Feet and Inches Calculator

Add, subtract, multiply, or divide feet-and-inches measurements and convert the result to decimal feet, inches, centimetres, and metres.

Measurement A

Operation

Measurement B

Best fit

Use this tool when you need feet-and-inches arithmetic first and metric output second, such as layout changes, equal cuts, or field-to-plan checks.

Result

7 ft 9 in

Combined run length in imperial and metric formats.

Total inches
93
Decimal feet
7.75
Centimetres
236.22
Metres
2.36

Working note

The calculator converts compound feet-and-inches entries into total inches first, then rebuilds the result in imperial and metric formats to avoid carrying mistakes.

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Feet & Inches

Feet and inches calculator: imperial length arithmetic with decimal feet and metric output

A feet and inches calculator helps when the measurement itself is already in compound imperial notation and the next task is arithmetic, not just unit conversion. That is common in joinery, layout, field measurement, and renovation work where lengths are written as feet plus inches and still need to be added, subtracted, multiplied, or divided.

Why compound imperial lengths are awkward by hand

Feet-and-inches notation is easy to read on tape measures and plans, but it is slower to manipulate mentally because inches have to be carried into feet every time they cross 12. That makes simple arithmetic error-prone, especially when several lengths are combined or when one total run is split into equal parts.

A dedicated calculator removes that carry problem by translating each measurement into total inches first, doing the arithmetic there, and then rebuilding the result as feet and inches. That keeps the familiar imperial format while still exposing the decimal-foot and metric equivalents for the next workflow.

The working method behind the result

The underlying method is straightforward. First convert the entered feet-and-inches measurement into total inches. Then apply the chosen arithmetic operation. Finally, split the result back into whole feet plus the remaining inches and derive decimal feet, centimetres, and metres from the same base length.

Because the metric outputs come from the same computed total inches, the imperial and metric views stay aligned. That is useful when a job starts in feet and inches but the purchased materials, supplier sheets, or design software use metric length notation.

Total inches = (feet × 12) + inches

Base conversion used before any arithmetic is applied.

Decimal feet = total inches ÷ 12

Simplified imperial output for estimating, pricing, and software entry.

Metres = total inches × 0.0254

Exact international-inch relationship used for metric output.

When decimal feet or centimetres are more useful than compound notation

Compound feet-and-inches output is best when you are reading directly from a tape or keeping the result in an imperial build workflow. Decimal feet are often easier for quoting, take-offs, and spreadsheet work, while centimetres and metres are more useful when a project crosses into metric product specs or drawings.

That is why the live tool shows all of those formats at once. It lets the same computed length stay readable in the notation the next person or system actually expects, without making you recalculate from scratch.

Frequently asked questions

How do I add feet and inches correctly?

Convert both measurements into total inches, add them, and then carry one foot for every 12 inches in the result. This calculator performs that carry automatically and also shows the decimal-foot and metric equivalents.

 Can I divide a length into equal sections?

Yes. Enter the total length as measurement A, switch to divide mode, and use the divisor input for the number of equal parts. The tool returns each section in feet and inches as well as decimal feet and metric output.

 Why show decimal feet as well as feet and inches?

Because many estimating sheets, quotes, and software tools accept decimal feet more easily than compound notation. Both values describe the same length; they are just written differently.

 Can the result be negative?

Yes, if you subtract a larger measurement from a smaller one. The calculator keeps the sign visible so you can spot that the arithmetic direction produced a deficit rather than an added run length.

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