TEBAMI
Choose the tool for the measurement
Use Add/Subtract Measurements to combine lengths. Use Feet/Inches ↔ Metric to change unit systems, or Feet/Inches ↔ Decimal Feet to express a tape measurement as decimal feet. These tools are useful when a plan uses metres but the available stock or tape uses feet and inches.
How do you combine feet and inches?
Total inches = feet × 12 + inches, including any fractional inch. Decimal feet = total inches ÷ 12. Millimetres = total inches × 25.4.
5 ft 7 3/8 in
5 × 12 + 7 + 3/8 = 67.375 in.
67.375 × 25.4 = 1711.325 mm.
67.375 ÷ 12 ≈ 5.6145833333 ft.
5 ft 7 in is not 5.7 ft: 0.7 ft means 8.4 in. Keep the feet and inches separate until you deliberately convert them.
A practical subtraction
Suppose a 5 ft 7 3/8 in length needs a 22 3/4 in piece removed, before allowing for any saw cut.
67.375 in − 22.75 in = 44.625 in.
That is 3 ft 8 5/8 in, or 1133.475 mm.
This arithmetic does not automatically subtract kerf, trim or fitting clearance. Add those explicitly if the job requires them.
Use the Free tools in Tebami
- Open Feet/Inches ↔ Metric, select From ft and To mm, and enter 5 ft 7 3/8 in.
- Tap Calculate. The displayed metric result may be rounded; use the calculation details and your required precision.
- For the subtraction, open Add/Subtract Measurements and enter 5 ft 7 3/8 in - 22 3/4 in. Select in for the result and tap Calculate.
In Add/Subtract Measurements, include a unit on each measurement. In a converter, an unlabelled value uses its selected From unit. Explicit units make mixed-unit expressions easier to check.
Units and precision
The international inch is exactly 25.4 mm and the foot is exactly 0.3048 m. The conversion factor is exact; a measured input and its displayed rounded result may not be. Fractional output marked ≈ is an approximation at the selected precision.
Reference: NIST: SI units — length. Continue with fraction-to-decimal conversion or flooring quantities.