Convert dm to ft decimetres ↔ feet Free Online Secure
Type a value in decimetres and read it in feet 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 dm to ft (decimetres ↔ feet)
| dm | ft |
|---|---|
| 1 | 0.328083989501 |
| 2 | 0.656167979003 |
| 3 | 0.984251968504 |
| 5 | 1.64041994751 |
| 10 | 3.28083989501 |
| 20 | 6.56167979003 |
| 50 | 16.4041994751 |
| 100 | 32.8083989501 |
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
Does anyone still use decimetres?
Rarely on its own: a decimetre is ten centimetres, and most people jump straight from centimetres to metres. It survives in school lessons and in one important place, the litre, which is exactly one cubic decimetre. That is why a litre of liquid fits in a cube ten centimetres on each side.
Why are aircraft altitudes given in feet?
Because international aviation standardised on feet decades ago and has never had a reason to change. Flight levels are altitudes in hundreds of feet, so level 350 is 35,000 feet. A foot is exactly 0.3048 metres, so converting is exact; a few countries, such as China and Russia, have used metres instead, which is why pilots must know both.
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 Dutch plan for an American builder: how to convert dm to ft
Imagine you have found a beautiful design for a garden bench on a Dutch woodworking site. The board lengths are listed as 15 dm, 6 dm and 4.5 dm, and your lumber yard in the United States sells boards in feet. To buy the right wood you have to convert dm to ft, and this page does it at once: type a length in decimetres and read it in feet. It also gives the result in the form people actually use, a whole number of feet and a leftover in inches, which is how a tape measure in a hardware shop shows it.
The two units come from different worlds. The decimetre is a rung of the metric ladder, a tenth of a metre; the foot is an imperial and American unit of exactly 0.3048 metres. Because the foot is defined in metres, the conversion is exact but not tidy, a division by 3.048. The sections below explain the rule, give worked examples, introduce both units, compare them, describe the situations in which the conversion is needed, and warn about the slips that waste lumber.
The rule for convert dm to ft
The factor
One decimetre is 0.1 metre, and one foot is exactly 0.3048 metres, which is 3.048 decimetres. To convert dm to ft, divide the number of decimetres by 3.048, or multiply it by 0.328084. For example, 10 dm is 3.2808 ft, 15 dm is 4.9213 ft, and 30 dm is 9.8425 ft. The reverse, from feet to decimetres, uses the factor 3.048.
Feet and inches
A workshop tape does not show decimal feet but feet and inches. To get inches, multiply the fractional part of the feet by twelve. 15 dm is 4.9213 ft, which is 4 ft and 0.9213 × 12 = 11.06 inches, so 4 ft 11 in. A board of 6 dm is 1.9685 ft, or 1 ft 11.6 in. Round to the nearest eighth of an inch for woodwork.
Mental shortcut
Divide by three, then take off about one and a half per cent: 30 dm ÷ 3 = 10, minus 0.15 gives 9.85, close to the exact 9.84. The reason is that 3 dm is almost exactly one foot (30 cm against 30.48 cm), so the foot count is a hair smaller than a third of the decimetre count.
Significant figures
Do not give more digits than you started with. If the plan lists 4.5 dm, report 1.5 ft, not 1.4764 ft, unless your saw can cut to a hundredth of a millimetre.
The decimetre
A hand's width
The decimetre is a tenth of a metre, about the width of a hand. It is one of the original metric units, present since the 1790s, and it matters because a cube a decimetre on each side holds one litre. Dutch and Belgian carpenters use it in everyday speech, and school books show it as a rung between the centimetre and the metre.
In the shop
In English-speaking countries the decimetre is rare in daily life, so you will meet it mainly in imported plans, science books and labels.
The foot
Twelve inches
The foot was originally the length of a human foot, which varied. In 1959 the English-speaking countries fixed it at exactly 0.3048 metres, and since then it has been precisely 30.48 centimetres. It is divided into twelve inches, and three feet make a yard. The symbol is ft, or a single prime mark.
In everyday life
In the United States and Britain, people give their height in feet and inches, buy lumber and flooring by the foot, and describe aircraft altitude in feet. Pilots all over the world, even in metric countries, use feet for altitude, and the cruising height of an airliner, 35,000 ft, is about 10,668 m.
Decimetre and foot compared
A foot is about 3 decimetres, a little more: 3.048. So a number of feet is roughly a third of the same length in decimetres. The foot is the longer unit: 10 dm is 3.28 ft, while 10 ft is 30.48 dm. Remember that a hand span of an adult is about one decimetre, and a human foot about 2.5 to 3 decimetres.
For international documents, give both: 15 dm (4 ft 11 in). In a workshop, the unit of the saw wins; if your tape shows feet and inches, convert the whole plan once and write the new numbers on the drawing.
When people need to convert dm to ft
Imported plans and kits
Woodworking, model-making and furniture kits from the Netherlands, Belgium and Germany sometimes give dimensions in decimetres. A kit for a children's playhouse may list a wall of 18 dm by 12 dm. In feet this is 5.9 ft by 3.9 ft. An American builder must convert dm to ft for every dimension before buying material, because boards come in 6, 8, 10 and 12 ft lengths.
Aquariums, terrariums and pet housing
Pet shops in some countries label the length of aquariums in decimetres. A tank of 12 dm is 3.94 ft, a typical 4-foot aquarium; a terrarium of 9 dm is 2.95 ft. Because a litre is a cubic decimetre, decimetres are useful for capacity, but the stand and the shelf are measured in feet. Convert both to be sure the tank fits.
Gardening and landscaping
Plant spacing in European gardening books is sometimes given in decimetres: 4 dm between lettuces is 1.31 ft; 7.5 dm between tomato plants is 2.46 ft. Raised beds of 12 dm width are 3.94 ft, a width that lets you reach the middle from either side. If your supplier sells timber for the borders in feet, convert before ordering.
Travel and luggage
Small items such as a rolled mat, a fishing rod case or a ski pole bag may be listed in decimetres on European sites. A case of 14 dm is 4.59 ft, longer than many airline limits. Check whether your item fits in the vehicle, and ask the seller for centimetres if you are not sure.
The origins of the two units
A decimetre from a revolution
The decimetre belongs to the family of units designed during the French Revolution, when scientists replaced local feet and ells with a decimal system. The metre was defined as a ten-millionth of the quarter meridian through Paris, and its decimal subdivisions followed. The idea was that any person who could multiply by ten could change units.
A foot from a body
The foot has many ancestors. The Romans used a pes of about 29.6 centimetres. In medieval Europe the foot varied from 25 to 35 centimetres by city and trade, and in England it was fixed by statute in the Middle Ages. The modern foot of 30.48 centimetres comes from the yard defined as 0.9144 metres in 1959. When you convert dm to ft, you bridge a revolution and a body part.
Altitude, aviation and the foot
Why pilots use feet
Aviation adopted the foot as the unit of altitude in the early twentieth century, when the leading aircraft makers were British and American. After the Second World War, the international civil aviation organisation made feet the standard for altitude, while distances are measured in nautical miles. Even Russia and China have partly adopted metric altitudes but most of the world still uses feet.
Typical altitudes
A small plane flies at 3,000 ft, which is 914 m or 9,144 dm. A helicopter hovers at 500 ft, 152 m. An airliner cruises at 35,000 ft, 10,668 m. A mountain such as Mont Blanc is 15,777 ft, 4,809 m. When a Dutch report gives an altitude in decimetres of 30,000, you will convert dm to ft for the pilot's chart.
Everyday objects in both units
The home
A standard door is 20 dm high, 6.56 ft. A kitchen counter is 9 dm, 2.95 ft. A bed is 20 dm long, 6.56 ft. A refrigerator is 18 dm high, 5.9 ft. Ceilings are commonly 25 dm, 8.2 ft.
The body
An adult is 16 to 19 dm tall, 5.2 to 6.2 ft. A baby at birth is 5 dm, 1.64 ft. An arm span roughly equals the height. A walking step is 7 dm, 2.3 ft.
Estimating on site
Using your own foot
An adult's shoe is about 2.8 to 3 decimetres long, so walking heel to toe gives a rough count of feet, and the count in decimetres is the same number multiplied by about 2.9. Mark the distance with a stake and check it against a tape. In the field, this method is accurate to within five per cent.
Combining with a tape
Many tapes show feet and metres on opposite edges. Check one edge against the other and note the offset, so you can convert dm to ft on the spot. Take two readings and average them.
Lumber and nominal sizes
Boards in feet
In the United States and Canada, lumber is sold in standard lengths of 6, 8, 10, 12 and 16 feet, which are 18.3, 24.4, 30.5, 36.6 and 48.8 decimetres. If a plan requires a board of 15 dm, the nearest standard board is 6 ft, with a little over to trim.
Cutting efficiently
Plan cuts to waste as little as possible. A 12-foot board, 36.6 dm, yields two pieces of 15 dm with 6.6 dm left over. Mark all cuts on a sketch, convert once and cut twice.
Reading a tape in feet and inches
The scale
American tapes show feet as large numbers every 12 inches, and inches subdivided into halves, quarters, eighths and sixteenths. A reading of 4 ft 11 1/16 in is 4.9193 ft. Keep a conversion card next to your tape.
Fractions of an inch
1/16 inch is 1.59 mm, 1/8 is 3.18 mm, 1/4 is 6.35 mm. The finest line on most tapes is 1/16. A plan in decimetres rarely demands more than a millimetre of precision, so round to the nearest 1/16 inch.
Money and materials
Estimating cost
Lumber is priced per foot or per board. If a board of 8 ft costs 12 dollars, a foot costs 1.50, and a decimetre 0.49. A plan requiring 60 dm of material needs 19.7 ft, about 30 dollars. Add 10 per cent for waste.
Shipping and storage
Long items such as rods or boards are charged by length. A package longer than 5 ft, 15.2 dm, may carry an oversize surcharge. Check carrier rules and plan the cut length so it fits the box.
A garden bench, worked through
The cut list in decimetres
Return to the Dutch bench plan. It calls for two legs of 4.5 dm, two rails of 12 dm, three slats of 15 dm and two arm rests of 6 dm. To convert dm to ft for the whole list, divide each figure by 3.048: the legs are 1.48 ft (1 ft 5.7 in), the rails 3.94 ft (3 ft 11.3 in), the slats 4.92 ft (4 ft 11 in) and the arm rests 1.97 ft (1 ft 11.6 in). Write the numbers on the plan next to the original ones, in a different colour, so that mistakes show up.
Buying the boards
The slats need 3 × 4.92 = 14.8 ft of board, the rails 7.9 ft, the legs 3 ft and the arm rests 3.9 ft. In total, about 29.6 ft, or just over 9 metres. Standard 8-foot boards can be cut into the pieces with little waste: one board gives a slat and a rail; three boards cover the slats, and so on. A lumber yard will usually cut to length, so bring the cut list in feet and inches.
Common questions from builders
Can I use a metric tape for the job?
Yes. A metric tape is often easier to use for a plan in decimetres, because you read centimetres directly. The only conversion left is the final order of material, where feet matter. Most American hardware shops will also sell boards by the metre in specialist ranges, but the standard lengths are in feet.
How accurate should I be?
For furniture, work to within 1 millimetre, or about 1/32 inch. For rough carpentry, such as a fence or a shed, a quarter inch is fine. Do not carry more digits than your saw can honour, but make sure that every part is converted from the original figure, not from a rounded intermediate result.
What if the plan mixes units?
Some imported plans mix decimetres for big parts and millimetres for thickness. Convert each class separately and keep a table. If you must convert dm to ft and then combine with a thickness in millimetres, convert everything to millimetres first, add, and convert the total at the end.
More values for convert dm to ft
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 dm = 0.0328084 ft
- 0.5 dm = 0.164042 ft
- 3 dm = 0.984252 ft
- 4 dm = 1.31234 ft
- 7 dm = 2.29659 ft
- 15 dm = 4.92126 ft
- 20 dm = 6.56168 ft
- 75 dm = 24.6063 ft
- 200 dm = 65.6168 ft
- 500 dm = 164.042 ft
- 2,000 dm = 656.168 ft
- 10,000 dm = 3,280.84 ft
Mistakes when you convert dm to ft
Using 3 instead of 3.048
A foot is not exactly three decimetres. On a long run, the difference adds up: 100 dm is 32.8 ft, not 33.3.
Confusing decimal feet with inches
0.5 ft is 6 inches, not 5. A result of 4.5 ft is 4 ft 6 in. Convert the decimal part to inches by multiplying by twelve.
Dividing the wrong way
Going from decimetres to feet gives a smaller number. If your result is larger than the input, you multiplied by 3.048 instead of dividing.
Quick answers
How many feet are in a decimetre?
0.328084.
How do I convert dm to ft?
Divide by 3.048, or multiply by 0.328084.
What is 10 dm in feet?
3.2808 ft, or 3 ft 3.4 in.
Is the conversion exact?
The relation is exact by definition; the decimals displayed are rounded.
Is my number sent anywhere?
No. Everything runs in your browser.
Related pages and a last word
If you work with lengths in both systems, these conversions are close by: Convert dm to km, Convert dm to in, Convert m to ft, Convert mi to ft, Convert ft to yd, Convert °C to °F, Convert °F to °C, Convert L to gal, Convert gal to L. The reverse of this page is Convert ft to dm.
In short, to convert dm to ft divide by 3.048, check that the answer is about a third of the starting figure and round to the precision your tape can read. Your number stays on your device: nothing is uploaded, and there is no account.