Kitchen Worktop Calculator — Lengths, Joints & Cut-Outs

The standard UK kitchen worktop depth is 600mm, which aligns with standard base unit depths of 570mm plus a small overhang. Deeper worktops of 650mm or 900mm are available for breakfast bars or island units. Most laminate worktops from UK suppliers like Howdens, Wickes, and B&Q come in 600mm depth as standard.

UK laminate worktop slabs are stocked at 3.0m, 3.6m and 4.1m (Worktop Express, Howdens and Wickes all list these lengths). This calculator counts slabs and joints against the common 3.6m length, so a run up to 3.6m needs only one board. Solid surface and quartz worktops are usually templated and cut to exact measurements. For runs longer than a single slab, joints are made using worktop bolts (typically 150mm bolts with biscuit joints) and colour-matched sealant.

Each corner in an L-shape or U-shape kitchen requires one mason’s mitre joint. An additional joint is needed if any straight run exceeds the 3.6m stock slab length. Joints should be positioned away from the sink and hob where possible, and mason’s mitre joints are standard for laminate worktops.

Sink cut-outs vary by model but typical undermount sinks need a cut-out of approximately 480mm x 380mm for a single bowl or 810mm x 380mm for a 1.5 bowl. Always follow the manufacturer template. Inset sinks sit in a larger hole with a lip that covers the cut edge. Allow at least 50mm from the front edge of the worktop to the cut-out.

Upstands (typically 100mm high matching worktop material) provide a seal between the worktop and wall. They are cheaper than tiled splashbacks but less protective. Building Regulations do not mandate splashbacks, but they are recommended behind hobs. Many fitters install upstands everywhere except behind the hob where a full splashback or glass panel is fitted.