Feet and Inches to Calculator: Convert to Decimal Feet

A feet-and-inches calculator converts a measurement such as 5 ft 8 in into decimal feet, total inches, or metric units. Enter the number of feet and inches separately; the calculator below returns the combined length in decimal feet and total inches.

Formula

First convert the inches to a fraction of a foot, then add that fraction to the feet:

Decimal feet = feet + inches ÷ 12

To express the same measurement in total inches, use Total inches = (feet × 12) + inches. To convert total inches to meters, multiply by 0.0254.

• Feet is the whole number of feet entered, in ft.
• Inches is the remaining length, in in. The calculator accepts values from 0 to just under 12 inches.
• Decimal feet is the combined length in feet, rounded to three decimal places.
• Total inches is the combined length in inches, shown to two decimal places.
• Length is the metric equivalent in meters, rounded to three decimal places.

There are 12 inches in one foot, and one inch is exactly 0.0254 meters. Decimal feet are not decimal inches: for example, 5.5 ft means 5 feet plus half a foot, or 5 ft 6 in.

Worked Example

Using the calculator’s defaults, enter 5 feet and 8 inches.

1. Convert the inches to feet: 8 ÷ 12 = 0.666666… ft.
2. Add the feet: 5 + 0.666666… = 5.666666… ft, which rounds to 5.667 ft.
3. Convert to total inches: (5 × 12) + 8 = 68 in.
4. Convert total inches to meters: 68 × 0.0254 = 1.7272 m, which rounds to 1.727 m.

The results describe one length in three unit formats: 5 ft 8 in, 5.667 decimal feet, 68 inches, or 1.727 meters when rounded to the displayed precision.

How to Convert Feet and Inches

Feet-and-inches notation combines a whole-foot count with a remaining inch count. It is commonly used for dimensions and everyday measurements in places where US customary units are familiar. The conversion is arithmetic, not a change in the actual length.

For a manual conversion, multiply the feet by 12 and add the inches to get total inches. Divide the inches by 12 and add that fraction to the feet to get decimal feet. For example, 3 ft 9 in is 45 total inches, or 3.75 ft, because 9 ÷ 12 = 0.75.

To switch from decimal feet back to feet and inches, take the whole-number feet first. Multiply the decimal remainder by 12 to find the inches. For instance, 6.25 ft is 6 ft plus 0.25 × 12 = 3 in, so it is 6 ft 3 in.

When Decimal Feet Are Useful

Decimal feet are convenient when a calculation expects a single numeric length rather than separate feet and inches. They can be used in spreadsheets, area calculations, or when comparing measurements in one consistent format. Total inches may be easier for small dimensions, while meters are useful when working with metric specifications.

Choose the format that matches the next calculation. If multiplying a length by a width to find an area, convert both dimensions to the same unit first. A value in feet multiplied by a value in inches does not directly produce square feet or square inches without an additional conversion.

Common Conversion Mistakes

• Writing inches as a decimal part of a foot: 5 ft 8 in is not 5.8 ft. Eight inches is 8 ÷ 12 = 0.6667 ft, so the decimal form is about 5.667 ft.
• Confusing decimal feet with feet-and-inches notation: 5.8 ft means 5 feet plus 0.8 foot, and 0.8 × 12 = 9.6 inches. It does not mean 5 ft 8 in.
• Entering 12 or more inches as the remainder: Normalize the measurement first. For example, 4 ft 14 in is equivalent to 5 ft 2 in.
• Rounding too early: Keep the full value during intermediate steps and round only the final display. Rounding decimal feet early can introduce a small difference when converting again.
• Mixing units in a formula: Convert every input to the same unit before adding, subtracting, multiplying, or comparing lengths.

Precision and Limits

The calculator shows rounded results, but the underlying conversions use the entered values and exact conversion factors. A displayed 5.667 ft is a rounded representation of 5.666666… ft; converting the rounded value back may therefore produce a slight difference. For work requiring a specified tolerance, retain more precision in the calculation and follow the measurement or project’s stated rounding rules.

The calculation assumes that the input represents a length and that the inches are a remainder from 0 up to, but not including, 12. It does not assess measurement accuracy, account for instrument error, or decide whether a particular rounding convention is appropriate. If inches are entered as a decimal, such as 8.5, the arithmetic still works: 8.5 inches is eight and a half inches.

Frequently Asked Questions

How many inches are in a foot?
One foot equals 12 inches. Therefore, multiply a number of feet by 12 to express it in inches.

How do I convert 5 feet 8 inches to decimal feet?
Divide 8 by 12, then add 5: 5 + 8 ÷ 12 = 5.666666…, or 5.667 ft rounded to three decimal places.

Is 5.8 feet the same as 5 feet 8 inches?
No. 5.8 ft equals 5 ft 9.6 in, because 0.8 ft × 12 = 9.6 in. Five feet 8 inches is about 5.667 ft.

How do I convert decimal feet into inches?
Multiply decimal feet by 12. For example, 5.5 ft × 12 = 66 in. To write that as feet and inches, divide 66 by 12: 5 ft 6 in.

How do I convert feet and inches to meters?
Convert the measurement to total inches, then multiply by 0.0254. For 5 ft 8 in, the total is 68 inches, which equals 1.7272 meters.

Related

• Convert ft to m Calculator: Formula and Examples
• Convert Millimeters to Centimeters: Formula and Examples
• m/s to km/h Conversion Formula and Calculator

in ft | Feet | ft | 5 | 0
in inch | Inches | in | 8 | 0 | 11.999999
out decft | Decimal feet | ft | ft + inch / 12 | 3
out totalin | Total inches | in | ft * 12 + inch | 2
out meters | Length | m | (ft * 12 + inch) * 0.0254 | 3