What is the standard thickness of a kitchen worktop?

Stone worktops are usually 20mm or 30mm thick. Laminate and wood worktops are usually around 38–40mm. Ultra-compact surfaces like Dekton also come in 12mm.

Is 20mm quartz strong enough?

Yes. When it's properly supported, 20mm quartz is strong enough for a normal kitchen. Long overhangs need extra support whichever thickness you choose.

Is 30mm worth the extra cost?

If you want a chunkier, more traditional edge, yes. 20mm is usually 10–20% cheaper, and a mitred edge can make 20mm look thicker.

Worktop guide

20mm vs 30mm worktops: does thickness matter?

How worktop thickness affects the look, the strength and the price — and how to choose between them.

The two common thicknesses

Most stone worktops come in 20mm and 30mm. The difference is partly practical and mostly aesthetic. 30mm reads as more solid and traditional; 20mm looks sleeker and more contemporary. Both are strong enough for a normal kitchen when installed correctly.

The look

A 30mm edge gives a chunky, substantial, high-end feel that suits classic and shaker kitchens. A 20mm edge looks lighter and more minimal, which sits well in modern handleless kitchens. Neither is right or wrong — it's about the style you're going for.

Making a thin top look thick

If you want the slim surface of 20mm but the presence of a thick edge, the edge can be “mitred” — a strip is bonded underneath so the visible edge looks 40mm or more while the surface stays thin. It's a popular high-end detail. Equally, a 30mm slab gives you that presence without extra fabrication.

Strength and support

Both thicknesses need proper support underneath, especially over dishwashers, across joins, and on any overhang for breakfast bars. Longer unsupported spans and overhangs may need 30mm or additional support regardless — we'll advise based on your layout when we template.

Quick comparison: 20mm vs 30mm

	20mm	30mm
Look	Slim, modern, minimal	Solid, classic, substantial
Best with	Handleless and contemporary kitchens	Shaker, traditional and farmhouse kitchens
Price	Usually 10–20% cheaper	Uses more stone, so costs a little more
Weight	Lighter, easier on units	Heavier, needs solid support
Overhangs	Shorter unsupported overhangs	Copes with slightly longer overhangs
Thick-edge look	Possible with a mitred edge	Built in

What thickness is a standard kitchen worktop?

In the UK, laminate and wood worktops are usually 38–40mm thick, which is why stone can look slim at first. Stone worktops are normally 20mm or 30mm. Ultra-compact surfaces like Dekton also come thinner, at 12mm, for a very slim, modern profile. If you're replacing a 40mm laminate top, the change in height is easy to deal with at templating, and we'll check your sink, hob and any upstands fit the new thickness.

Thickness by material

Quartz and granite are both widely available in 20mm and 30mm. Marble and quartzite are most often 20mm or 30mm, depending on the slab. Not every colour comes in every thickness, so if you've set your heart on a particular design we'll confirm what's available before you decide.

Islands, breakfast bars and overhangs

For a breakfast-bar overhang, the thickness matters less than the support. As a rule, short overhangs are fine in either thickness, and longer ones need hidden brackets or legs. We'll measure your layout and tell you exactly what's needed at the template visit.

Cost

30mm uses more material, so it typically costs a little more than 20mm in the same design, and a mitred edge adds fabrication labour. The difference is usually modest relative to the whole job. Tell us the look you're after and we'll quote both if it helps you decide.

Thinking about new worktops? We supply and fit quartz, granite and marble from our Sheffield workshop, across South Yorkshire and UK-wide. Get a free quote or call 0114 278 8525.