How to Calculate Square Feet for Marble and Granite: Floors, Kitchens and Stairs

Marble and granite are priced per square foot (sq ft), so the first step to any budget is measuring the area. The maths is simple, but there are a few traps: inches vs feet, L-shaped counters, stair risers and wastage. This guide walks you through the process step by step, with worked examples for a floor, a kitchen counter and a staircase, so you can arrive at the showroom with numbers you trust.

What you need

• A steel measuring tape, at least 5 metres (16 ft) long. Cloth tapes stretch and give wrong readings.
• A notebook or your phone, and a pencil for a rough sketch of each area.
• A calculator.
• A helper to hold the other end of the tape on long walls and stairs.
• Your house drawings, if you have them, to cross-check room sizes.

Measure in good daylight. In a Lahore summer, early morning is the most comfortable time to measure a roof terrace, porch or staircase that sits in direct sun.

Step 1: Learn the basic formula

Area (sq ft) = length (ft) × width (ft)

If you measured in inches, divide each measurement by 12 first. For example, 30 inches = 2.5 ft. Or multiply in inches and divide the result by 144.

Pick one unit and stick with it for the whole job. Mixing feet for one wall and inches for the next is the most common reason a total comes out wrong. If your mason or contractor gives you sizes in feet and inches, such as 12 ft 6 in, convert the inches into a decimal of a foot: 6 ÷ 12 = 0.5, so 12 ft 6 in = 12.5 ft.

Step 2: Sketch the area and split it into rectangles

Draw a simple plan of each room or surface. It does not need to be to scale. Mark doors, columns, built-in cupboards and any steps. Then split the shape into rectangles. A room with a bay or an alcove becomes two or three rectangles; an L-shaped lounge becomes two. Calculate each rectangle on its own and add them together at the end.

Measure each wall at two points, near the floor and about a metre up, because walls in older houses are not always straight or square. Use the larger figure.

Step 3: Measure a room floor (Example 1)

A bedroom measures 14 ft × 12 ft.

• Area = 14 × 12 = 168 sq ft
• Add about 10% for cutting and spares: 168 × 1.10 ≈ 185 sq ft to order

For an irregular room, split it into rectangles, calculate each, and add them up. Remember skirting: measure the wall length and multiply by the skirting height (for example 4 inches = 0.33 ft).

So if the same bedroom has 52 ft of wall (14 + 12 + 14 + 12) and 4-inch skirting, that is 52 × 0.33 ≈ 17 sq ft of skirting. Subtract door openings from the wall length before you multiply, because skirting stops at each door frame.

Step 4: Measure an L-shaped kitchen counter (Example 2)

One run is 10 ft long, the other is 6 ft, both 2 ft deep.

• Run A: 10 × 2 = 20 sq ft
• Run B: 6 × 2 = 12 sq ft
• The corner square is counted twice, so subtract it: 2 × 2 = 4 sq ft
• Total = 20 + 12 − 4 = 28 sq ft

Add backsplash strips if you want stone on the wall (length × height), and the front edge strip if you choose a mitred edge (see edge profiles). Counters are cut from whole slabs, so the final figure depends on slab size and layout; we confirm it after measuring.

Measure the counter depth from the wall to where you want the front edge, not just the cabinet depth, so you include the small overhang. In a Pakistani kitchen where the stove area gets heavy use with ghee and tadka, many families also run the backsplash full height behind the hob, which adds noticeably to the total.

Step 5: Measure a staircase (Example 3)

A stair is 4 ft wide, with 14 steps. Each tread (the part you step on) is 11 inches deep, and each riser (the vertical part) is 6.5 inches high.

• Tread: 4 × (11 ÷ 12) = 3.67 sq ft
• Riser: 4 × (6.5 ÷ 12) = 2.17 sq ft
• Per step: 3.67 + 2.17 = 5.84 sq ft
• 14 steps: 14 × 5.84 ≈ 82 sq ft, plus landings and side skirting

Measure the tread depth including the nosing that sticks out over the riser below. Landings are simple rectangles, so measure them like a small floor. Side skirting on a staircase runs at an angle, so measure its length along the slope and multiply by its height.

Our staircase guide covers stone choice and nosing for stairs.

Step 6: Add wastage

Stone is cut to fit, and some pieces are lost to cuts around doors, corners and pipes. A few spares are also useful in case a tile is damaged in future.

Always order from the same lot. Natural stone varies between batches, and buying a few extra pieces later may not match.

Step 7: Add up a whole-house list

For a full house, make a simple table with one line per area. It keeps everything in one place and makes it easy to compare quotes.

Then apply the right wastage figure to each line, not one figure to the whole total, because a plain floor and a patterned border need very different allowances.

Step 8: Turn square feet into a budget

Multiply your total by the stone's rate. For example, 185 sq ft of Botticino marble at an estimated Rs 850 – 1,000 per sq ft comes to roughly Rs 157,000 – 185,000 for the stone alone. Rates are listed on every stone's page, and our price guide explains what else to budget for.

Remember that the stone rate is only one part of the cost. Fixing, polishing, edge work and materials such as adhesive are usually quoted separately, so ask each supplier what their figure includes before comparing.

Common mistakes

• Mixing inches and feet. Convert everything to one unit before multiplying.
• Counting the corner twice on L-shaped and U-shaped counters.
• Forgetting risers, landings and skirting on staircases.
• Using one wastage figure for everything. Diagonal and patterned layouts need more.
• Measuring only once. Measure twice, and on two levels of each wall.
• Ordering too little and topping up later. A later batch may not match the first.
• Ignoring backsplashes and edge strips on kitchen and vanity counters.

Not sure which stone to price? Browse all marble types and compare rates side by side.

Send us your measurements or a simple sketch on WhatsApp, and we will check the numbers and suggest a layout that reduces waste.