Kitchen Countertop Square Foot Calculator

Calculator Form

Enter lengths in feet unless the field label says inches.

Section A Length (ft)

Primary straight countertop run length.

Section A Depth (in)

Common depth is around 25 inches.

Section B Length (ft)

Use second run or L-shape section.

Section B Depth (in)

Enter zero if not used.

Island Length (ft)

Island countertop length.

Island Width (ft)

Island countertop width or depth.

Backsplash Length (ft)

Total linear backsplash length.

Backsplash Height (in)

Standard backsplash often starts at 4 inches.

Front Overhang Length (ft)

Combined length of front overhang edges.

Front Overhang Depth (in)

Common front overhang is about 1 to 1.5 inches.

Side Overhang Length (ft)

Exposed side overhang edge length.

Side Overhang Depth (in)

Enter side overhang depth if included.

Sink Cutout Area (sq ft)

Subtract undermount or drop-in sink opening area.

Cooktop Cutout Area (sq ft)

Subtract appliance opening if needed.

Waste Allowance (%)

Typical allowance ranges from 5% to 15%.

Material Cost Rate ($ / sq ft)

Used for material estimate only.

Installation Cost Rate ($ / sq ft)

Used for labor and fitting estimate.

Reset Values

Formula Used

Section Area = Length (ft) × Depth (in ÷ 12)

Island Area = Island Length (ft) × Island Width (ft)

Backsplash Area = Backsplash Length (ft) × Backsplash Height (in ÷ 12)

Overhang Area = Overhang Length (ft) × Overhang Depth (in ÷ 12)

Gross Area = Section A + Section B + Island + Backsplash + Front Overhang + Side Overhang

Net Area = Gross Area − Sink Cutout − Cooktop Cutout

Total Order Area = Net Area × (1 + Waste % ÷ 100)

Estimated Total Cost = (Total Order Area × Material Rate) + (Total Order Area × Installation Rate)

How to Use This Calculator

Measure each countertop run in feet.
Enter run depths in inches for more accurate sizing.
Add island dimensions if your kitchen includes one.
Enter backsplash length and height when it uses the same slab or material estimate.
Add front and side overhang measurements for exposed edges.
Subtract sink and cooktop openings using their cutout areas.
Apply a waste percentage for trimming, seams, pattern matching, and breakage allowance.
Enter material and installation rates to generate a quick project cost estimate.
Press the calculate button to view totals, chart data, and export options.

Example Data Table

Example Item	Input	Example Value
Main Run Length	Section A Length	12 ft
Main Run Depth	Section A Depth	25 in
Secondary Run Length	Section B Length	8 ft
Secondary Run Depth	Section B Depth	25 in
Island Size	Island Length × Width	7 ft × 3 ft
Backsplash	Length × Height	20 ft × 4 in
Openings	Sink + Cooktop Cutouts	5.5 sq ft
Waste	Waste Percentage	10%
Material Rate	Cost per sq ft	$65
Installation Rate	Cost per sq ft	$25

Frequently Asked Questions

1. What does this calculator measure?

This calculator estimates countertop square footage for straight runs, islands, backsplashes, and overhangs. It also subtracts cutouts, adds waste, and can estimate material and installation costs.

2. Should I include backsplash in square footage?

Include backsplash when it is made from the same material and should be priced within the same estimate. If your backsplash uses different material, leave those fields at zero.

3. Why is waste allowance important?

Waste covers trimming, corner shaping, pattern alignment, breakage risk, and seam adjustments. Without waste, ordered material may be too low for fabrication and installation.

4. How do I measure countertop depth correctly?

Measure from the wall to the finished front edge. Standard kitchen depths are often around 25 inches, but custom layouts and overhang details can change that dimension.

5. Do sink and cooktop openings reduce material quantity?

They can reduce usable square footage in a planning estimate. However, some fabricators still price by slab usage, edge work, and complexity, not only by net cutout area.

6. What waste percentage should I use?

Many projects use 5% to 15%. Simple layouts may need less, while patterned materials, large islands, seam-heavy kitchens, and fragile stone may need more.

7. Can I use this for laminate, quartz, granite, or solid surface?

Yes. The area formula works for most countertop materials. You only need to adjust cost rates and waste allowance to reflect the specific material and fabrication process.

8. Is this calculator a final fabrication quote?

No. It provides a strong planning estimate. Final quotes can also include seam location, edge profile, thickness, template visits, delivery, sink support, and finish details.