Inch is the standard unit in the imperial system of measurement. To calculate values of type, we usually use a ruler or measuring tape. In addition, there are also ways to determine the number of inches with estimates and conversions. Although the metric system prevails in Brazil, it may still be useful to know the relationship between inches and other units.

## Steps

### Method 1 of 4: Measure in inches with a ruler or measuring tape

#### Step 1. Choose the best tool to take the measurement

The most common options are rulers and measuring tapes - and they should have inch markings.

- Use a long ruler when you want to measure part of a line or rigid surface, a shorter ruler for short distances, and so on.
- Use a measuring tape when you need to measure a curved object. These accessories are malleable, making them ideal for surfaces that aren't straight.

#### Step 2. Align the fixture tip marked 0 with one end of the surface being measured

Both should be snug.

- If the starting tip of the accessory is not marked with a "0", use it from the number "1", which comes right after.

#### Step 3. Extend the fixture across the surface being measured

Make them completely parallel.

- If using a ruler, it should be quite parallel to the edge of the surface or line being measured.
- If using a measuring tape, it should span the entire distance from the surface being measured.

#### Step 4. View the previous value in inches

On the fixture, find the number just before the opposite end of the line, end, or distance being measured. This value will represent the extent of the object.

- The numbered values of rulers, measuring tapes and the like correspond to the exact inches (or centimeters, depending on the accessory) - provided the accessory in question has this type of unit, obviously.
- The lines between the numbers represent fractions of inches.

#### Step 5. Count the unnumbered lines after the last inch

Identify the line that lies exactly on the edge of the distance or object you are measuring. Count how many there are between the nearest inch and the end line (including it).

- You will also have to count the number of unnumbered lines between the numbered values to determine the fraction.
- If there is an unnumbered line, the inches will be halved.
- If there are three unnumbered lines, the inches are divided by 1/4.
- If there are seven lines without numbers, the inches are divided by 1/8.
- If there are 15 lines with no numbers, the inches are divided by 1/16.

#### Step 6. Add the fraction you just counted to the total value in inches (already measured)

This will generate the final measurement.

- Example: If there are seven unnumbered lines between the numbered parts, the inches will be divided by 1/8. The extension from the 0 to the fifth unnumbered row after the 3 mark will be 3 inches + 5/8 inches - or 3 5/8.
- If the tip of the accessory rests on a numbered line, you don't need to add fractions to it.
### Example: If the line runs from the end of the 0 to the 6 mark, it will be 6 inches long

### Method 2 of 4: Estimate Inches

#### Step 1. Find an object that is about an inch long

The thumb is the most common object for this type of estimate - hence the name of the unit - and it has the right measurement.

- The distance between the joint and the tip of the thumb of an adult hand is about an inch.
- Other options might include a water bottle cap, a regular eraser or pencil eraser, a paper clip, and a small sewing pin.

#### Step 2. Using a pencil, outline the extent of the object to be measured on a sheet of paper

Start at one end and end at the other.

- The line outlined on the paper must be the exact same length as the object you want to measure. After going around it, remove the object from the paper.
- Use a sheet of white or other light-colored paper so you can see the pencil marks.

#### Step 3. Place the one-inch object at the beginning of the line

Line up both and mark the other end of the item with the pencil.

- For example, if you are using the widest part of an eraser to estimate inches, put it on the paper, parallel to the line. One of its longest sides must be perpendicular to the beginning of the marking. The other must be perpendicular to the line itself, at one of its points. Use the pencil to mark the final position of this second side.

#### Step 4. Take the one-inch object to the other side of the line

Thus, it will be over the mark made earlier. As before, make another mark on the second end of the item.

- Continue along the line until you reach the tip.
- Every time you change the position of the measurement object, make sure the structures are parallel.

#### Step 5. Add spaces

After reaching the end of the line, remove the measurement object. Count the number of spans between each marking. This number will be a rough estimate of inches.

- Count the spaces between the lines - not the lines themselves.
- Also count the spaces before the first line and after the last.
- If the space after the last line is much smaller than the rest, look at it with your eyes to see what you will need to add to your estimate. For example, if it is half as wide as the others, count it as half an inch.

### Method 3 of 4: Convert other imperial measurements to inches

#### Step 1. Convert feet to inches

One foot equals 12 inches. To convert a measure with these units, simply multiply the feet value by 12.

- Example: 5, 2 feet * 12 = 62, 4 inches.

#### Step 2. Calculate the number of inches from the number of yards

One yard equals 36 inches. To convert a measure with these units, multiply the yardage value by 36.

- Example: 2, 76 yards * 36 = 99, 36 inches.

#### Step 3. Find the number of inches from a number of miles

One mile equals 63,360 inches. To convert a distance measurement with these units, multiply the mile value by 63,360.

- Example: 0.49 miles * 63,360 = 31,046, 4 inches.

### Method 4 of 4: Convert metric measurements to inches

#### Step 1. Calculate inches from a millimeter value

Multiply this value by 0.03937 - the inches relative to a single millimeter - to perform the conversion.

- Example: 92, 6mm * 0.03937 = 3.65 inches.

#### Step 2. Convert centimeters to inches

Each centimeter equals 0.3937 inches. To perform the conversion and find a measured distance in cm, multiply the value by 0.3937.

- Example: 34, 18 centimeters * 0, 3937 = 13, 46 inches.

#### Step 3. Determine inches from a number of meters

Each meter equals 39.37 inches. If you want to convert, multiply the desired value by 39, 37.

- Example: 7, 03 meters * 39, 37 = 276, 77 inches.