Ft to Sq Ft Calculator
Convert linear feet to square feet by adding the material width. This is useful for flooring strips, boards, panels, turf rolls, and other rectangular materials.
How to convert ft to sq ft (the right way)
A common question is: “How do I convert feet to square feet?” The key idea is that feet (ft) measures one dimension (length), while square feet (sq ft) measures area (length × width). So you cannot convert from ft to sq ft with only one number.
To find area in square feet, you need:
- Length in feet
- Width in feet (or inches converted to feet)
Formula
When width is already in feet
Square Feet = Length (ft) × Width (ft)
When width is in inches
First convert inches to feet, then multiply:
Square Feet = Length (ft) × (Width in inches ÷ 12)
Step-by-step usage
- Enter the total linear feet.
- Enter the width of the material.
- Choose whether the width is in inches or feet.
- Optionally enter a waste factor (often 5% to 15%).
- Click Calculate to get base area and adjusted area.
Quick reference table
| Length (ft) | Width | Result (sq ft) |
|---|---|---|
| 10 | 12 in (1 ft) | 10 sq ft |
| 25 | 18 in (1.5 ft) | 37.5 sq ft |
| 40 | 24 in (2 ft) | 80 sq ft |
| 100 | 6 in (0.5 ft) | 50 sq ft |
Where this calculator is useful
Flooring and trim planning
If you know linear feet of planks and the board width, you can estimate total square footage coverage before purchase.
Roll materials
Artificial turf, underlayment, insulation, and some fabrics are sold by length with fixed width. Convert to sq ft to compare price per area.
Construction and renovation estimates
Contractors often compare materials using square-foot pricing. This calculator helps standardize measurements quickly.
Common mistakes to avoid
- Using only one dimension: You need both length and width for area.
- Forgetting inch-to-foot conversion: Divide inches by 12.
- Skipping waste: Real projects usually require extra material.
- Rounding too early: Keep decimals until final totals.
FAQ
Can I directly convert 20 ft into sq ft?
No. You need width as a second measurement. For example, 20 ft × 2 ft = 40 sq ft.
What is the difference between linear feet and square feet?
Linear feet measures length only. Square feet measures area (length × width).
How much extra material should I add?
A typical overage is 5% to 15%, depending on cuts, pattern matching, and project complexity.
Final note
This ft to sq ft calculator is designed for quick, practical estimating. For ordering material, always verify product dimensions, packaging units, and manufacturer recommendations.