Feet and Inches Calculator
Calculator to add, subtract, multiply, divide, or convert feet and inches with fractions and decimals. Perfect for construction, carpentry, and home improvement projects.
Feet & Inches Calculator
Use feet or inches or both, fractions or decimals
Solution:
Enter values and click Calculate to see the step-by-step solution
What is the Feet and Inches Calculator?
The Feet and Inches Calculator is a powerful tool designed for performing arithmetic operations with imperial measurements. It allows you to add, subtract, multiply, and divide measurements expressed in feet and inches, including support for both fractions (like 3/4, 1/2, 5/8) and decimals (like 0.75, 0.5, 0.625).
This calculator is essential for professionals in construction, carpentry, architecture, engineering, and home improvement who work with imperial measurements daily. It eliminates the complexity of manual conversions and calculations, reducing errors and saving valuable time on job sites and in workshops.
Whether you're measuring lumber dimensions, calculating room sizes, planning deck construction, determining flooring requirements, or working on any project that uses feet and inches, this calculator provides accurate results with step-by-step solutions that show exactly how the calculation was performed.
How to Use the Feet and Inches Calculator
- Step 1: Enter First Measurement
Enter the feet and inches for your first measurement. You can use:
- • Whole numbers: 5 feet, 8 inches
- • Fractions: 3/4, 1/2, 5/8
- • Mixed numbers: 7 3/8, 61 3/4
- • Decimals: 0.75, 0.625
- • You can leave feet or inches blank if not needed
- Step 2: Select Operation
Choose the mathematical operation from the dropdown:
- • + for Addition
- • − for Subtraction
- • × for Multiplication
- • ÷ for Division
- Step 3: Enter Second Measurement
Enter the feet and inches for your second measurement using the same format options as the first measurement.
- Step 4: Calculate
Click the Calculate button to see the result in multiple formats:
- • Feet and inches with fractions (26 ft 9 1/8 in)
- • Total feet as a decimal (26.7604 ft)
- • Total inches with fractions (321 1/8 in)
- • Total inches as a decimal (321.125 in)
- Step 5: Review Solution
Check the step-by-step solution to understand how the result was calculated, including the conversion to inches, the operation performed, and the conversion back to feet and inches.
Understanding Feet and Inches Calculations
Basic Conversion
The fundamental relationship between feet and inches:
1 foot = 12 inches
1 inch = 1/12 foot ≈ 0.0833 feet
Addition Process
To add feet and inches:
- 1. Convert both measurements to total inches
- 2. Add the total inches together
- 3. Divide by 12 to get feet (whole number part)
- 4. The remainder is the inches
Example:
5 ft 8 in + 3 ft 9 in
= (5×12 + 8) + (3×12 + 9)
= 68 in + 45 in = 113 in
= 9 ft 5 in
Working with Fractions
When working with fractional inches (common in carpentry):
- • 1/2 inch = 0.5 inches
- • 1/4 inch = 0.25 inches
- • 3/4 inch = 0.75 inches
- • 1/8 inch = 0.125 inches
- • 3/8 inch = 0.375 inches
- • 5/8 inch = 0.625 inches
- • 7/8 inch = 0.875 inches
Common Applications
Construction & Building
- • Measuring wall lengths and heights
- • Calculating floor and ceiling dimensions
- • Determining stud spacing (16" or 24" on center)
- • Planning door and window openings
- • Calculating total material lengths
- • Foundation measurements
- • Roofing calculations
Carpentry & Woodworking
- • Cutting lumber to precise lengths
- • Cabinet and furniture dimensions
- • Trim and molding measurements
- • Deck board spacing and layout
- • Stair tread and riser calculations
- • Shelf spacing and sizing
- • Door and drawer measurements
Home Improvement
- • Flooring and tile layout planning
- • Paint coverage area calculations
- • Wallpaper measurements
- • Furniture placement and spacing
- • Room dimension verification
- • Countertop measurements
- • Window treatment sizing
Professional Trades
- • HVAC duct sizing and layout
- • Plumbing pipe measurements
- • Electrical conduit runs
- • Concrete formwork dimensions
- • Landscaping and fencing
- • Pool and spa installations
- • Equipment spacing requirements
Common Fraction Conversions
| Fraction | Decimal | Common Use |
|---|---|---|
| 1/16" | 0.0625" | Fine woodworking, precision cuts |
| 1/8" | 0.125" | Common measurement increment |
| 3/16" | 0.1875" | Detailed carpentry work |
| 1/4" | 0.25" | Standard spacing, drill bits |
| 3/8" | 0.375" | Bolt sizes, lumber thickness |
| 1/2" | 0.5" | Plywood, drywall thickness |
| 5/8" | 0.625" | Drywall, plywood thickness |
| 3/4" | 0.75" | Standard lumber, plywood |
| 7/8" | 0.875" | Specialty applications |
Tips for Accurate Measurements
Use Quality Measuring Tools
Invest in a good quality tape measure with clear markings. Check that it's properly calibrated.
Measure Twice, Cut Once
Always verify measurements before cutting materials. Double-check calculations to avoid costly mistakes.
Account for Material Thickness
Remember to factor in the thickness of materials when calculating cuts and joints.
Keep Consistent Units
Stick to feet and inches throughout a project to avoid confusion and calculation errors.
Mark Clearly
Use clear, precise markings on materials. Label measurements to avoid mix-ups.
Account for Tolerances
Leave appropriate gaps for expansion, especially with wood products that can swell with moisture.
Check Square and Level
Ensure corners are square (90°) and surfaces are level before final measurements.
Document Everything
Keep written records of all measurements and calculations for reference and verification.
Frequently Asked Questions (FAQ)
How do I add feet and inches with fractions?
To add feet and inches with fractions, first convert both measurements to total inches (multiply feet by 12 and add inches). Add the two total inch values together. Then divide the result by 12 to get feet (the whole number) and the remainder is the inches. For fractions, convert to decimals (e.g., 3/4 = 0.75), perform the calculation, then convert back to the nearest fraction if needed.
Can I enter just inches or just feet?
Yes! You can leave either the feet or inches field blank. If you're measuring something that's only in inches (like 61 3/4 inches), just enter that in the inches field and leave feet blank. If you have a measurement that's only whole feet with no extra inches, enter the feet and leave inches blank or enter 0.
What fractions can I use?
You can use any fraction, but common carpentry fractions work best: 1/2, 1/4, 3/4, 1/8, 3/8, 5/8, 7/8, and 1/16. You can also use mixed numbers like "7 3/8" or "61 3/4". The calculator will convert these to decimals, perform the calculation, and convert back to fractional form in the answer.
How accurate is the calculator?
The calculator performs all calculations with high precision (up to 10 decimal places internally) and displays results to 4 decimal places for feet and 3 decimal places for inches. Fractions are approximated to the nearest 1/8 inch for practical use in construction and carpentry, which is the standard precision for most tape measures.
Why do I get negative results in subtraction?
You'll get a negative result when subtracting a larger measurement from a smaller one. For example, 5 ft 3 in minus 8 ft 7 in = -3 ft -4 in. This indicates the second measurement is larger by that amount. In practical applications, you may need to reverse the order of subtraction or interpret the negative result as a deficit or shortage.
When would I multiply or divide feet and inches?
Multiplication is useful when calculating total lengths of multiple identical pieces (e.g., 5 boards each 8 ft 3 in long). Division is helpful for splitting measurements into equal parts (e.g., dividing a 10 ft board into 3 equal pieces) or calculating unit rates. Note that multiplication and division results may need interpretation based on your specific application.
How do I convert between feet and inches?
To convert feet to inches, multiply by 12 (e.g., 5 ft = 5 × 12 = 60 inches). To convert inches to feet, divide by 12 (e.g., 36 inches = 36 ÷ 12 = 3 feet). For mixed measurements like 5 ft 8 in, convert the feet to inches first (5 × 12 = 60), then add the inches (60 + 8 = 68 total inches).
What if my inches exceed 12?
The calculator automatically handles inches greater than 12 by converting them to feet. For example, if you enter 0 feet and 25 inches, the calculator will show the result as 2 ft 1 in (since 25 ÷ 12 = 2 with remainder 1). This is helpful when you're working with measurements from a tape measure that shows total inches.
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