Convert km² to m² square kilometres ↔ square metres Free Online Secure
Type a value in square kilometres and read it in square metres at once. The factor is exact by definition, the arithmetic happens in your browser, and nothing is sent anywhere.
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Common values — Convert km² to m² (square kilometres ↔ square metres)
| km² | m² |
|---|---|
| 1 | 1000000 |
| 2 | 2000000 |
| 3 | 3000000 |
| 5 | 5000000 |
| 10 | 10000000 |
| 20 | 20000000 |
| 50 | 50000000 |
| 100 | 100000000 |
Where these units come from
Square units need no definition of their own: a square metre is a metre by a metre, and everything follows from the length. The land measures are older and stranger. The acre began as the land a yoke of oxen could plough in a day, which is why it was long and thin rather than square — one chain by one furlong, 4840 square yards. The hectare and the are came out of the French Revolution, when land had to be measured in something decimal; neither belongs to the International System, but both were kept for land because a hectare is a comfortable size to picture and a square metre is not. Since the 1959 agreement on the yard, the acre is exactly 4046.8564224 square metres, so the conversions on this page are exact rather than approximate.
Where you meet them
Square metres price flats, size carpets and decide how much paint a wall needs; square feet do the same work in the United States and in much of the property market worldwide. Hectares belong to farmland, forests and planning permissions; acres to land deeds in the English-speaking world. Square kilometres and square miles are for countries, lakes and fires. Square centimetres and square millimetres live in workshops, on datasheets and anywhere a cross-section matters.
Questions people ask
How big is a square kilometre?
A square one kilometre on each side, which is 100 hectares or 1,000,000 square metres. Central Park in New York covers about 3.4 square kilometres, and the whole of Monaco about 2. It is the natural unit for countries, lakes, forests and cities, where the figures in square metres would run to many digits.
How big is a square metre in practice?
A square one metre on each side. A standard interior door is about 1.8 square metres, a single bed about 2 and a small bathroom around 4. Floor space, paint coverage and property prices are usually quoted per square metre, so a rough feel for the size helps you judge whether a listed figure is generous or tight.
Is the answer exact?
Where both units are defined in terms of one another by whole numbers, yes — the page says so above the figure, and the only rounding is in how many digits are shown. Where the ratio has no finite decimal, the page shows twelve significant digits and says the relation is approximate rather than pretending otherwise.
Does anything I type leave my device?
No. The arithmetic runs in your browser; nothing is uploaded and there is no server to upload it to. Load the page once and it keeps working with the network switched off.
A million square metres in every square kilometre
The square kilometre is the unit of countries, counties and large lakes, but physics, engineering and planning formulas are written for square metres: rainfall in litres per square metre, sunshine in watts per square metre, people per square metre in a crowd. To convert km² to m² you multiply by 1,000,000, moving the decimal point six places to the right. So 2.5 km² is 2,500,000 m² and 0.04 km² is 40,000 m². This page multiplies as you type, and the text below shows where the conversion matters, from solar farms to stadium crowds and city densities.
You will find the rule with worked examples, short profiles of both units, a comparison, a long tour of real situations and a list of the mistakes people make most often. The calculation runs in your browser and nothing you type is sent anywhere.
How to convert km² to m²: multiply by 1,000,000
The rule
One square kilometre equals exactly 1,000,000 square metres. To convert km² to m², multiply the square kilometres by one million, which means moving the decimal point six places to the right. So 1 km² is 1,000,000 m², 0.75 km² is 750,000 m² and 12.4 km² is 12,400,000 m². To go back, divide square metres by a million.
Worked examples
Central Park has 3.41 km², 3,410,000 m². Monaco has 2.02 km², 2,020,000 m². The Vatican City has 0.44 km², 440,000 m². When the square kilometre figure has fewer than six decimals, fill with zeros: 0.5 km² is 500,000 m².
Why six places
A kilometre is 1,000 metres, so a square kilometre is 1,000 by 1,000 metres, which is one million. The factor is the square of a thousand. People often use 1,000 by mistake, which gives an answer a thousand times too small.
A quick check
The square metre is the small unit, so the number grows by six digits. If your “convert km² to m²” calculation produced a number with only three extra digits, you used the length factor.
The square kilometre
One thousand metres on a side
The square kilometre is the area of a square 1,000 metres by 1,000 metres, a million square metres, a hundred hectares or 0.386 square miles. It is the unit for countries, regions and lakes, and the basis of population density in people per square kilometre.
Where it appears
Atlases, government statistics, geography books, news reports about floods, fires and migrations.
The square metre
The SI unit of area
The square metre is the area of a square one metre by one metre, 10.76 square feet. It is the unit of rooms, flats, building plots and many physical formulas. When large areas are converted into square metres, numbers reach seven, eight or nine digits.
Where it appears
Formulas for energy, rainfall, density, drag, pressure and heat transfer all use square metres. Land registers and building permits use them for plots.
Square kilometre and square metre compared
One square kilometre holds a million square metres. The two units sit at opposite ends of the everyday scale: the square kilometre for regions, the square metre for rooms. The hectare, 10,000 m², and the are, 100 m², fill the gap.
The conversion has no rounding problem, but the number of zeros is a trap. Six zeros instead of three change the result a thousand fold. Always write the answer with a thousands separator, so you can count digits at a glance.
Where the conversion appears
Crowd density at an event
A festival field of 0.12 km², 120,000 m², can hold 120,000 people at one per square metre, and a safe maximum of about 2 people per square metre in dense standing areas can be applied to a part of the field. Safety managers use square metres for the density and square kilometres only when they describe the whole venue, so a “convert km² to m²” calculation is the first step.
Solar insolation
At noon, the sun delivers about 1,000 watts per square metre. A square kilometre therefore receives 1,000 megawatts, one gigawatt. A solar farm covering a quarter of it with 20 per cent efficient panels produces 50 megawatts at the peak. The energy industry converts areas to square metres to apply such figures.
City density
Manhattan has about 28,000 people per square kilometre, which is 36 square metres of land per person. Hong Kong has 6,800 per square kilometre, 147 m² per person. Mumbai has 21,000 per km², 48 m² each. The number of square metres per person is easy to picture, and a conversion produces it.
Rain on a region
A shower of 20 millimetres on 100 km² delivers 2 million cubic metres of water, 2 billion litres. The calculation is 100 million square metres times 0.02 metres. Hydrologists multiply the area in square metres by the depth in metres to get volume, and so the first step is a conversion of the area.
Farm yields and field sizes
A wheat yield of 7 tonnes per hectare is 700 grams per square metre. A district of 200 km², 200 million m², with 40 per cent under wheat gives 56,000 tonnes. The area of the district comes in square kilometres, the yield per hectare, and the calculation passes through square metres.
Light pollution and sky glow
A city of 100 km² emitting a lighting power of 5 watts per square metre of urban surface radiates 500 million watts, half a gigawatt. Astronomers use area and radiated flux to model sky glow, and the area enters in square metres.
Heat islands in cities
A city district of 25 km² covered 60 per cent by dark surfaces, 15 km², 15 million m², can absorb enormous amounts of solar energy. Urban climate studies measure the area of roofs, roads and parks in square metres, then add them up and give totals in square kilometres, so the unit conversion runs both ways.
Mapping software and GIS
GIS programs compute area in the unit of the coordinate system, usually square metres. A polygon of 12.5 million m² is displayed as 12.5 km² in a report. A user who exports a table without checking the unit may mix columns, so a “convert km² to m²” calculation is a quick way to check any figure.
Rounding
The conversion is exact. Give as many significant figures as the source: 2.02 km² is 2,020,000 m², not 2,020,000.0. If the source says about 2 km², write about 2 million square metres. Do not write more digits than the measurement supports.
Spreadsheet use
Write square kilometres in column A and =A2*1000000 in column B. For the reverse use =B2/1000000. Format with a thousands separator so seven or eight digits are readable. A column with =A2*100 gives hectares.
Teaching the idea
Mark a square of 1 metre on the floor, then ask students to imagine 1,000 of them in a row, which is a kilometre of length, and then 1,000 rows of 1,000, a million squares. The picture explains why the factor has six zeros.
Seas and oceans
The Mediterranean covers about 2.5 million km², 2.5 trillion m². The Baltic has 377,000 km², 377 billion m². The North Sea 570,000 km², 570 billion m². Oceanographers use square kilometres for surface and cubic kilometres for volume, while formulas for evaporation and heat exchange use square metres.
A sense of scale
A square kilometre is the area of 140 football pitches, or about 3,800 tennis courts, or a square whose side is a 12 minute walk. Compared with this, a house plot of 500 m² is 0.0005 km², a tiny speck. Such comparisons help you check that a result of a “convert km² to m²” calculation makes sense.
Shipping and container yards
The port of Rotterdam occupies about 126 km², 126 million m², yet a single container terminal may take 1 km², one million m², and stack boxes five high. A standard 40 foot container has a footprint of 29 m², so one square kilometre could hold around 34,000 of them on the ground, and 170,000 stacked. Port economists mix both units, and a “convert km² to m²” calculation makes the comparison straightforward.
Wind farms and their footprints
An offshore wind farm may lease 400 km² of seabed, 400 million m², yet the turbine bases themselves occupy less than 0.1 per cent of that, under 400,000 m². Developers state the lease in square kilometres and the foundations in square metres, so comparing them needs a “convert km² to m²” calculation.
Golf courses and parkland
An 18 hole golf course takes about 0.5 to 0.8 km², 500,000 to 800,000 m². A city park of 2 km² has 2,000,000 m², room for 280 football pitches. Land managers use hectares in contracts and square kilometres in strategic documents, but use square metres when they calculate irrigation, mowing or fertiliser, so a conversion occurs often in practice.
Tourist crowds and beaches
A beach of 1 km length and 50 m width has 50,000 m², 0.05 km². At 5 m² per sunbather it holds 10,000 people. Beach safety plans use square metres to set limits, while tourism boards describe the coast in kilometres, so planners do the conversion on the back of an envelope.
Agricultural land in national accounts
A country with 120,000 km² of farmland has 120 billion m² of it, and with 10 million people each has 12,000 m² of farmland, 1.2 ha. That ratio is a measure of food security, and nutrition researchers and economists use it, so figures pass from km² to m² and back before the indicator is published.
Reading maps at different scales
On a map at 1:100,000, one square centimetre represents one square kilometre, a million square metres. On a map at 1:10,000, a square centimetre represents 10,000 m², a hectare. A hiker who knows these two anchors can read areas directly, and convert them with a “convert km² to m²” calculation when necessary.
Comparing countries by area per person
Divide a country's area in square metres by its population and you get the land per head. Canada has 9.98 million km² and 40 million people, so 250,000 m² per person, a quarter of a square kilometre. Japan has 378,000 km² and 124 million, 3,050 m² each. Bangladesh has 148,000 km² and 170 million, 870 m². Such figures give a direct idea of crowding, and the first step is to turn square kilometres into square metres, which is exactly what this page does.
A short list to remember
One tenth of a square kilometre is 100,000 m², a quarter is 250,000, a half is 500,000, and three quarters are 750,000. Ten square kilometres are ten million square metres. With these anchors you can estimate any result at a glance, and then use the converter to confirm the digits. Keep the unit next to every figure so that nobody reading your table can mistake square metres for square kilometres.
Evaporation from lakes and reservoirs
A reservoir of 10 km², 10 million m², loses about 5 mm of water on a hot day, which is 50,000 m³. Over a summer of 90 days at 4 mm, the loss reaches 3.6 million m³. Water managers calculate such losses in square metres and cubic metres, though the reservoir is described in square kilometres.
Hurricanes and storm areas
A hurricane with a radius of 200 km covers about 125,600 km², 125.6 billion m². Rainfall of 100 mm over this area would deliver 12.5 billion cubic metres of water. Meteorologists give storm sizes in square kilometres but compute rainfall volumes in cubic metres from square metres.
Large cities and their built areas
The built up area of Greater London is about 1,570 km², 1.57 billion m². Paris has 105 km², 105 million m². Tokyo's urban area is 13,500 km², 13.5 billion m². City planners state areas in square kilometres and densities in people per hectare or per square kilometre, while calculations of green space and runoff need square metres.
Sports stadiums in a city grid
A stadium site of 0.2 km² has 200,000 m². A city of 100 km² has 500 such sites. A football pitch of 7,140 m² is 0.00714 km². These comparisons help planners decide how much land a project requires, and show how small even a large stadium is compared with a city.
Airports and runways
Heathrow covers about 12.3 km², 12.3 million m². A runway of 3.9 km by 50 m has 195,000 m², about 1.6 per cent of the airport. Airport authorities give site area in square kilometres and surfaces such as runways and aprons in square metres, so a “convert km² to m²” calculation appears in airport planning.
National parks and wildlife density
A national park of 3,000 km², 3 billion m², with 600 elephants has one elephant per 5 km², one per 5 million m². Ecologists express density in animals per square kilometre, but the home range of a single animal may be tens of square kilometres, so conversion to square metres rarely helps, though it shows the scale.
Ice and snow on glaciers
A glacier of 50 km², 50 million m², with an average thickness of 100 metres holds 5 billion m³ of ice. If it loses one metre of thickness in a year, it loses 50 million m³. Glaciologists convert area into square metres to compute such volumes, and publish areas in square kilometres for maps.
More values for convert km² to m²
A longer list of conversions
If the value you need is not in the first list, these further conversions may be close enough to read off directly:
- 0.1 km² = 100,000 m²
- 0.5 km² = 500,000 m²
- 3 km² = 3,000,000 m²
- 4 km² = 4,000,000 m²
- 7 km² = 7,000,000 m²
- 15 km² = 15,000,000 m²
- 20 km² = 20,000,000 m²
- 75 km² = 75,000,000 m²
- 200 km² = 200,000,000 m²
- 500 km² = 500,000,000 m²
- 2,000 km² = 2,000,000,000 m²
- 10,000 km² = 10,000,000,000 m²
Mistakes when you convert km² to m²
Multiplying by 1,000
That is the length factor. For area, multiply by 1,000,000.
Dividing instead of multiplying
The square metre is much smaller, so the number grows. If 5 km² became 0.000005, you divided.
Losing zeros
A million has six zeros. Count them twice before sending a report.
Quick answers
How many square metres in a square kilometre?
1,000,000.
How do I convert km² to m²?
Multiply by 1,000,000.
What is 0.5 km² in m²?
500,000 m².
How many hectares in a square kilometre?
100.
Does my number leave my device?
No. The calculation runs in your browser.
Related pages and a last word
If you work with land and area, these conversions are close at hand: Convert km² to ha, Convert km² to mi², Convert ares to m², Convert yd² to m², Convert m² to yd², Convert km to mi, Convert mi to km, Convert °C to °F, Convert °F to °C. The reverse of this page is Convert m² to km².
In short, to convert km² to m² multiply by 1,000,000, remember that the factor is the square of 1,000, and count the zeros with care. Your number stays on your device: nothing is uploaded and no account is needed.