Countertop Thickness Chart 2026: Inches to Millimetres

How thick is a countertop?

Countertop thickness is measured in inches in the US and in millimetres (or centimetres) everywhere else — 1 inch = 25.4 mm exactly. Stone slabs are sold by centimetre: 2 cm stone is about 0.79 inches, 3 cm stone is about 1.18 inches, 4 cm stone is about 1.57 inches, 6 cm stone is about 2.36 inches, 8 cm stone is about 3.15 inches. The most common kitchen countertop is 3 cm stone (about 1.18 inches, sold as 30 mm) or a standard 1.25-inch quartz. Laminate counters are usually 1 inch thick or thinner; butcher block runs 1.25–1.5 inches; mitered edges stack two slabs to look 2 inches or thicker without the weight.

Two things about the model are worth stating plainly. First, the thickness in millimetres is the thickness in inches times 25.4 — 1.25 × 25.4 = 31.75 mm. Second, the matching types are every countertop type whose thickness range contains your thickness — at 1.25 inches that is four types: butcher block, standard laminate, 3 cm stone and standard stone / quartz; all listed in Accuracy & limitations.

The countertop thickness chart

Three thicknesses appear more than once in the chart — 1.25 inches is shared by the standard stone / quartz row and the 3 cm stone range, 2.50 inches is shared by the thick mitered row and the 6 cm stone range, and 3.15 inches is shared by the thick mitered range, the extra-thick island / waterfall range and the 8 cm stone row. The thinnest standard thickness is the 0.50-inch thin laminate overlay at 12.70 mm, and the thickest is the 3.15-inch 8 cm stone at 80.01 mm.

The worked example, line by line

Setup: 1.25-inch thickness.

Line 1 — the thickness in millimetres. The thickness in millimetres is 1.25 × 25.4 = 31.75 mm.

Line 2 — the matching types. The countertop types whose thickness range contains 1.25 inches are the butcher block, standard laminate, 3 cm stone and standard stone / quartz — four types.

Line 3 — the switch from standard to thick. Switching from a 1.25-inch standard thickness to a 3.15-inch 8 cm stone raises the countertop by 1.90 inches — 48.26 mm.

Line 4 — the check. 1.25 × 25.4 = 31.75 mm, the thickness; and 3.15 − 1.25 = 1.90 inches, the rise.

Every branch, checked

Thickness 0.75 in: Height 0.75 in; 19.05 mm; matching types: thin laminate overlay, butcher block — At 0.75 inches the thickness is 19.05 mm and matches the thin laminate overlay and the butcher block.

Thickness 1.00 in: Height 1 in; 25.40 mm; matching types: butcher block, standard laminate — At 1.00 inch the thickness is 25.40 mm and matches the butcher block and the standard laminate.

Thickness 1.50 in: Height 1.5 in; 38.10 mm; matching types: butcher block, standard stone / quartz, thick butcher block / mitered edge — At 1.50 inches the thickness is 38.10 mm and matches the butcher block, the standard stone / quartz and the thick butcher block / mitered edge.

Thickness 2.00 in: Height 2 in; 50.80 mm; matching types: thick butcher block / mitered edge, double-stacked / mitered — At 2.00 inches the thickness is 50.80 mm and matches the thick butcher block / mitered edge and the double-stacked / mitered.

Thickness 2.50 in: Height 2.5 in; 63.50 mm; matching types: double-stacked / mitered, 6 cm stone, thick mitered, extra-thick island / waterfall — At 2.50 inches the thickness is 63.50 mm and matches the double-stacked / mitered, the 6 cm stone, the thick mitered and the extra-thick island / waterfall.

Thickness 3.15 in: Height 3.15 in; 80.01 mm; matching types: thick mitered, extra-thick island / waterfall, 8 cm stone — At 3.15 inches the thickness is 80.01 mm and matches the thick mitered, the extra-thick island / waterfall and the 8 cm stone.

Thickness 0.50 in: Height 0.5 in; 12.70 mm; matching types: thin laminate overlay — At 0.50 inches the thickness is 12.70 mm and matches the thin laminate overlay only.

The reverses, worked backwards

Smallest thickness (to the hundredth) for the millimetre figure to reach 30.00 mm: At the displayed 1.19 in the figures are Height 1.19 in; 30.23 mm (unrounded 30.226 mm); matching types: butcher block, standard laminate, 3 cm stone. At the displayed 1.19 in the thickness is 30.23 mm. At 1.18 in the thickness is 29.97 mm — below 30.00 — so 1.19 in is the smallest thickness (to the hundredth) for the millimetre figure to reach 30.00 mm.

Largest thickness (to the hundredth) for the millimetre figure to STAY at or below 40.00 mm: At the displayed 1.57 in the figures are Height 1.57 in; 39.88 mm (unrounded 39.878 mm); matching types: thick butcher block / mitered edge, 4 cm stone. At the displayed 1.57 in the thickness is 39.88 mm. At 1.58 in the thickness is 40.13 mm — above 40.00 — so 1.57 in is the largest thickness (to the hundredth) for the millimetre figure to stay at or below 40.00 mm.

Smallest thickness (to the hundredth) for the millimetre figure to reach 50.00 mm: At the displayed 1.97 in the figures are Height 1.97 in; 50.04 mm (unrounded 50.038 mm); matching types: thick butcher block / mitered edge. At the displayed 1.97 in the thickness is 50.04 mm. At 1.96 in the thickness is 49.78 mm — below 50.00 — so 1.97 in is the smallest thickness (to the hundredth) for the millimetre figure to reach 50.00 mm.

Smallest thickness (to the hundredth) to match 4 cm stone: At the displayed 1.57 in the figures are Height 1.57 in; 39.88 mm (unrounded 39.878 mm); matching types: thick butcher block / mitered edge, 4 cm stone. At the displayed 1.57 in the thickness is 39.88 mm and it matches 4 cm stone. At 1.56 in it does not match 4 cm stone — so 1.57 in is the smallest thickness (to the hundredth) to match 4 cm stone.

Largest thickness (to the hundredth) to still match standard laminate: At the displayed 1.25 in the figures are Height 1.25 in; 31.75 mm; matching types: butcher block, standard laminate, 3 cm stone, standard stone / quartz. At the displayed 1.25 in the thickness is 31.75 mm and it matches standard laminate. At 1.26 in the thickness is 32.00 mm and it no longer matches standard laminate (it still matches butcher block and standard stone / quartz) — so 1.25 in is the largest thickness (to the hundredth) to still match standard laminate.

Smallest thickness (to the hundredth) to match 6 cm stone: At the displayed 2.36 in the figures are Height 2.36 in; 59.94 mm (unrounded 59.944 mm); matching types: double-stacked / mitered, 6 cm stone. At the displayed 2.36 in the thickness is 59.94 mm and it matches 6 cm stone. At 2.35 in it does not match 6 cm stone — so 2.36 in is the smallest thickness (to the hundredth) to match 6 cm stone.

What the defaults assume

The defaults are a 1.25-inch thickness — Height 1.25 in; 31.75 mm; matching types: butcher block, standard laminate, 3 cm stone, standard stone / quartz. With Thickness 0.75 in, Height 0.75 in; 19.05 mm; matching types: thin laminate overlay, butcher block. With Thickness 1.00 in, Height 1 in; 25.40 mm; matching types: butcher block, standard laminate. With Thickness 1.50 in, Height 1.5 in; 38.10 mm; matching types: butcher block, standard stone / quartz, thick butcher block / mitered edge. With Thickness 2.00 in, Height 2 in; 50.80 mm; matching types: thick butcher block / mitered edge, double-stacked / mitered. With Thickness 2.50 in, Height 2.5 in; 63.50 mm; matching types: double-stacked / mitered, 6 cm stone, thick mitered, extra-thick island / waterfall. With Thickness 3.15 in, Height 3.15 in; 80.01 mm; matching types: thick mitered, extra-thick island / waterfall, 8 cm stone. With Thickness 0.50 in, Height 0.5 in; 12.70 mm; matching types: thin laminate overlay. With Thickness 0 in, Height 0 in; 0.00 mm; matching types: no matching type. With Thickness −5 in (floored to 0), Height 0 in; 0.00 mm; matching types: no matching type. With Thickness 0.59 in, Height 0.59 in; 14.99 mm (unrounded 14.986 mm); matching types: thin laminate overlay. With Thickness 1.1811 in, Height 1.1811 in; 30.00 mm (unrounded 29.99994 mm); matching types: butcher block, standard laminate, 3 cm stone. With Thickness 3.15 in, Height 3.15 in; 80.01 mm; matching types: thick mitered, extra-thick island / waterfall, 8 cm stone. With Thickness 2.99 in, Height 2.99 in; 75.95 mm (unrounded 75.946 mm); matching types: thick mitered, extra-thick island / waterfall. With Millimetre bars, 1.00 in = 25.40 mm; 2.00 in = 50.80 mm; 3.00 in = 76.20 mm.

A note on the rounding: at 0.59 inches the unrounded millimetre figure is 14.986 mm, which rounds half-up to 14.99 mm; at 1.1811 inches the unrounded millimetre figure is 29.99994 mm, which rounds to 30.00 mm; at 2.99 inches the unrounded millimetre figure is 75.946 mm, which rounds to 75.95 mm. The page prints the unrounded values so the rounding does not mislead you. A negative thickness input is floored at 0 — it shows 0.00 mm and no matching type, never a negative number.

Output · formula · meaning

Who uses this

• The homeowner buying a standard stone countertop: they learn a standard stone countertop is 1.25 inches thick — 31.75 mm — and they check the 1.19 in reverse to see the smallest thickness that reaches 30.00 mm.
• The homeowner buying a 6 cm stone island: they learn 6 cm stone is about 2.36 inches — 59.94 mm — and they check the 2.36 in reverse to see the smallest thickness that matches 6 cm stone.
• The homeowner with a 2.50-inch alcove: they learn it is 63.50 mm and matches the double-stacked / mitered, the 6 cm stone, the thick mitered and the extra-thick island / waterfall — and they check the 1.57 in reverse to see the smallest thickness that matches 4 cm stone.
• The homeowner with a 0.59-inch reading: they learn it is 14.99 mm — the unrounded figure is 14.986 mm — and they check the 1.25 in reverse to see the largest thickness that still matches standard laminate.

Accuracy & limitations

The math is first-principles: the thickness in millimetres is the thickness in inches times 25.4, rounded to two decimals half-up; the matching types are the countertop types whose thickness range contains your thickness; the thickness in inches is floored at 0 — a negative thickness input shows 0.00 mm and no matching type, never a negative number. The reverses are judged on the UNROUNDED millimetre figure: at 1.1811 in the thickness is 29.99994 mm unrounded, which rounds to 30.00 mm, so it reaches the 30.00 mm target; at 1.18 in the thickness is 29.972 mm unrounded, which rounds to 29.97 mm, so it does not. What the model cannot do is set your countertop thickness: the thicknesses in the table are the standard figures, not a rule for every countertop — when a supplier quotes “3 cm”, the finished slab is usually 29–30 mm after polishing, not exactly 30 mm; a 3 cm slab weighs about 50% more than a 2 cm slab, so cabinets and supports matter; and very thick tops cost more per square foot. Use it to find the millimetre figure and the matching types for your thickness — then measure twice before you buy.

Frequently asked questions