How to Measure Countertop Area by Shape Using a Square Foot Calculator
Planning your new countertop starts with one of the most important steps: getting the measurements right. Knowing how to measure different shapes accurately allows you to use our square foot calculator effectively, so you get the right amount of material, stay within budget, and avoid surprises during installation.
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Here’s how to measure the most common countertop shapes so you can plug them into our square foot calculator with confidence.
1. Rectangle or Square
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This is the most common shape for countertop sections like islands or straight counters
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How to Measure:
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Measure the length and width in inches.
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Multiply the two measurements to get the area in square inches.
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Divide by 144 to convert to square feet.
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Formula:
(Length × Width) ÷ 144 = Square Feet
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Example:
60 inches × 24 inches = 1,440 in²
1,440 ÷ 144 = 10 sq ft
2. Circle or Round Ends
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You may have circular sinks, table tops, or rounded edges to include.
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How to Measure:
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Measure the diameter (the widest part across).
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Divide the diameter by 2 to get the radius.
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Use the formula for the area of a circle, then divide by 144.
Formula:
(π × Radius²) ÷ 144 = Square Feet
(Use 3.14 for π)
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Example:
Diameter = 36 inches → Radius = 18 inches
(3.14 × 18²) ÷ 144 = (3.14 × 324) ÷ 144 ≈ 7.06 sq ft
3. Triangle
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Some counters, breakfast bars, or outdoor spaces may have angled shapes.
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How to Measure:
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Measure the base and height in inches.
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Multiply and divide as shown below.
Formula:
(Base × Height ÷ 2) ÷ 144 = Square Feet
Example:
Base = 60 inches, Height = 30 inches
(60 × 30 ÷ 2) ÷ 144 = 900 ÷ 144 = 6.25 sq ft
4. Trapezoid
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Used for counters that have angled sides, like corner spaces or custom islands.
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How to Measure:
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Measure the top base, bottom base, and height in inches.
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Add the two bases, multiply by the height, divide by 2, then by 144.
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Formula:
[(Base1 + Base2) × Height ÷ 2] ÷ 144 = Square Feet
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Example:
Top = 40 in, Bottom = 60 in, Height = 24 in
[(40 + 60) × 24 ÷ 2] ÷ 144 = (100 × 24 ÷ 2) ÷ 144 = 1,200 ÷ 144 = 8.33 sq ft
Why Use a Square Foot Calculator for Your Countertops?
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Measuring by hand is only half the equation. A good square foot calculator helps you:
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Save money by calculating the right amount of material.
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Avoid waste and unnecessary offcuts.
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Get accurate estimates when requesting quotes or comparing stone options.
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Make planning easier, especially if you’re working with a contractor or designer.
When you enter your measurements into our square foot calculator, you’re ensuring that your countertop project starts with clarity, not guesswork.
Final Measuring Tips:
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Always measure in inches, even if your space feels "about a foot" long—details matter.
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If your countertop has multiple shapes, break it down and calculate each one separately.
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It’s better to round up slightly—you can always use leftover material for a vanity or backsplash.
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Need Help?
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If you're unsure about how to measure your countertops or how to use the square foot calculator, just give us a call. Our team at Southern Stoneworks is always happy to walk you through it or even schedule a professional measurement for you.
Our Services
At Southern StoneWorks, we specialize in custom countertop installation, fabrication, and repair for kitchens, bathrooms, and outdoor spaces.
Your kitchen is more than just a cooking space—it’s the heart of your home. Your countertops should reflect that. Whether you need a durable, heat-resistant surface for daily cooking or a sleek, modern design, we offer granite, quartz, and marble countertops to match your vision.
Bathrooms should be both practical and luxurious. Our bathroom countertops are designed to resist moisture, stains, and everyday wear, ensuring long-lasting beauty. From classic marble to easy-care quartz, we have the perfect solution for your space.
Florida’s heat and humidity demand countertops that can withstand the elements. Our weather-resistant stone countertops are ideal for outdoor kitchens, bars, and entertainment areas, combining durability with stunning design.
Need help choosing the perfect countertop? Call us today!
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