Convert cm to m centimetres ↔ metres Free Online Secure
Type a value in centimetres and read it in 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 cm to m (centimetres ↔ metres)
| cm | m |
|---|---|
| 1 | 0.01 |
| 2 | 0.02 |
| 3 | 0.03 |
| 5 | 0.05 |
| 10 | 0.1 |
| 20 | 0.2 |
| 50 | 0.5 |
| 100 | 1 |
Where these units come from
The metre was first defined in 1793 as a ten-millionth of the distance from the equator to the North Pole — a definition nobody could check without surveying a quarter of the planet. It has been redefined four times since, each time to something steadier: a platinum bar, then a prototype kept in Paris, then a wavelength of krypton light, and since 1983 the distance light travels in vacuum in 1/299,792,458 of a second. The inch stopped being a separate thing in 1959, when six countries agreed to define it as exactly 25.4 mm. That agreement is why every conversion on this page between a metric and an imperial length is exact rather than measured: both sides now descend from the same definition.
Where you meet them
Millimetres are the working unit of engineering drawings and of anything made in a workshop; centimetres belong to tailoring, furniture and school rulers; metres to rooms, fabric and running tracks. Feet and inches survive in aviation altitudes worldwide, in American and British construction, and in the diagonal of every screen you have ever bought. Nautical miles are not a quaint survival — one is a minute of latitude, which is why ships and aircraft still navigate in them.
Questions people ask
Where is the centimetre used in everyday life?
For anything a person measures against their own body: height, clothing sizes, the length of a sleeve, the width of a shelf, the dimensions of a parcel. A centimetre is roughly the width of a fingernail, which makes it easy to picture. It is large enough to avoid long strings of digits and small enough that you rarely need a decimal.
How is the metre defined today?
As the distance light travels in a vacuum in 1/299,792,458 of a second. The definition has been in place since 1983 and ties the metre to the speed of light, which is itself fixed at exactly 299,792,458 metres per second. The old platinum bar in Paris no longer defines anything.
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.
Heights, rooms and rolls of fabric: when you have to convert cm to m
The centimetre is how people measure themselves, their furniture and their fabric, while the metre is how they measure rooms, roads and jumps. A passport says 178 cm, a flat listing says the living room is 4.2 metres wide, a pattern asks for 250 cm of cloth and a hardware shop sells cable by the metre. Whenever the figure in your hand is in one unit and the figure on the page is in the other, you have to convert cm to m. This page does it at once: type a length in centimetres and read it in metres, to as many places as the number needs.
The sum is the easiest in the whole metric system, a division by a hundred, and this page exists because the easy sums are the ones we do carelessly. People move a decimal point one place too few or too many, drop a zero from a price or a length, or confuse metres with millimetres. The text below gives the rule, four worked examples, a short biography of both units, the places where the conversion appears and a checklist of mistakes.
The rule for convert cm to m
Divide by one hundred
One metre contains exactly 100 centimetres, so a length in centimetres is divided by 100 to give metres. 250 cm is 2.5 m; 75 cm is 0.75 m; 1,830 cm is 18.3 m; 5 cm is 0.05 m. In practice, move the decimal point two places to the left and, if the number has fewer than two digits before the point, add zeros as needed.
Four worked examples
A person 178 cm tall is 1.78 m. A wall 420 cm wide is 4.2 m. A swimming pool lane of 2,500 cm is 25 m. A pencil 19 cm long is 0.19 m. The pattern never changes, and the answer has the same digits as the question with a different decimal position.
In your head
Cover the last two digits: 1,230 cm becomes 12.30 m. When the number has only two digits or fewer, put a zero point in front: 45 cm is 0.45 m. A useful check: a person's height in centimetres should come out between 1 and 2 metres, and a room between 2 and 10 metres. If it does not, you have moved the point the wrong way.
Significant figures
Keep as many digits as the measurement deserves. A tape reading of 182.5 cm is 1.825 m, not 1.8250 m. Report the final result to the same precision as the original reading.
The centimetre
A hundredth of a metre
The centimetre is the unit of everyday human scale: your hand is about 18 cm, a pen about 14, a credit card 8.6 cm wide. It is small enough to avoid fractions for objects in the house and large enough that numbers stay manageable. The prefix centi- comes from the Latin for a hundred, and the symbol is cm.
Where you meet it
Height charts, clothing patterns, kitchen worktops, bookshelves and fabric widths all use centimetres. Doctors record babies' length in centimetres, and a school ruler shows them in thin lines and numbers.
The metre
The base unit of length
The metre is the base unit of length in the International System of Units. Since 1983 it has been defined as the distance light travels in a vacuum in 1/299,792,458 of a second, so it rests on a constant of nature. Before that it was defined by a platinum bar in Paris, and before that as a ten-millionth of the distance from the North Pole to the equator.
Where you meet it
Roads, sports tracks, rooms, cables, ropes and the height of buildings are measured in metres. A metre is roughly a long stride or the height of a kitchen counter, and the word comes from the Greek metron, a measure. The symbol is m.
Centimetre and metre compared
A metre is 100 centimetres, so a number of metres is a hundredth of the number of centimetres. A tall man is 190 cm or 1.90 m; both mean the same. A good rule is to use centimetres for objects up to about a metre and metres beyond that, though plenty of people say a table is 120 cm and a room 4 m in the same breath.
If your reader is a professional, such as a builder, an architect or a tailor, adopt the habit of their trade. Builders often use millimetres on plans, architects metres, and tailors centimetres. When you convert cm to m, write the new unit clearly, and never leave a bare number.
Where people convert cm to m
Building and decorating
Floor plans give room dimensions in metres, while shops sell flooring, paint and wallpaper by area or length. A room of 380 cm by 450 cm is 3.8 m by 4.5 m, an area of 17.1 m². A roll of wallpaper 53 cm wide and 10.05 m long covers about 5 m². A skirting board of 240 cm is 2.4 m, and a standard door 203 cm high is 2.03 m. Before you buy, convert cm to m for every measurement and add 10 per cent for waste.
Sport and fitness
Athletics uses metres for tracks and jumps and centimetres for the height of a high jump bar: 2.45 m is the world record, 245 cm. A swimming lane is 25 or 50 m, a football pitch about 105 m by 68 m. Gym equipment, such as a yoga mat of 183 cm by 61 cm, is 1.83 m by 0.61 m. Runners often convert to check the length of a repeat: 400 m is a lap of the track.
Sewing and fabric
Fabric shops sell cloth by the metre, while patterns list centimetres. A dress that needs 230 cm of fabric asks for 2.3 m; round up to 2.5 m to allow for shrinkage and matching of patterns. Curtain widths, ribbon lengths and zip sizes all come in centimetres, and the order is placed in metres.
Travel and transport
Airlines quote cabin bag dimensions in centimetres, such as 55 × 40 × 20; a road bridge height is in metres, like 4.2 m; and a car's length of 450 cm is 4.5 m. A trailer, a ladder, a roof box or a rack must fit the space available, so conversions matter. Electric scooter and bike lanes have widths in metres. When you convert cm to m for a vehicle, measure twice and add a safety margin.
The long road to the metre
Before the metre
Until the late eighteenth century, every region had its own foot, ell and fathom. A merchant travelling from Paris to Lyon met different lengths, and tailors argued about whose ell was fairer. Scientists complained that such a patchwork blocked trade and discovery. The revolution of 1789 created the political will to replace it with something universal.
Measuring the Earth
The Academy of Sciences proposed a unit based on the Earth itself, one ten-millionth of the distance from the pole to the equator. Two astronomers, Delambre and Méchain, measured the arc between Dunkirk and Barcelona over six years, surviving prison, war and illness. The platinum bar they produced in 1799 became the standard metre. Modern measurements show that it is 0.2 millimetres short of the planned figure, but the definition was changed to the speed of light long ago, and nobody minds.
The centimetre follows
The centimetre was always part of the plan. The founders wanted a decimal ladder, with names from Latin for the small steps and Greek for the large ones. A hundredth of a metre was convenient for human objects, and it quickly became the favourite of schools, tailors and doctors. When you convert cm to m you are moving one rung down a ladder designed 230 years ago.
Taking the measurement well
Straight and flat
Most measurement errors come from the way the tape is held, not from arithmetic. Keep the tape straight and flat against the object, avoid sag over long distances, and read the scale with your eye directly above the mark. When two people measure, the one at the far end should hold the tape taut and at the same height as the near end. A string or a chalk line helps over uneven ground. Before you convert cm to m, be sure the original figure is something you would bet on.
Measure twice, write once
Take each measurement twice and write the result with its unit as soon as you have it. If the two readings differ by more than a millimetre, measure a third time. Photograph the tape against the object as a record. A minute spent on this saves a trip back to the shop.
Instruments and accuracy
Tapes, rulers and lasers
A school ruler is accurate to a millimetre. A tailor's tape stretches slightly with use and should be checked against a rigid ruler once a year. A steel building tape is good to a millimetre over five metres. Laser meters measure rooms from 0.05 to 100 metres with an error of 1.5 mm. The cheapest instruments are often adequate for household work, and the dearest are justified only when tolerances are tight.
Reading and recording
Record a length as soon as you measure it, with the unit, and note the end points. If you need to convert cm to m from several readings, convert each only at the end and use the unrounded figures in between. Photographs of the tape against the object are a cheap record.
Temperature and materials
Materials expand with heat: a steel tape grows by about 0.012 mm per metre for every degree of temperature rise, and a wooden board swells with humidity. For ordinary use these effects are tiny, but for a precision job in a cold workshop or a hot room, allow for them.
Typical lengths to remember
Anchors from the body and the home
A newborn is 50 cm long, a toddler 85 cm at two years, an adult woman averages about 165 cm and a man about 178 cm in many countries. A sofa is about 200 cm, a dining table 160 to 180 cm, a bed 200 cm, a door 203 cm, a kitchen counter 90 cm and a bathtub 170 cm. In metres: 0.5, 0.85, 1.65, 1.78, 2.0, 1.6 to 1.8, 2.0, 2.03, 0.9 and 1.7. With these anchors you can judge whether a result is plausible.
Large numbers
A bus is 12 m, a tennis court 23.77 m, an Olympic pool 50 m, a football pitch 105 m, and the Eiffel Tower 330 m. Expressed in centimetres, those figures are 1,200, 2,377, 5,000, 10,500 and 33,000. When numbers have many zeros, it is easy to lose one, which is the best reason to use metres.
Money, pricing and the metre
Prices per metre
Fabric, cable, rope, pipe, fencing and carpet trim are priced per metre, but lengths are often measured in centimetres. A cable that costs 1.80 per metre and measures 275 cm costs 2.75 × 1.80 = 4.95. Shops usually round up to the next 10 cm, so ask. When you convert cm to m for a quote, confirm the unit price and the minimum length.
Online shopping
Product pages list dimensions in either unit, often both, and sometimes inconsistently. A bookcase listed as 180 cm high and 1.8 m high is the same, but a typo of 1.08 m would mean 108 cm. Cross-check any dimension that looks odd by converting it back, and read the size drawing in the images.
Teaching the conversion
For parents and teachers
Children usually meet this conversion between the ages of eight and ten, and a few simple images help. Show a metre stick with its hundred marks and let them count, then cut a ribbon of one metre into ten pieces of ten centimetres each. Ask them to lay a series of objects along the stick and write each length twice, in centimetres and in metres. After a few days, the rule of moving the point two places feels natural. A game that works well is to guess the height of a door, a table or a classmate in centimetres and then convert cm to m to test whether the guess is sensible.
Common stumbling blocks
Pupils often forget that a number written with a comma or point behaves differently in different countries: 1,5 m is one and a half metres in much of Europe, while 1,500 cm in English writing is one thousand five hundred. Teach them to read the unit first and the number second. Another stumbling block is the zero in 0.05: explain that it fills the empty tenths place, so the number is five hundredths and not five tenths.
Real-world size checks
Furniture and fit
Before you buy furniture, measure the door, the stairs and the corridor, and compare them with the product's dimensions. A wardrobe 240 cm tall will not fit under a ceiling of 2.35 m, and a sofa 220 cm long cannot turn a corner in a hall 100 cm wide. Draw a plan in metres, mark the furniture in centimetres and check every clearance. Where you must convert cm to m for a plan, round clearances up by a few centimetres, never down.
Cars and garages
A garage door is often 240 cm wide and 200 cm high, which is 2.4 m by 2.0 m, while a family car is about 180 cm wide, 1.8 m, with mirrors that add 25 cm. That leaves just over 15 cm each side, a narrow margin. SUVs and roof boxes can exceed the height limit of 2.0 m. Check the vehicle's data sheet and your own garage with a tape before you buy.
More values for convert cm to m
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 cm = 0.001 m
- 0.5 cm = 0.005 m
- 3 cm = 0.03 m
- 4 cm = 0.04 m
- 7 cm = 0.07 m
- 15 cm = 0.15 m
- 20 cm = 0.2 m
- 75 cm = 0.75 m
- 200 cm = 2 m
- 500 cm = 5 m
- 2,000 cm = 20 m
- 10,000 cm = 100 m
Mistakes that happen when you convert cm to m
Moving the point only once
Dividing by 10 instead of 100 is common. 250 cm is 2.5 m, not 25 m. A person 25 metres tall is a warning sign that you have slipped.
Confusing metre and millimetre
Mixing m, cm and mm in one list leads to errors of a factor of ten or a thousand. Convert everything to one unit before adding.
Dropping the zero
5 cm is 0.05 m, not 0.5 m. Write the leading zero, and check the order of magnitude: a pencil is not half a metre.
Quick answers
How many centimetres are in a metre?
One hundred.
How do I convert cm to m?
Divide by 100, or move the decimal point two places to the left.
What is 180 cm in metres?
1.8 m.
Is the conversion exact?
Yes, both units are defined from the metre by a power of ten.
Is my number sent anywhere?
No. The calculation runs in your browser and nothing is uploaded.
Related pages and a last word
If you measure often, these conversions are close by: Convert cm to dm, Convert cm to mm, Convert yd to m, Convert nm to m, Convert m to km, Convert °C to °F, Convert °F to °C, Convert L to gal, Convert gal to L. The reverse of this page is Convert m to cm.
In short, to convert cm to m divide by 100, check that the answer is a hundredth of the starting figure and keep the digits your measurement supports. Your number stays on your device: nothing is uploaded, and there is no account.