Flooring Calculator

Please fill in the required fields with values greater than 0.
–room area (sq ft)
–area with waste (sq ft)
–boxes needed
–estimated cost

Estimate only. Flooring is sold in full boxes, so you may have a little left over.

How to use this calculator

Enter the room length and width and choose how much extra to allow for waste. Add the coverage of one box and the price per square foot if you want the number of boxes and the cost.

The formula

Area = length × width
Area with waste = area × (1 + waste %)
Boxes = area with waste ÷ coverage per box (rounded up)

Example: A 15 ft × 12 ft room is 180 sq ft. With 10% waste you need 198 sq ft, which is 10 boxes of 20 sq ft. At $3.50 per sq ft that costs about $700.

Understanding your flooring estimate

This calculator tells you how many square feet of flooring to buy and how many boxes that takes. The “area with waste” figure is the one to order from. The extra covers cuts at walls, doorways and the end of each row, plus the occasional damaged plank.

Main factors that change how much flooring you need

  • Waste allowance: A simple rectangle needs less extra. Rooms with closets, angled walls or diagonal layouts need more.
  • Plank or tile size: Long planks can create more end waste in narrow rooms and hallways.
  • Box coverage: Flooring is sold by the full box, so the last box is often only partly used.
  • Number of rooms: Doing several connected rooms at once often uses offcuts more efficiently than one small room.

A real-world example

A 20 ft by 14 ft family room is 280 sq ft. With 10% waste, you need 308 sq ft. If a box of laminate covers 22 sq ft, that is exactly 14 boxes. At $2.50 per sq ft, the material cost is about $770. Switch to a diagonal layout with 15% waste and you would need about 322 sq ft, or 15 boxes.

Tips and common mistakes

  • Measure to the wall, not to the baseboard. The flooring runs under or up to the trim.
  • Round each measurement up to the next half foot rather than down.
  • Include closets and the area under doors if the same flooring goes there.
  • Remember the underlayment. Many floating floors need a separate pad unless one is already attached.
  • Let wood and laminate acclimate in the room before installing, following the manufacturer’s instructions.

Cost and planning advice

The price per square foot is only part of the budget. Add underlayment, transition strips, new baseboard or quarter-round, and any subfloor repair. If you hire an installer, labor is usually priced per square foot as well, and removal of old flooring is often extra. Ask whether the quote includes moving furniture and disposal.

Check the subfloor before ordering. Most floating floors need a flat surface, and dips or high spots may need leveling compound. Order all boxes from the same lot, and keep the receipt in case you can return unopened boxes.

Frequently asked questions

How much flooring do I need?
Multiply the room length by the width and add 5 to 15 percent for waste.
How much waste should I allow for flooring?
Allow 5 percent for simple rooms, 10 percent for most rooms and 15 percent for diagonal layouts or many cuts.
Should I measure each room separately?
Yes. Measure each room and add them together. For L-shaped rooms, split the room into rectangles.
Do I include closets and hallways?
Yes, if the same flooring will be installed there.
Should I buy extra boxes for future repairs?
It is a good idea to keep one spare box from the same batch, because colors can differ between batches.
Which direction should flooring planks run?
Planks usually look best running parallel to the longest wall or toward the main light source, such as a large window. This makes the room feel longer and hides seams. In narrow hallways, running planks lengthwise is typical. For solid wood over joists, planks are often laid across the joists for strength. Follow the manufacturer’s guidance.
Can I install new flooring over old flooring?
Floating floors can often go over flat, firmly attached vinyl, tile or wood. Carpet should always be removed first. Check that the added height still clears doors and appliances, and that the old floor is level. Glue-down and nail-down floors usually need a clean, bare subfloor for a proper bond.
How long does it take to install flooring in a room?
A DIYer can often lay a floating floor in an average bedroom in one day, not counting prep. Removing old flooring, fixing the subfloor and installing trim can add another day. Tile and glue-down floors take longer because the adhesive or mortar needs time to set before grouting or walking on it.