Square Footage Calculator: Room Size & Flooring Cost

What does 120 sq ft mean?

It means a room 12 ft by 10 ft covers 120 square feet — twelve feet one way and ten feet the other, multiplied. The room, the amount to buy and the material cost are three outputs, never the same number: the room is what you cover, the amount to buy is what you order, and the cost is what you pay. With 10% waste you buy 132 sq ft — 12 sq ft more than the room, for the cuts around the edges and the mistakes — and at $5.00 a square foot the material cost is $660.00. The room is also 13.333333 sq yd and 11.148365 sq m, and the amount to buy is 14.666667 sq yd and 12.263201 sq m.

Three things to check before you trust the number

Waste is not optional. Flooring is sold in boards and tiles, not in room shapes, so the cuts around the edges and the pattern matching always eat some of it. Ten percent is the usual allowance for a plain room; a patterned floor or a room with many corners needs 15% or 20%, and the calculator shows you what each one costs.

Measure the room, not the floor you see. Measure wall to wall, in feet, at the longest and widest points — a room that narrows at one end is measured at its widest, and the waste covers the rest. A room measured in inches needs converting first, and the area-calculator page takes any shape, not just a rectangle.

The price decides the bill, not the room. The same 132 sq ft costs $330.00 at $2.50 a square foot and $13,198.68 at $99.99 a square foot. Check the price per square foot against the quote before you trust the total.

Worked example

On the defaults: a room 12 ft by 10 ft, 10% waste, $5.00 a square foot.

1. Room: 12 × 10 = 120 sq ft.
2. Amount to buy: 120 × 1.10 = 132 sq ft.
3. Material cost: 132 × $5.00 = $660.00.
4. Room in square yards: 120 ÷ 9 = 13.333333 sq yd.
5. Room in square metres: 120 × 0.09290304 = 11.148365 sq m.
6. Smallest waste for 150 sq ft to buy: 25% — at 25% the amount to buy is 150.00 sq ft, and at 24% it is 148.80 sq ft.
7. Largest price for a cost of $700 or less: $5 — at $5 the cost is $660.00, and at $6 it is $792.00.
8. Fractional room: 9.5 ft by 11.25 ft is 106.88 sq ft (unrounded 106.875000), buy 117.56 sq ft (unrounded 117.562500), $558.42 (unrounded 558.421875).

Every branch, checked

• Room 15 ft by 12 ft, 10% waste, $5.00: Room 15 ft by 12 ft, 10% waste, $5.00: Room 180.00 sq ft; buy 198.00 sq ft; material cost $990.00. A room 15 ft by 12 ft — room 180.00 sq ft, buy 198.00 sq ft, $990.00.
• Room 10 ft by 10 ft, 5% waste, $3.00: Room 10 ft by 10 ft, 5% waste, $3.00: Room 100.00 sq ft; buy 105.00 sq ft; material cost $315.00. A room 10 ft by 10 ft — room 100.00 sq ft, buy 105.00 sq ft, $315.00.
• Room 20 ft by 15 ft, 15% waste, $8.00: Room 20 ft by 15 ft, 15% waste, $8.00: Room 300.00 sq ft; buy 345.00 sq ft; material cost $2,760.00. A room 20 ft by 15 ft — room 300.00 sq ft, buy 345.00 sq ft, $2,760.00.
• Room 8 ft by 8 ft, no waste, $4.00: Room 8 ft by 8 ft, no waste, $4.00: Room 64.00 sq ft; buy 64.00 sq ft; material cost $256.00. A room 8 ft by 8 ft with no waste — room 64.00 sq ft, buy 64.00 sq ft, $256.00.
• 20% waste: 20% waste: Room 120.00 sq ft; buy 144.00 sq ft; material cost $720.00. The defaults with 20% waste — room 120.00 sq ft, buy 144.00 sq ft, $720.00.
• $10.00 a square foot: $10.00 a square foot: Room 120.00 sq ft; buy 132.00 sq ft; material cost $1,320.00. The defaults at $10.00 a square foot — room 120.00 sq ft, buy 132.00 sq ft, $1,320.00.
• $2.50 a square foot: $2.50 a square foot: Room 120.00 sq ft; buy 132.00 sq ft; material cost $330.00. The defaults at $2.50 a square foot — room 120.00 sq ft, buy 132.00 sq ft, $330.00.
• Room 25 ft by 20 ft, 10% waste, $6.00: Room 25 ft by 20 ft, 10% waste, $6.00: Room 500.00 sq ft; buy 550.00 sq ft; material cost $3,300.00. A room 25 ft by 20 ft — room 500.00 sq ft, buy 550.00 sq ft, $3,300.00.
• Room 9.5 ft by 11.25 ft, 10% waste, $4.75: Room 9.5 ft by 11.25 ft, 10% waste, $4.75: Room 106.88 sq ft; buy 117.56 sq ft; material cost $558.42. A room 9.5 ft by 11.25 ft — room 106.88 sq ft, unrounded 106.875000, buy 117.56 sq ft, unrounded 117.562500, $558.42, unrounded 558.421875.
• Room 1 ft by 1 ft, 10% waste, $5.00: Room 1 ft by 1 ft, 10% waste, $5.00: Room 1.00 sq ft; buy 1.10 sq ft; material cost $5.50. A room 1 ft by 1 ft — room 1.00 sq ft, buy 1.10 sq ft, $5.50.

The reverses, worked backwards

• Smallest waste for the amount to buy to REACH at least 150 sq ft: 25% — at 25% the figures are Room 120.00 sq ft (unrounded 120.000000); buy 150.00 sq ft (unrounded 150.000000); material cost $750.00 (unrounded 750.000000); at the lower neighbor the figures are Room 120.00 sq ft (unrounded 120.000000); buy 148.80 sq ft (unrounded 148.800000); material cost $744.00 (unrounded 744.000000); at the upper neighbor the figures are Room 120.00 sq ft (unrounded 120.000000); buy 151.20 sq ft (unrounded 151.200000); material cost $756.00 (unrounded 756.000000) — verdict: STEP.
• Largest price for the material cost to STAY at or below $700: $5 — at $5 the figures are Room 120.00 sq ft (unrounded 120.000000); buy 132.00 sq ft (unrounded 132.000000); material cost $660.00 (unrounded 660.000000); at the lower neighbor the figures are Room 120.00 sq ft (unrounded 120.000000); buy 132.00 sq ft (unrounded 132.000000); material cost $792.00 (unrounded 792.000000); at the upper neighbor the figures are Room 120.00 sq ft (unrounded 120.000000); buy 132.00 sq ft (unrounded 132.000000); material cost $528.00 (unrounded 528.000000) — verdict: STEP.
• Smallest length for the room to REACH at least 150 sq ft: 15 ft — at 15 ft the figures are Room 150.00 sq ft (unrounded 150.000000); buy 165.00 sq ft (unrounded 165.000000); material cost $825.00 (unrounded 825.000000); at the lower neighbor the figures are Room 140.00 sq ft (unrounded 140.000000); buy 154.00 sq ft (unrounded 154.000000); material cost $770.00 (unrounded 770.000000); at the upper neighbor the figures are Room 160.00 sq ft (unrounded 160.000000); buy 176.00 sq ft (unrounded 176.000000); material cost $880.00 (unrounded 880.000000) — verdict: STEP.
• Smallest waste for the amount to buy to REACH at least 200 sq ft (room 15 ft by 10 ft): 34% — at 34% the figures are Room 150.00 sq ft (unrounded 150.000000); buy 201.00 sq ft (unrounded 201.000000); material cost $1,005.00 (unrounded 1005.000000); at the lower neighbor the figures are Room 150.00 sq ft (unrounded 150.000000); buy 199.50 sq ft (unrounded 199.500000); material cost $997.50 (unrounded 997.500000); at the upper neighbor the figures are Room 150.00 sq ft (unrounded 150.000000); buy 202.50 sq ft (unrounded 202.500000); material cost $1,012.50 (unrounded 1012.500000) — verdict: STEP.
• Largest waste for the amount to buy to STAY at or below 140 sq ft: 16% — at 16% the figures are Room 120.00 sq ft (unrounded 120.000000); buy 139.20 sq ft (unrounded 139.200000); material cost $696.00 (unrounded 696.000000); at the lower neighbor the figures are Room 120.00 sq ft (unrounded 120.000000); buy 140.40 sq ft (unrounded 140.400000); material cost $702.00 (unrounded 702.000000); at the upper neighbor the figures are Room 120.00 sq ft (unrounded 120.000000); buy 138.00 sq ft (unrounded 138.000000); material cost $690.00 (unrounded 690.000000) — verdict: STEP.
• Largest price for the material cost to STAY at or below $600: $4.50 — at $4.50 the figures are Room 120.00 sq ft (unrounded 120.000000); buy 132.00 sq ft (unrounded 132.000000); material cost $594.00 (unrounded 594.000000); at the lower neighbor the figures are Room 120.00 sq ft (unrounded 120.000000); buy 132.00 sq ft (unrounded 132.000000); material cost $660.00 (unrounded 660.000000); at the upper neighbor the figures are Room 120.00 sq ft (unrounded 120.000000); buy 132.00 sq ft (unrounded 132.000000); material cost $528.00 (unrounded 528.000000) — verdict: STEP.

What the defaults assume

The defaults are a room 12 ft by 10 ft — a small bedroom, near enough — with 10% waste and $5.00 a square foot, a mid-range laminate price. They are a starting point, not a benchmark: your room may be bigger, your waste may be higher for a pattern, and your price may be carpet, tile or hardwood. Change the four numbers to your own and the calculator recomputes instantly. Waste is not optional — check it against the pattern before you trust the order.

These notes repeat in every explainer section because this page is built to be read start to finish: the defaults are one room, not a standard; waste is not optional; measure the room, not the floor you see; and the price decides the bill, not the room.

Output · formula · meaning

Who uses this

• A homeowner ordering laminate for a bedroom — 12 ft by 10 ft is 120 sq ft, buy 132 sq ft, $660.00 at $5.00 a square foot.
• A renter checking whether the landlord’s flooring quote is fair — the room, the waste and the price, in three numbers.
• A contractor pricing a whole house — room by room, the waste and the cost, before the quote goes out.
• A DIYer deciding between carpet and tile — the same room, two prices, one calculator.

Accuracy & limitations

The calculator does the arithmetic exactly — the room is length times width, the amount to buy is the room times one plus the waste, and the material cost is the amount to buy times the price — and every figure on this page is checked against an independent model. What it cannot do is measure for you: a room that is not a rectangle needs measuring in pieces, and an L-shaped room is two rectangles, not one. It also prices materials only — labour, underlay, trim and delivery are separate, and the carpet-cost-calculator and tile-cost-calculator pages price those in. And the amount to buy is 117.56 sq ft, unrounded 117.562500, on fractional rooms — the page prints the unrounded figure so the rounding does not mislead you.

Cite this calculator

Room = length × width; amount to buy = room × (1 + waste / 100); material cost = amount to buy × price per square foot. On the defaults — a room 12 ft by 10 ft, waste 10%, price $5.00 a square foot — the room is 120 sq ft, the amount to buy is 132 sq ft, and the material cost is $660.00. Smallest waste for the amount to buy to reach at least 150 sq ft: 25%. Largest price for the material cost to stay at or below $700: $5. Smallest length for the room to reach at least 150 sq ft: 15 ft. Smallest waste for the amount to buy to reach at least 200 sq ft (room 15 ft by 10 ft): 34%. Largest waste for the amount to buy to stay at or below 140 sq ft: 16%. Largest price for the material cost to stay at or below $600: $4.50. Source: Bright Side Kit, brightoolbox.com.

Frequently asked questions