The imperial calculator will be helpful whether you just need to recall a conversion factor or you never use imperial units and you never remember how many feet are in a yard (and everything else!).

Keep reading to learn:

  • A (very) short history of the imperial units of measurement;
  • How to calculate and convert imperial units of measurement;
  • Calculate the imperial units' conversion in length, area, temperature, and much more;
  • How to read the imperial units table for the most common imperial units of measurement.

How to convert imperial units

There is no unique rule to convert between imperial units: unlike the metric system, where a division or multiplication by 1010 can bring you wherever you need, imperial units follow varying relationships, with ratios between multiples and submultiples often changing.

There's no solution or shortcut: you must remember all the conversions or use a tool to help you with that! In the following sections, you will learn how to do so for the most commonly measured quantities.

Calculate imperial units of measurements conversions for the most common quantities

Converting imperial units of measurement for length

In the imperial system, we measure length using an assortment of units: inches, feet, yards, and meters. The "base" unit, the most commonly used, is the foot. Why foot? Because in the past, to define this unit, the body part of kings and rulers were used as standards! Feet are great for measuring "human-sized" objects. If you need to measure smaller objects, go for inches; for bigger things, use yards and miles. The relationships between these units are:

1 ft=12 in1 ft=13 yd1 ft=15280 mi\begin{split} 1\ \mathrm{ft} &= 12\ \mathrm{in}\\ 1\ \mathrm{ft} & = \frac{1}{3}\ \mathrm{yd}\\ 1\ \mathrm{ft} & = \frac{1}{5280}\ \mathrm{mi} \end{split}

It may be helpful to know some of the inverse conversions:

1 yd=3 ft=36 in1\ \mathrm{yd} = 3\ \mathrm{ft} = 36\ \mathrm{in}

Converting imperial area units of measurement

To convert area imperial measurement units, simply take the square of the conversion factors for length. For example:

1 ft2=144 in21\ \mathrm{ft^2} = 144\ \mathrm{in^2}

Converting imperial volume units

You know how it works now! If we had to consider a square to learn the units for area, to find the units for the volume, we would have to calculate the cube of the length's conversion factor. The previous conversion becomes:

1 ft3=1728 in31\ \mathrm{ft^3} = 1728\ \mathrm{in^3}

How to calculate and convert imperial units for weight

The most commonly used unit for weight in the imperial system is the pound. A pound is great for measuring your weight or the weight of an object you can lift with minimal effort. If you don't even feel the weight, you should use the ounces (oz\mathrm{oz}). For objects you can't lift unless you are a superhuman, you should use the ton. Here are the conversion factors:

1 lb=16 oz1 US ton=2000 lb\begin{split} 1\ \mathrm{lb}&=16\ \mathrm{oz}\\ 1\ \mathrm{US\ ton}& = 2000\ \mathrm{lb} \end{split}

Temperature conversion in the imperial system

There are only two temperature units in the imperial system: the Fahrenheit and the Rankine. The first one is perfect for measuring the temperature of the day; the other can be used by scientists, as it assigns the zero point to the absolute zero. We convert between these two units with a simple sum/subtraction:

T°R=(T°R459.67)°FT_\mathrm{\degree R} = (T_\mathrm{\degree R} − 459.67)_{\mathrm{\degree F}}

Table of the imperial units of measurements

You can use our imperial calculator to convert between units! However, if you want to do these operations on your own, here is a collection of tables to sum up the conversions we detailed above.

Length conversion





















Weight conversion













More than calculating imperial conversion: other measurement conversion tools


How do I calculate and convert imperial units for length, area, and volume?

To calculate the conversion of imperial units for length, area and volume, follow these simple steps:

  1. Remember the conversion of imperial units for the length:
    • 1 mi = 1,760 yd
    • 1 yd = 3 ft;
    • 1 ft = 12 in
  2. To convert between surface imperial measurement units, use the square of the corresponding conversion factors for length (for example, 1 ft² = 144 in²).
  3. The conversion of volume imperial measurement units uses the cube of the conversion factors for the length (that is, 1 ft³ = 1,728 in³).

How much is 10 inches in feet?

10 inches is 0.8333 feet. To find this result, follow these easy steps:

  1. Find the conversion between inches and feet:
    1 in = 0.08333 ft
  2. Multiply the conversion factor by the quantity you need to convert:
    10 in = 10 × 0.08333 ft = 0.8333 ft

That's it!

How do I convert cubic feet to gallons?

Gallons and cubic feet are both units of volume in the imperial system. To convert between them, use the following conversion:
1 ft³ = 7.48 gal
The inverse conversion is:
1 gal = 0.13368 ft³
This conversion can help you switch from cubic feet, inches, and yards to gallons, pints, and cups.

How do I convert imperial units?

To convert imperial units, you need to learn the conversion factors between them. Here are some of them:

  • Length: 1 yd = 3 ft and 1 ft = 12 in;
  • Area: 1 yd² = 9 ft² and 1 ft² = 144 in²;
  • Volume: 1 yd³ = 27 ft³ and 1 ft³ = 1728 in³;
  • Weight: 1 lb = 16 oz and 1 ton = 2000 lb.

By multiplying conversion factors, you can find how to pass from any units associated with the same quantity.

Davide Borchia
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