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What is the difference between 20mm and 40mm stone benchtops?

The number refers to the thickness of the stone slab (porcelain or natural stone). 20mm is the standard (often polished to look thicker via a laminated or mitered edge). 40mm is a thicker, more premium slab — more luxurious appearance.

Do volume builders include 40mm benchtops?

Some premium-positioned builders include 40mm as standard. Most volume builders include 20mm as standard, with 40mm as an upgrade.

How much does upgrading to 40mm cost?

Typically $1,500–$4,000 more than 20mm for a standard kitchen, depending on benchtop size and builder.

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Kitchens

20mm vs 40mm Stone Benchtops

The two most common stone benchtop thicknesses in new homes — which is standard, which is better value, and what builders include.

5 min·Compare My Build — Independent Resource· Updated June 2025

Introduction

Stone benchtop thickness is one of the most visible kitchen specification differences between builder tiers. The 40mm benchtop has become a benchmark for premium kitchen inclusions — but it's far from universal in builder base prices. Understanding what you're getting — and what it costs to upgrade — helps you compare builder packages accurately.

Feature	20mm Stone	40mm Stone
Thickness	20mm	40mm
Appearance	Standard / slim	Chunky / premium
Edge profile options	More limited (thin edge)	Wider range including waterfall
Standard inclusion	Most volume builders	Some premium builders
Upgrade cost	—	+$1,500 – $4,000
Structural difference	Same material strength	Same — purely aesthetic
Popularity	Very common	Growing — becoming an expectation

Cost Comparison

20mm porcelain or natural stone benchtop (standard)Included

40mm stone upgrade+$1,500 – $4,000

40mm benchtop with waterfall edge+$3,000 – $7,000

Costs depend on benchtop size, stone type and builder. Confirm exact specification in your contract.

Common Builder Inclusions

›20mm stone benchtops are standard with most volume builders
›40mm stone is offered as an upgrade or included in premium builder packages
›Some builders include 40mm as a promotional inclusion — confirm it's in writing
›Edge profiles vary — confirm if a waterfall or bullnose edge is included with 40mm
›Ask: 'Is the benchtop 20mm or 40mm? What edge profile is included?'

Common Trap

A builder advertising '40mm stone benchtops' may only include them on the kitchen island — not all benchtop runs. Always clarify whether 40mm applies to all benchtop surfaces or just select areas.