How much flooring do I need... a guide to measurement

by Becky Kleanthous for

Number crunching for new flooring

Getting new flooring can really transform a room, so it's often an exciting prospect to go shopping for floorboards or tiles.

But if the thought of measuring and calculating floorspace has you anything less than thrilled, then rest assured that you will find this guide indispensable.

Just read on to ensure your DIY dream doesn't become a DI-WHYYY disaster!

Calculate your floor's square feet

Whichever choice you've opted for... tiles or floorboards, you first need to calculate the area of your room in square feet.

When you work out the area of the floor you're updating, do remember that this has got to include nooks, cupboards and window bays, so measure carefully!

To calculate the square feet measurement, multiply the length of the room by the width. The total is the area of the floor.

20' width X 16' length = 320 square feet (ft²)

To have absolute confidence with this step, use the square footage calculator available here.

If you've got an awkwardly shaped room, or you're measuring for several rooms all needing the same new surface, sketch out the floor-plan and divide it into regular shapes. Just calculate the square footage of each component, then add them together to get the total.

For laminate and hardwood floorboards or any "strip" flooring

Buy a surplus of 5-10% (a percentage calculator is here, if needed) based on your calculations in Step 1. There will be waste since

Buying the precise area of floorboards is guaranteed to leave you with a sad patch of naked floorspace, so make sure to get extra!

Just multiply the square footage by 1.05 to see what a 5% increase looks like, or by 1.1 to get the figure with a 10% increase.

For example: 320ft² x 1.1 = 352ft²

Wood, Ceramic, Vinyl, Linoleum and Stone floor tiles

Once you know the square footage of the room, it's time to calculate how many tiles you need to fill the space. Of course, this will depend on the size of tile you are using, so consult the list below to find the magic number you need. Then, just divide the area of the room by the magic number.

If your tile size is… your magic number is…

4" x 4" … 0.1089
6" x 6" … 0.25
9" x 9" … 0.5625
12" x 12" … 1
18" x 18" … 2.25

For example, a 320ft² room is going to be updated with 18" flagstone floor tiles,
so you divide 320 by the magic number, which for 18" x 18" is 2.25. 320 ÷ 2.25 = 142.2 tiles

To account for waste (as we did for the strip flooring), simply multiply the number of tiles by 1.05 for a 5% increase or 1.1 for a 10% increase.

For example, 142.2 x 1.10 = 156 tiles (always round up the decimal point to give a more generous margin)

And, of course the final step is...

Obvious to those of us who've done lots of projects, but not so obvious the newly-minted handymen. ALWAYS BUY A FEW EXTRA BOXES!!

Both tiles and manufactured flooring can vary in color from batch to batch. If you go back to the store later, especially if you purchase the materials months before the project starts, the new material may not match the material you purchased. This often occurs with both DIY and hired-installer jobs... stuff happens!)

Also, though ceramic floor tile is durable there are bound to be chipped and cracked tiles over the years. Purchasing a few extra boxes (beyond the normal waste we added to your calculations earlier) at the onset of the project assures you a perfect match should you need to do repairs years down the road!

Nowadays, with the exception of special orders most tile and flooring retailers are glad to accept returns so overbuying is not so much of a problem as it was years ago!!

And that's all there is to it! Don't be floored by new flooring: just follow these easy steps.