Formula
Total inches = feet × 12 + inches + eighths ÷ 8. Decimal feet = total inches ÷ 12. Centimetres = total inches × 2.54. Metres = centimetres ÷ 100. Planning decimal feet = (total inches + allowance inches) ÷ 12.
Feet and Inches to Decimal Feet Calculator
Convert feet and inches to decimal feet for cut lists, room measurements, estimating sheets and classroom work, with metric cross-checks and a printable measurement record.
Worked example
For 5 ft 8 in with 0 extra eighths, total inches = 5 × 12 + 8 = 68 in. Decimal feet = 68 ÷ 12 = 5.6667 ft. The metric cross-check is 68 × 2.54 = 172.72 cm, or 1.7272 m.
Professional note
Master’s Tip: print both the tape-measure form and the decimal-foot result. Estimating sheets often want decimal feet, while site notes and cut lists are easier to check in feet and inches.
Regional and unit assumptions
Standard or basis: international foot and inch, with 1 foot = 12 inches and 1 inch = exactly 2.54 centimetres. This is a measurement, estimating and worksheet calculator, not a fabrication tolerance certificate or engineering approval.
Assumptions and limitations
- Feet and inches are treated as international-foot and international-inch measurements.
- Extra eighths are added to the inch field before conversion, so 5 ft 8 in and 4 eighths becomes 5 ft 8.5 in.
- Inch values over 12 are accepted because the formula uses total inches; the result still reports one decimal-foot total.
- Cut or clearance allowance is shown separately from the measured conversion so the original measurement remains auditable.
- For structural drawings, code work, fabrication tolerances or supplier orders, confirm the required unit, rounding rule and site measurement before relying on the number.
Methodology & Accuracy
How this calculator is checked
CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.
Formula used
Total inches = feet × 12 + inches + eighths ÷ 8. Decimal feet = total inches ÷ 12. Centimetres = total inches × 2.54. Metres = centimetres ÷ 100. Planning decimal feet = (total inches + allowance inches) ÷ 12.
Standard or basis
Standard or basis: international foot and inch, with 1 foot = 12 inches and 1 inch = exactly 2.54 centimetres. This is a measurement, estimating and worksheet calculator, not a fabrication tolerance certificate or engineering approval.
Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.Master's Tip
Master’s Tip: print both the tape-measure form and the decimal-foot result. Estimating sheets often want decimal feet, while site notes and cut lists are easier to check in feet and inches.
Related calculators
Questions
How do I convert feet and inches to decimal feet?
Multiply feet by 12, add the inches, then divide total inches by 12. For example, 5 ft 8 in is 68 inches, and 68 ÷ 12 = 5.6667 ft.
What is 5 feet 8 inches in decimal feet?
5 feet 8 inches is 5.6667 decimal feet before rounding because 5 × 12 + 8 = 68 inches and 68 ÷ 12 = 5.6667.
Can I include eighths of an inch?
Yes. Enter the whole inches and then the extra eighths. The calculator adds eighths ÷ 8 to the inch measurement before converting to decimal feet.
Why keep allowance separate from the decimal-feet conversion?
Allowance is a job or cutting decision, not part of the measured value. Keeping it separate makes the printout easier to audit later.
What should I print for a decimal-feet measurement record?
Print the feet, inches, fraction, total inches, decimal feet, metric cross-checks, rounding basis, allowance, formula, date, page URL and job notes.
Calculation note
Feet-and-inches notation is natural on a tape measure, but spreadsheets, estimating software and some formulas often need one decimal-foot number. A good record keeps both forms visible.
Decimal feet are a bridge format
A worker may measure 5 ft 8 in on site, while a spreadsheet column expects 5.6667 ft. The conversion is simple, but the paper trail matters when the number feeds area, volume or cost calculations.
Fractions belong before rounding
Tape-measure fractions such as eighths should be converted into inches before the decimal-foot division. Rounding the final decimal too early can change downstream material estimates.
Allowances should stay visible
Clearance, saw kerf, waste and tolerance decisions are not unit conversions. Showing them as separate report lines protects the original measurement and makes job notes easier to review.