The cut-out size is what decides whether a kitchen sink fits. It is not the size printed in the product title, and the two are never the same number. Across the sinks below, the cut-out runs 20mm to 60mm narrower than the body.
Every figure here comes from a live ThatRenoStore listing.
Single bowl or double bowl?
Pick a single bowl for the largest usable washing area in a given counter width. Pick a double bowl if you wash on one side and stack or rinse on the other.
The NOBEL NU-12-SS is a double bowl at 780 x 430 x 230mm overall, split into a 385 x 380mm bowl and a 320 x 330mm bowl. The NU-13-SS is a single bowl at 680 x 450 x 230mm overall, with a main bowl of 630 x 400mm.
So the narrower sink gives you the bigger single space. The wider double-bowl unit still tops out at a 385mm bowl. That is the number to hold a wok or an oven tray against before you decide.
Other double-bowl options include the QNTL-K8245 at 820 x 450mm in chrome. Compact single bowls go down to the G.Ferretti GKRS 450 at 450 x 450 x 230mm.
Overall size vs cut-out size
The overall size is the outside of the sink. The cut-out size is the hole in the countertop. Your fabricator works to the cut-out figure. Cut to the overall figure instead and the hole is too wide for the sink to sit on, which is not something you fix in a granite worktop.
The gap between the two is not consistent across brands, or even within one brand.
| Model | Overall size | Cut-out size | Difference |
|---|---|---|---|
| Aalto AT5042 | 500 x 420 x 190mm | 480 x 400mm | 20mm |
| Aalto AT8050B | 800 x 500 x 230mm | 775 x 475mm | 25mm |
| Aalto AT8349 | 838 x 498 x 220mm | 810 x 470mm | 28mm |
| Aalto AT8245L | 820 x 450 x 225mm | 790 x 420mm | 30mm |
| Aalto AT5843 | 580 x 430 x 215mm | 530 x 380mm | 50mm |
| G.Ferretti GKRS 450 | 450 x 450 x 230mm | 400 x 400mm | 50mm |
| G.Ferretti GKRS 680 | 680 x 450 x 230mm | 630 x 400mm | 50mm |
| Aalto AT6046 | 600 x 460 x 200mm | 540 x 400mm | 60mm |
The AT5843 undermount sink is a clean example: a 580 x 430 x 215mm body sitting in a 530 x 380mm cut-out, 304 stainless at 1.2mm, straight brush finish. Fifty millimetres of that width is rim.
One more label to watch. NOBEL listings quote a bowl size. G.Ferretti and Aalto listings quote a cut-out size. Those describe different things. The NU-13-SS main bowl is 630 x 400mm. The GKRS 680 cut-out is 630 x 400mm. Same numbers, same 680 x 450 x 230mm body, two measurements that are not interchangeable. A bowl figure is the inside of the sink. Take the cut-out figure to your fabricator.
The same distinction applies to inset basins, which is covered in the basin buying guide.
What the thickness number is describing
Thickness on these listings refers to the 304 stainless steel. The Aalto AT5042 and AT6046 quote 1.0mm. The AT5843 and the G.Ferretti GKRS range quote 1.2mm. The NOBEL NU-12-SS, NU-13-SS and NU-15-SS quote 3.5mm.
Read the full listing before you take a thickness figure at face value. The G.Ferretti GKSB range carries "border edging is 3mm thickness" in the product title, which is describing the edging. The listing body quotes the material thickness separately, and it is not always the same figure: the GKSB 600 MGun body quotes 3mm, while the GKSB 600 Silver body quotes 1.2mm. Check the body of the specific model you are looking at.
Before you order
- Measure your existing cut-out, not your existing sink.
- Match the cut-out figure on the listing to that measurement.
- Check whether the listing is quoting a bowl size or a cut-out size.
- Check the depth against your cabinet and waste pipe. Most sinks here sit between 190mm and 230mm.
- Check whether you need a tap hole. Some models are sold as tap-hole versions, such as the GKSB 600T and GKSB 800T.
If a toilet bowl is going in during the same renovation, the same measure-first discipline applies there: see how to check your S-trap or P-trap roughing-in before ordering.
FAQ
What cut-out size do I need for a kitchen sink?
The cut-out size is stated on the product listing and is smaller than the sink's overall size. On the sinks compared here it runs 20mm to 60mm narrower. Work to the listed cut-out figure, never the overall dimensions.
Is a double bowl better than a single bowl?
Neither is better in the abstract. It comes down to counter width. A double bowl splits the space, so each bowl is smaller: the NU-12-SS is 780mm wide with a largest bowl of 385mm, while the 680mm-wide NU-13-SS has one 630mm bowl.
What do the thickness numbers on a kitchen sink listing mean?
They refer to the 304 stainless steel used. Listings in this range quote 1.0mm, 1.2mm and 3.5mm. On the GKSB range, the 3mm figure in the product title refers to the border edging, so check the listing body for that model's material thickness.
Can I replace a sink without changing the countertop?
Only if the new sink's cut-out size matches your existing hole. A hole can be enlarged but not easily made smaller, so a sink needing a smaller cut-out than your current hole is the harder swap.