Square Footage Calculator

Calculate the area in square feet for rectangles, circles, triangles, trapezoids, and L-shapes. Perfect for flooring, paint, landscaping, tiling, and any home improvement project.

Square Footage Calculator

Area Formulas

Rectangle: A = length × width Circle: A = π × (diameter/2)² Triangle: A = (base × height) / 2 Trapezoid: A = (base1 + base2) / 2 × height Unit conversions: 1 sq ft = 144 sq in = 0.0929 sq m = 0.1111 sq yd 1 acre = 43,560 sq ft

Coverage Reference

MaterialCoverage per Unit
Interior paint (1 gal)~350–400 sq ft
Tile (12×12 box of 20)20 sq ft
Hardwood flooring (1 box)~20 sq ft
Carpet (sold by sq yd)÷ 9 = sq yd needed
Mulch (2 cu ft bag, 3" deep)~8 sq ft

Frequently Asked Questions

How do I calculate square footage of an irregular room?+
Divide the room into rectangles and/or other simple shapes. Calculate each section separately, then add them together. For L-shaped rooms, split into two rectangles along the inner corner.
How much extra should I order for flooring?+
Add 10% extra for rectangular rooms to account for cuts and waste. For diagonal installations or rooms with many angles, add 15%. Always order at least one extra box for future repairs.

About the Square Footage Calculator

This free square footage calculator helps you get accurate results instantly without needing to work through the math manually. Whether you need a quick estimate or a precise figure, having a reliable tool on hand saves time and reduces errors compared to manual calculation.

How to Use This Calculator

  1. Enter your values in the input fields above. Each field is labeled to guide you.
  2. Double-check your inputs — results are only as accurate as the numbers you enter.
  3. Click the Calculate button to see your result instantly.
  4. Use the result for your planning, budgeting, or decision-making.

Why Accurate Calculations Matter

Small errors in math calculations can compound into significant problems. A 1% miscalculation in a budget or measurement can translate to hundreds or thousands of dollars in wasted resources, or result in having to redo work entirely. This calculator uses the standard formulas and methods to give you reliable results you can trust.

Tips for Getting the Best Results

Frequently Asked Questions

Is this calculator free? Yes — completely free with no account, login, or payment required. Use it as many times as you need.

How accurate are the results? This calculator uses the standard formulas for square footage calculations. Results are accurate for typical use cases. For specialized or high-stakes applications, consult a professional.

Does it work on mobile? Yes. This calculator is fully responsive and works on smartphones, tablets, and desktops.