dm² each.
The hectare (ha) is an exception in name only, not in the maths: one hectare is a square with 100 m sides, so 100 × 100 = 10 000 m².
Roughly how big?
- A football pitch is roughly 0.7 hectares.
- An average classroom is roughly 60 m².
- A sheet of A4 paper is roughly 6.24 dm² (623.7 cm²).
- A thumbnail is roughly 1 cm².
Frequently asked questions
How many square decimetres are there in a square metre?
1 m² = 100 dm² – two ten-steps in length become one hundred-step in area (10 × 10 = 100).
How many square metres are there in a hectare?
1 ha = 10 000 m² – a square with 100 m sides.
How many square millimetres are there in a square centimetre?
1 cm² = 100 mm², not 10 – the same two-step rule as the rest of the chain.
More tables: Length · Volume · Prefix ladder · Area converter