Flooring Calculator

The flooring calculator square feet method starts with the floor area. Measure the length and width of the room in feet, multiply them, and you have square feet. A 12 ft by 15 ft room is 180 sq ft. A 12 ft by 12 ft room is 144 sq ft, which is 13.38 sq m. A 10 ft by 20 ft room is 200 sq ft.

Measure at floor level from wall to wall, not along the baseboards, and include closets, alcoves and the space under a doorway if the flooring will run through it. Where the walls are not square, measure the longest length and the longest width, or split the room into rectangles. Round up to the next half foot.

For an L-shaped room, split the L into two rectangles that do not overlap, measure each and add the areas. For several rooms, measure each one and add them. The calculator has an L-shape option and a several-rooms option so you do not have to add by hand. If part of the floor stays bare, such as a kitchen island or built-in cabinets, enter that area in the not floored box and it is taken off.

The table below shows the floor area and the order size for common room sizes. It uses a 5% straight-lay allowance and 20 sq ft boxes, so you can check your own numbers against a familiar size.

Waste is the extra flooring you buy because planks must be cut to fit the ends of rows, the walls and the corners. The cut-off piece is often too short to use somewhere else. How much you lose depends on the layout pattern, the plank size and how many corners the room has.

The calculator uses three starting allowances. Straight lay, where rows run parallel to a wall, uses 5%. A flooring supplier's installation notes state that a minimum 5% cutting and waste allowance must be added to the net area, and that herringbone or chevron designs need a bigger one. A wood-flooring maker's herringbone guide asks for about 15% extra to cover cut loss, so herringbone uses 15%. Diagonal uses 10%, a planning mid-point between the two. These are typical figures, not rules, and every one can be replaced by choosing the custom option.

Use a higher number for narrow rooms, rooms with many corners, short planks and a first-time installer. Use a lower number only if your installer tells you so. A tile maker advises buying about 10% more than you think you need so you can replace damaged pieces later, and the same reasoning applies to planks, because a later order may not match the batch.

If you want to see the effect, compare the 144 sq ft example: straight gives 151.2 sq ft, diagonal 158.4 sq ft and herringbone 165.6 sq ft.

Flooring is sold in boxes, and each box states its coverage in square feet. Divide the area to order by the coverage and round up, because you cannot buy part of a box. For the 12 × 15 ft room, 189 sq ft divided by 20 sq ft per box is 9.45, so you buy 10 boxes. The calculator also shows how much is left over after whole boxes, here 11 sq ft, which is a handy reserve for repairs.

If you need to know the plank count, enter the plank length and width. The face area of a plank is length times width divided by 144, so a 48 in by 7 in plank covers 2.333 sq ft. The plank count is the area to order divided by that, rounded up. The calculator also divides the box coverage by the plank area to show planks per box, which should match the number on the carton. If it does not, trust the carton, because planks can have a tongue or a lip that is not part of the face area.

Two cautions. Boxes from different batches can differ a little in shade or gloss, so buy everything from one batch if you can. And if a box lists its coverage with a decimal, such as 19.8 sq ft, enter the decimal. A small difference per box adds up over a large order.

The same area method works for every material, but each one is bought in a different way. Vinyl plank and laminate come in boxes of planks, so use the box and plank inputs. Engineered wood also comes in boxes. Solid hardwood is often priced per square foot and delivered in bundles, and boards are graded, so some are set aside. Sheet vinyl comes off a roll, so check the roll width first, because the cut length depends on it.

For vinyl flooring, a 12 × 12 ft room needs 151.2 sq ft with 5% waste. For laminate, plan for the same 5% to 10% and keep the expansion gap at the walls, as one maker's guide says to leave a half inch between the wall and the last board in each row. For wood flooring, use 5% for straight boards and 15% for herringbone.

Concrete flooring is different because it is a volume job. Start with the same floor area, then multiply by the thickness in feet and divide by 27 to get cubic yards. A 200 sq ft slab 4 in thick is 66.7 cu ft, or 2.47 cu yd. For the gravel base under it, use the gravel calculator.

The table shows how each type is sold and what to enter.

Underlayment goes under floating floors such as laminate and many vinyl and engineered planks. Some planks have a pad attached, so check the box. Underlayment covers the floor, not the waste, so the calculator uses the net floor area and divides by the roll coverage, rounding up. A 180 sq ft room needs 2 rolls of 100 sq ft, with 20 sq ft spare. Roll sizes are examples, so enter the coverage printed on your roll.

Trim is measured along the perimeter. The calculator reports the room perimeter, which is 54 ft for the 12 × 15 ft room. Take off the width of doorways that will have a threshold instead, and add a few percent for mitred corners. Floating floors need an expansion gap at the walls, usually hidden by the baseboard or by quarter round, so plan for trim even if the old baseboard stays.

Transition strips go wherever the new floor meets a different material, a different height or a doorway where a floating floor must be allowed to move. Count the openings and buy one strip for each, sized to the opening. The calculator does not price transitions, so add them to your list by hand.

Enter your own price per square foot, or per square metre in metric mode. The default of $3 is only a placeholder. Cost uses whole boxes, because that is what you pay for: ten boxes of 20 sq ft at $3 per sq ft is $600.00. The price per sq ft changes the total quickly, as the cost table shows.

The estimate covers flooring only. It leaves out underlayment, adhesive, trim, transitions, removal of the old floor, subfloor repair and labour. Get a written quote for those, and compare it with your material estimate before you order. Ask whether returns of unopened boxes are accepted, because that makes a slightly generous order less risky.

When you compare quotes, compare the same unit. A US box may be quoted in square feet and a metric supplier in square metres, so use the conversion table. One square metre is 10.764 sq ft.

The most common mistakes are easy to avoid. People measure only the main room and forget the closet or hallway. They skip the waste allowance, or use the straight figure for a diagonal or herringbone lay. They round the box count down. They mix up square feet and square metres. They forget underlayment, trim and transitions. And they order the exact amount, then find a damaged box.

Some tips help. Measure twice and write the numbers on a sketch. Use the shape options instead of adding by hand. Enter the coverage from the box, not from a website. Keep one or two spare boxes, dry and flat, with the batch number written on them. Let the planks sit in the room for the time the maker recommends before you install them. And ask your installer which waste figure they use for the room.

This page is for ordering material. It is an estimate, so follow the flooring maker's instructions and your installer's advice, and confirm the quantities before you buy.

The calculator assumes straight walls and right angles. It handles one rectangle, one rectangular extension or up to three rooms, and a single area to subtract. Curved walls, stairs and complex layouts need to be split into rectangles by hand or measured by your installer. The waste allowances are planning figures. A herringbone floor in a small room can lose more than 15%, and a long straight room with long planks can lose less than 5%.

Related calculators on CalculatorPlanet may help with nearby jobs. For stairs that need flooring or nosing, use the stair calculator. For lumber and subfloor boards sold by volume, use the board foot calculator. For natural stone paving, use the stone calculator. For the base under a concrete floor, use the gravel calculator.