Feet and Inches Calculator

The imperial system of feet and inches is widely used in construction, architecture, and everyday life in the United States. But working with fractions and mixed numbers can be a real headache if we try to operate with imperial units of measurement. And that's where the foot and inch calculator saves us.

The Foot Calculator is an online tool that allows you to efficiently perform mathematical operations on measurements expressed in feet and inches. It works with whole numbers, fractions, and mixed numbers. The foot and inch calculator can add, subtract, multiply, and divide values in imperial units.

Using a feet calculator can save you time and hassle when working with imperial measurements. It eliminates the need for manual calculations that are time-consuming and can be fraught with errors. With a foot and inch calculator, you can ensure the accuracy of your calculations. It will help you avoid costly mistakes in construction, architecture and other fields.

Manual Imperial Units Calculations

Of course, this measurement calculator processes the numbers in less than a second. But you can perform manual operations with imperial units if you want more control over the process.

Unlike the metric system, imperial units do not use the tens-based system, which makes calculations a bit more complicated. To add and subtract imperial units, it is very important to know the conversion factor for each unit. For example, in the case of feet and inches we should always remember that one foot equals 12 inches.

Conversion method

One method recommends converting all the units to one unit (foot or inch) and calculating in that unit. And then, if you need, you can convert the result to another convenient form.

Adding Feet and Inches

Adding manually feet and inches may look cumbersome from the beginning. But if you try doing this several times you will get more skilled in performing this operation.

For example, you need to add up 2 feet and 8 ½ inches and 2 feet 5 ¾ inches.

Calculating in inches

We convert them to inches.

(2 × 12) + 8 + ½ = 24 + 8 ½ = 32 ½ inches for the first number

and

(2 × 12) + 5 ¾ = 24 + 5 ¾ = 29 ¾ for the second number

Then we add up the results of the conversion. Add inches to inches:

32 ½ + 29 ¾ = 32 2/4 + 29 ¾ = 61 + 5/4 = 61 + 1 ¼ = 62 ¼

And after that, we convert the result to feet.

62 ¼ / 12 = (5 × 12) + 2 + ¼ = 5 feet and 2 ¼ inch

Thus, we end up with the final result of adding inches:

2 ‘ 8 ½’’ + 2 ‘ 5 ¾’’ = 5’ 2 ¼’’

Calculating in feet

Or you can convert units into feet and perform operations with feet:

2 feet and 8 ½ inches and 2 feet 5 ¾ inches = (2 + 8.5/12) feet + (2 + 5.75/12) feet = 2.7083 feet + 2.4792 feet = 5.1875 feet

We can perform this procedure using addition, subtraction, multiplication, or division.

Check this math in a feet and inches calculator and you will get the same results.

Subtracting Feet and Inches

Calculating in inches

We count with conversion to inches:

5 feet 2 ¾ inches – 3 feet 9 ½ inches = 62 inches ¾ – 45 2/4 inches = 17 ¼ inches = 1 foot 5 ¼ inches

Calculating in feet

And we count with conversion to feet:

5 feet 2 ¾ inches – 3 feet 9 ½ inches = 5.2292 feet – 3.7917 feet = 1.4375 feet

Multiplying Feet and Inches

Calculating in inches

Here we can calculate using inch conversion first:

5 feet 2 ¾ inches × 3 feet 9 ½ inches = 62.75 inches × 45.5 inches = 2855.125 inches²

But in this case, we have square units. So, we divide the result not by 12 but by 144 to get feet.

2790 / 144 = 19.8273 feet²

5.1667 feet × 3.75 feet = 19.8273 feet²

Calculating in feet

And we can calculate with conversion to feet from the beginning:

5 feet 2 ¾ inches × 3 feet 9 ½ inches = 5.229167 feet × 3.791667 feet = 19.82726 feet²

Dividing Feet and Inches

Calculating in inches

Here we can start again from converting to inches:

5 feet 2 ¾ inches / 3 feet 9 ½ inches = 62.75 inches / 45.5 inches = 1.3791

Calculating in feet

Or we can manipulate with feet from the first step:

5 feet 2 ¾ inches / 3 feet 9 ½ inches = 5.229167 feet / 3.791667 feet = 1.3791

Calculation Without Unit Conversion

Using the second method of calculating the units without converting to feet or inches, we add the numbers directly in feet and inches. We start from right to left from lesser values to greater values, and transfer the values if the result of adding inches is greater than 12. Or if the fractional part becomes bigger than 1.

Addition

In the example with our numbers, the calculation would go like this:

5 feet 2 ¾ inches + 3 feet 9 ½ inches

The first step – adding fractions:

¾ + ½ = ¾ + 2/4 = 5/4 = 1 ¼

So, we can move one whole inch to the next level.

The second step – adding inches.

2 inches + 9 inches = 11

Plus 1 ¼ from the previous step and we get 12 ¼

So, we have 1 whole foot and ¼ inches as the result and we move this new foot to the next level.

The third step is adding feet:

5 + 3 feet = 8

plus we add another 1 foot that we got when we added up the inches and get 9 total inches

Then we write down the results from all 3 steps:

9 feet ¼ inches

Subtraction

Let's make the subtraction with the numbers that we already used in this article:

5 feet 2 ¾ inches – 3 feet 9 ½ inches

We start from the smallest units – fractions.

¾ - ½ = ¾ - 2/4 = ¼

The second step – subtracting inches. We can't subtract 9 from 2. So we borrow one unit (12 inches) from 5 feet. 2 inches + 12 inches = 14 inches.

14 inches – 9 inches = 5 inches

The third step is subtracting feet. Now we have not 5 but 4 feet as the result of borrowing. So, we subtract:

4 feet – 3 feet = 1 foot

And we write down the total result:

5 feet 2 ¾ inches – 3 feet 9 ½ inches = 1 foot 5 ¼ inches

To multiply and divide feet and inches, it is highly recommended that you use the conversion method. That is, convert your values to feet and inches only and perform the calculations in one unit of measurement. You can choose to convert to feet or inches, whichever is more convenient for you.

Measurements Based on Human Body in History

In the history of human measurement there have been many units based on parts of the human body. This is not surprising. A tool like an arm or a leg is always with a person. It is as hard to lose as a ruler, tape measure, or other measuring instrument. Let's look at how our predecessors used their body parts to measure objects throughout the ages.

Finger

The finger is an ancient unit of measurement that has been used in various cultures, including Ancient Egypt, Mesopotamia, Greece, and Rome, throughout history. It is based on the width of a human finger and has fallen out of use in modern times, except for some informal usage in specific fields.

In Ancient Egypt, the finger was a basic subdivision of the cubit and was about 19 mm.

In modern usage, the finger is usually defined as 3/4 of an inch or 1/16 of a foot, approximately 1.905 cm.

In English, the term "finger" is still used informally in medicine and related disciplines as a unit of measurement and also in the measurement of distilled spirits. A "finger of whiskey" refers to the amount of whiskey that would fill a glass to the level of one finger wrapped around the glass at the bottom.

Palm

The term "palm" can refer to two different units of measurement, one based on the width of the human palm and the other based on the length.

The palm's width has been used in Ancient Egypt, Israel, Greece, and Rome, as well as in medieval England, where it was also known as the handsbreadth. In Ancient Egypt, the palm was known as the shesep, typically around 75mm or 3 inches in length. The palm was further divided into four fingers, about 19mm or 0.75 inches.

The length of the hand, also known as the Roman "greater palm," was used in medieval Italy and France. In Spanish and Portuguese, the palm was known as the "palmo menor" and "palmo de craveira," respectively.

In ancient Israel, the palm was known as the tefah, tepah, or topah. The palm was divided into four digits.

In Ancient Greece, the palm was known as the "palaistē," "dōron," or "daktylodókhmē." It made up ¼ of the Greek foot, which varied by region between 27-35cm. This gives values for the palm between 6.7-8.8cm, with the Attic palm around 7.4cm.

Hand

The standard unit of measurement as an arm is about 4 inches (101.6 mm). The hand is commonly used to measure the height of horses in many English-speaking countries, including the United States, Great Britain, Australia, and Canada. It was originally based on the width of a human hand.

In the United Kingdom, hand size was standardized at four inches by statute of King Henry VIII in 1540. However, confusion between the different types of hand measurements persisted, and different values were assigned to the hand and hand width. The adoption of the international inch in 1959 standardized the imperial form of this unit.

This unit is unique in that it uses a division system based on the base of 4, so measurements are expressed in quarters of the hand, which are equal to inches.

Cubit

Сubit is an ancient measurement of length. It was mainly used by the Sumerians, Egyptians, and Israelites. The cubit is mentioned in the Bible in connection with such structures as Noah's Ark, the Ark of the Covenant, and Solomon's Temple. The ancient Egyptians used the royal cubit as the earliest known standard measure. Cubits were used to measure length, and many of the cubit measuring rods have been found in the tombs of the 18th dynasty Pharaoh Tutankhamun.

The cubit was also used in a biblical context. It was used to measure structures, including Solomon's temple.

The term "cubitum" comes from the Latin noun "cubitum," meaning elbow. A cubit is equal to the distance that can be measured from the tip of the middle finger to the elbow.

In some cases cubitum was equal to 6 palms or 24 fingers. The king's cubit, used by the ancient Egyptians, was divided into 7 palms × 4 fingers, that is, 28 fingers. This length usually ranged from 44.4 to 52.92 cm. And the length of the ancient Roman cubit was 120 cm (3 feet 11 inches).

Shaftment

A shaftment is an ancient unit of measurement that was widely used in medieval England. It was defined as 6 inches, which is exactly 152.4 millimeters in modern measurements. The unit was based on the width of the fist and outstretched thumb, making it easy to measure the lengths of poles, staves, and other objects by grasping the bottom of the staff and repeating hand-over-hand grips along the length of the staff.

The shaftment was mentioned first time in Anglo-Saxon records as in 910. With the introduction of the modern foot in the 12th century, the shaftment was redefined as exactly half a foot, or 6 inches. It was also spelled as "schaftmond", "scaeftemunde," and "shathmont." The name of the unit came from Old English "sceaft," which means "hand."

Foot

The foot, represented by the symbol "ft", is a unit of length that is commonly used in both the British imperial and United States customary systems of measurement. Historically, the foot was based on the length of the human foot. The length of one foot is officially defined as 0.3048 meters, and it is further divided into 12 inches.

The foot has been used as a unit of measurement for a very long time, extending back to such civilizations of the ancient world as Egypt, Greece, and Rome. The length of the foot varied depending on the location and era, but it was typically between 250 mm and 335 mm. It was generally divided into 12 inches.

The United States is the only one industrialized economy that still uses the international foot and the survey foot instead of the meter in its business, engineering, and standards work.

The foot is a legal unit of length in the United Kingdom, and most people there use it to measure their height.

Ell

An ell is an obsolete unit of measurement that originated in northwestern Europe. The word "ell" literally means "arm" and is thought to have been based on the combined length of a person's forearm and extended hand. Historically, different forms of the ell existed in various countries, including the Scottish ell (approximately 37 inches or 94 centimeters), the Flemish ell (approximately 27 inches or 68.6 centimeters), and the French ell (approximately 54 inches or 137.2 centimeters).

The ell-wand or ellwand was a rod of one ell in length used for official measurements. The King Edward I required that every town have one in England. Rural churches were also responsible for disseminating uniform measures, as evidenced by the iron ellwand preserved in the entrance of Stånga Church on the Swedish island of Gotland.

In England, the ell was usually exactly 45 inches (1.143 meters) long, which is the same as a yard and a quarter. It was mostly used in the tailoring business, but no one uses it anymore. In 1661, the Scottish ell became a standard unit of measurement. But in 1824, an act of parliament called the Weights and Measures Act made English measurements the standard in Scotland. This meant that Scottish measures were no longer used.

Fathom

A fathom is used to measure the depth of water. It is commonly used in the maritime industry to measure the depth of water in ships and boats. It is also used in underwater diving to measure the depth of the dive.

One fathom is 6 feet or 1.8288 meters.

The word fathom comes from the Old English word faeðm, which means a pair of arms that are stretched out. At first the fathom was equal to the length of a man's outstretched arms. Over time the size changed slightly depending on whether the fathom was based on the admiralty nautical mile or the imperial yard.

In the British Admiralty, a fathom was defined as a thousandth of an imperial nautical mile (6080 ft) or 6.08 feet (1.85 m). In practice, the "warship fathom" of exactly 6 feet (1.8 m) was used in Britain and the United States.

Smoot

Smoot is an unofficial unit of measurement first used in the 1950s by Oliver Smoot, a student of MIT - the Massachusetts Institute of Technology. This unit, equal to 5 feet 7 inches (1.7 meters), was originally used to measure the length of the Harvard Bridge connecting Boston and Cambridge, Massachusetts.

Smoot became interested in measuring the bridge after he was elected to the Lambda Chi Alpha fraternity, where there was a tradition of measuring the bridge. He used his own body as a measuring tool, laying down on the bridge and marking the distance in increments of his own body length.

Using Smoot as a measurement unit caught the media's attention, and it quickly became an interesting and humorous way to measure bridge length. The unit has since been used in various contexts, such as to measure the length of marathon races, the height of buildings, and even the distance between planets.