Feet and Inches Calculator
Add, subtract, multiply, and divide feet and inches with fractions. Convert between decimal feet, total inches, and metric units.
Result
Feet and Inches
9' 3"
With fractions
Metric
2.8194
meters
Calculator Mode
Fraction Precision
Operation
Value 1
Value 2
Quick Reference
Common Lumber Lengths
Sheet Goods
Decimal to Fraction Reference
| Fraction | Decimal | mm |
|---|---|---|
| 1/16" | 0.0625 | 1.59 |
| 1/8" | 0.125 | 3.18 |
| 3/16" | 0.1875 | 4.76 |
| 1/4" | 0.25 | 6.35 |
| 5/16" | 0.3125 | 7.94 |
| 3/8" | 0.375 | 9.53 |
| 7/16" | 0.4375 | 11.11 |
| 1/2" | 0.5 | 12.70 |
| 9/16" | 0.5625 | 14.29 |
| 5/8" | 0.625 | 15.88 |
| 11/16" | 0.6875 | 17.46 |
| 3/4" | 0.75 | 19.05 |
| 13/16" | 0.8125 | 20.64 |
| 7/8" | 0.875 | 22.23 |
| 15/16" | 0.9375 | 23.81 |
| 1" | 1.0 | 25.40 |
Quick Answer
To add feet and inches: First add the feet, then add the inches. If inches exceed 12, convert to feet. Example: 5'6" + 3'9" = 8'15" = 9'3" (15" - 12" = 3", carry 1 foot). To multiply: Convert to decimal feet or total inches first, multiply, then convert back. Example: 4'6" x 3 = 4.5 x 3 = 13.5 feet = 13'6".
Key Facts
- 12 inches = 1 foot
- 3 feet = 1 yard = 36 inches
- 1 foot = 0.3048 meters = 30.48 cm
- 1 inch = 2.54 cm = 25.4 mm
- Common fractions: 1/16", 1/8", 3/16", 1/4", 5/16", 3/8", 7/16", 1/2"
- Standard lumber: 8', 10', 12', 14', 16' lengths
- Plywood/drywall: 4' x 8' sheets
- To convert inches to feet: divide by 12
- To convert decimal feet to inches: multiply decimal by 12
Frequently Asked Questions
Add the feet together, then add the inches together. If the inches total 12 or more, subtract 12 and add 1 to the feet. Example: 5'6" + 3'9" = 8'15". Since 15" > 12", subtract 12 (15-12=3) and add 1 foot. Result: 9'3".
Subtract inches first. If you need to borrow, take 1 foot (12 inches) from the feet. Example: 10'4" - 3'8". You can't subtract 8 from 4, so borrow: 9'16" - 3'8" = 6'8".
Convert to decimal feet first (divide inches by 12 and add to feet), multiply, then convert back. Example: 4'6" x 3 = 4.5 ft x 3 = 13.5 ft = 13'6". Alternative: convert to inches (54"), multiply (162"), divide by 12 (13.5').
Convert to total inches, divide, then convert back to feet and inches. Example: 12'3" / 3 = 147" / 3 = 49" = 4'1".
The whole number is feet. Multiply the decimal by 12 to get inches. Example: 5.75 feet = 5 feet + (0.75 x 12) inches = 5'9".
Common fractions: 1/16" (finest typical), 1/8", 3/16", 1/4", 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4", 13/16", 7/8", 15/16". On a tape measure, 1/16" marks are smallest, 1/8" slightly longer, 1/4" longer still, 1/2" second longest, inch marks longest.
Standard lumber lengths: 8', 10', 12', 14', 16', 20'. Nominal vs actual: 2x4 is actually 1.5" x 3.5", 2x6 is 1.5" x 5.5", 2x8 is 1.5" x 7.25". Sheet goods: 4' x 8' (plywood, drywall, OSB).
First convert to total inches. Multiply inches by 2.54 to get centimeters, or by 25.4 for millimeters. Example: 5'6" = 66" = 66 x 2.54 = 167.64 cm = 1.6764 m.
Result
Feet and Inches
9' 3"
With fractions
Metric
2.8194
meters