Laminate is not bought by the square foot or metre; it is bought in packs that each cover a stated area. So the calculation has three steps rather than one: measure the floor, add the waste your layout will actually produce, then divide by the pack coverage and round up. The waste is the part that varies, because a square room laid straight wastes very little and a room with several doorways laid diagonally wastes a great deal.
How to work out how much laminate flooring I need: measure room by room
Length by width for each rectangle, added together, with doorways and alcoves measured separately rather than guessed. Take laminate flooring measurements at floor level rather than from a plan, because skirting, out-of-square walls and old thresholds all move the number.
A laminate floor calculator should add waste for the layout, not a flat percentage
Straight lay in a simple rectangle wastes least; diagonal lay, herringbone, and rooms with many cuts waste considerably more. Add what your own offcuts have told you for that layout, and remember that the first and last rows of every room produce cuts whether the room is simple or not.
The laminate calculator's last step: divide by the pack, then buy one more
Pack coverage is printed on the pack and differs between products, which is why a pack count from one product does not transfer to another. Round up, and consider one spare pack from the same batch: a replacement bought later rarely matches, and a damaged board two years in is otherwise a whole-room problem.
Questions people ask about laminate flooring calculator
How much extra should I buy?
Enough to cover the cuts your layout produces plus a margin for damage, and ideally one spare pack from the same batch for future repairs. The exact allowance is a property of the room and the pattern rather than a universal figure.
Do laminate flooring measurements include doorways and alcoves?
Measure them and include them; they are floor that needs covering and they also generate the awkward cuts. Leaving them out is the most common reason a job is one pack short on the last afternoon.
Does the plank direction change the amount?
It changes the waste rather than the area. Laying along the longest wall usually produces fewer cuts than laying across it, and any diagonal or patterned layout increases waste noticeably.