CALCULATING CARPET

[WILLWONKER]

Need to replace carpets, lounge/ dining room easy to do , so how do they calculate stairs and landing
so i have a good idea of the cost . i have 11 steps with 190mm rise x 240mm tred x 800mm width, landing 3.50 x 1.20mm, and half landing 900x1.70, have tryed to work this out and my estimate is about
11/12 sq meters, am i way out or near on, don't want to get over charged. the steps are approx due to carpet already being down with underlay so will have to give and take a little there. thanks

[buildersmate]

Calculating square metreage in this way is kind of irrelevant, unless you are DIY.
When the supply company measures up, they will calculate how to best fit your shapes into the carpet roll, which generally comes 4 metres wide.
Whatever happens, you will have to pay for the 4 metres x the total length required off the roll.
There are 'rules' - you can't turn a piece through 90 degrees in relation to the other pieces (because the carpet pile lays a certain way and it will look a different shade of colour.
There may also be quite a saving from joining certain pieces together - again supply companies work this out and give you options.

[WILLWONKER]

Thank you for your comprehensive answer, I see the only way to go then wil be three quotes of the same or similar carpet to achieve a true cost.

[magicmerlin]

Stair tread = 11 x 0.24 x 0.8 = 2.112 m2
Stair riser = 11 x 0.19 x 0.8 = 1.672 m2
Landing = 3.5 x 1.2 = 4.2 m2
Half landing = 1.7 x 0.9 = 1.53 m2

Total = 9.514 m2

This is the minimum area, total carpet required will be higher to allow for matching/fitting etc.

Carpet fitter will initially cut carpet a bit larger the will trim to exact size when fitting

[WILLWONKER]

Thank you also very much for your answer magic, as it will be plain carpet idon't think it will be much more than you say.i