How to use the flooring calculator
- Choose a Shape and enter the room dimensions, or use I know the area.
- Pick the Layout: straight lay (10% extra), diagonal (15%) or herringbone / chevron (20%).
- Enter the Coverage per box printed on the packaging.
- Optionally enter a price per box to estimate cost.
How it works
The calculator adds a waste allowance based on the layout: 10% for straight lay, 15% for diagonal and 20% for herringbone or chevron, because angled patterns need more cuts.
The total is divided by the coverage per box and rounded up to whole boxes. In metric mode, enter box coverage in square meters.
Area with extra = floor area × (1 + layout extra %)
Boxes = area with extra ÷ coverage per box, rounded up
Worked example
With the default inputs, a 12 × 10 ft room is 120 ft². With 10% extra for a straight lay that is 132 ft².
At 20 ft² per box, 132 ÷ 20 = 6.6, so buy 7 boxes. For a herringbone layout, 144 ft² needs 8 boxes.
Tips before you buy
- Keep one spare box from the same production lot for future repairs.
- Let flooring acclimate in the room before installing; follow the manufacturer’s instructions for timing.
- Include closets and the space under appliances such as dishwashers if the flooring runs there.
- Order underlayment and transition strips separately; they are not included here.
Frequently asked questions
How much extra flooring should I buy?
About 10% for a straight lay, 15% for diagonal and 20% for herringbone or chevron. Rooms with many corners may need more.
How many boxes of flooring do I need for a 12×10 room?
The room is 120 ft², or 132 ft² with 10% extra. At 20 ft² per box that is 7 boxes; check your product’s coverage per box.
Where do I find the coverage per box?
It is printed on the box or product listing, usually in square feet, for example 20.5 ft². Use that exact number.
Should I keep leftover flooring?
Yes. A spare box from the same lot makes it much easier to replace damaged boards later, since colors vary between runs.
Results are estimates based on the measurements you enter and typical material properties. Products vary, so check quantities with your supplier and follow product labels and your local building codes. Read the full disclaimer. Last reviewed October 9, 2026.