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Why countertop area decides the price
Countertops are priced by area, cut from slabs, and ordered in square feet or square metres. A wrong area means a wrong quote, a slab that does not fit, or a shortfall discovered on installation day. This calculator gives the area for the two shapes that cover nearly every kitchen: a straight run, and an L-shape with two runs meeting at a corner. It reports both square metres and square feet, because stone yards and kitchen suppliers often quote in different units, and converting by hand is where errors creep in.
The straight case is simple multiplication. A run 3 metres long and 0.6 metres deep covers 1.8 square metres, which is about 19.4 square feet. The L-shape needs one careful step: the corner square belongs to both runs, so it must be counted once, not twice. A main run of 3 by 0.6 metres is 1.8 square metres, a second run of 2 by 0.6 metres is 1.2, and the shared corner of 0.6 by 0.6 is 0.36. Add the two runs and subtract the corner once: 1.8 plus 1.2 minus 0.36 gives 2.64 square metres, about 28.4 square feet. Forgetting that subtraction overstates the area by more than a tenth, and on stone prices that is real money.
How to use the calculator
- Choose the shape: straight run, or L-shaped.
- Enter the main run length and depth in metres.
- For an L-shape, enter the second run length and depth too.
- Read the area in square metres and square feet, and use it for quotes and slab planning.
A worked example
Take a straight kitchen run 4 metres long and 0.65 metres deep, a common depth for a run with a raised splash. Four times 0.65 is 2.6 square metres, about 28 square feet. Now take a small L-shaped kitchen: main run 3 metres by 0.6, second run 2 metres by 0.6. As above, the answer is 2.64 square metres. If a supplier quotes 60 per square foot, the straight run costs about 1,680 and the L-shape about 1,704 in the same units, which shows why the corner correction matters: counting the corner twice would add over 200 to the L-shape quote for stone that does not exist.
Depth deserves attention. Standard counter depth is about 0.6 metres, but runs with sinks, hobs or breakfast bars vary. Measure the real depth, including any overhang, because the stone is cut to the full depth, not to the cabinet depth. Measure length wall to wall, and decide how corners and joins will be handled with the supplier before ordering, since a two-slab job may need a seam that a single area figure does not show.
Tips for measuring countertops
- Measure twice, at the wall and at the front edge, since walls are rarely straight.
- Include overhangs: an island or breakfast bar overhang adds area and needs support.
- Note sink and hob cutouts separately. They reduce stone used but rarely reduce the price.
- Ask the supplier whether the quote is per square foot of slab or per square foot installed.
- Keep a sketch with every measurement labelled, and photograph it for the supplier.
Common mistakes
The most common mistake is counting the L-shape corner twice, which inflates the quote. The second is measuring cabinet depth instead of counter depth, which understates the area and leaves the front edge short. The third is mixing units: entering feet into a metres calculator, or quoting square feet from a metres measurement without converting. This calculator reports both units precisely to prevent that. The fourth is forgetting splashbacks, upstands and islands, which are separate areas. Remember that this tool is an educational estimator for area only. It does not price stone, allow for cutouts, seams, edge profiles or installation, and it does not judge whether a span needs support. Those questions belong to the supplier and, for structural spans, a professional.
Who measures countertops
Kitchen fitters measure before quoting, homeowners measure before comparing stone suppliers, and renovators measure when checking whether a quoted price matches their kitchen. Area is the shared language of the whole job. Measure the runs, pick the shape, and the calculator gives the figure every quote should be based on.
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