How to Cut a Quartz Countertop Kitchen Sink Hole


Installing a sink into a quartz countertop can seem daunting, but with the right tools and techniques, it’s very achievable as a DIY project. Quartz is an engineered stone made from crushed quartz combined with resins and pigments, making it an extremely durable and low-maintenance countertop material. However, it does require specialized cutting tools and methods to cut clean holes for sinks. This guide will walk through everything you need to know to successfully cut a hole in your quartz countertop for installing a kitchen sink.

What You’ll Need

  • Tape measure
  • Pencil
  • Straightedge
  • Router with 1/4″ carbide bit
  • Diamond grit hole saw kit for quartz
  • Sandpaper
  • Eye and ear protection
  • Dust mask
  • Gloves
  • Clamps
  • Clean rags

How to Measure and Mark the Sink Cutout

The first step is using a tape measure to find the exact position for the sink cutout and mark the hole location.

  • Place the sink upside down on the countertop where you want to install it. Make sure the sink is centered side-to-side on the countertop.
  • Trace along the edge of the sink with a pencil to mark the cutout outline.
  • Remove the sink and measure the cutout dimensions. Make sure to account for any rim or lip around the sink edge.
  • Use a straightedge to mark straight lines and square corners for the cutout rectangle.
  • Mark the depth of the sink rim or lip, if any, measuring down from the outline to extend the cutout depth.

Be as precise as possible at this stage – any errors will be difficult to correct later. Double check all measurements before proceeding.

How to Cut the Sink Hole

With the outline marked, it’s time to start cutting. This requires patience and care to get clean cuts in the hard quartz material.

Step 1: Drill Holes for Router Bit Access

  • Put on all safety gear – eye protection, dust mask, ear protection, gloves.
  • Use a carbide-tipped masonry drill bit to drill 1″ diameter holes just inside each corner of the cutout outline.
  • Drill slowly to avoid cracking the quartz. Let the bit do the work.
  • These access holes allow inserting the router bit into the cutout.

Step 2: Rough Cut with Router

  • Fit the router with a 1/4″ carbide bit.
  • Carefully insert the spinning router bit into one access hole, letting it gradually engage the quartz.
  • Slowly guide the router bit along the cutout line to complete the cut between access holes.
  • Repeat for the remaining sides, working clockwise or counter-clockwise.
  • Make relief cuts at the corners to allow the bit to turn. Go slowly!

Step 3: Smooth and Refine Edges

  • Switch to a diamond grit quartz hole saw kit, using the supplied grit to smooth and shape the cut edges.
  • Use the cone-shaped grit attachments to refine corners and curve profiles.
  • Finish by hand-sanding for a polished edge. Use 100-220 grit sandpaper.
  • Visually inspect edges for any remaining bumps or ridges and sand smooth.
  • Clean away all dust.

How to Install the Sink

Once the cutout is finished, dry fit the sink to test the fit. The sink should drop into place flush with the top.

  • Clean the bottom of the sink and underside of the countertop with denatured alcohol.
  • Apply silicone adhesive caulk around the top edges of the sink.
  • Carefully lower the sink in place, aligning with the cutout.
  • From underneath, secure mounting brackets or clips to hold the sink snugly.
  • Allow the caulk to fully cure for 24-48 hours before using the sink.

That’s it! Take your time with each step and you’ll have a beautifully installed quartz countertop sink. Pat yourself on the back for taking on a challenging DIY project and doing it right. Enjoy your updated kitchen!

Frequently Asked Questions

How deep should the sink cutout be in a quartz countertop?

The cutout depth depends on the sink model, but generally should allow the rim to rest flush on the countertop surface. Measure the sink depth from the bottom to the rim lip to determine how deep to cut.

Can I cut a sink hole in quartz with a jigsaw?

It’s not recommended. A jigsaw often chips and cracks the quartz. A router and diamond hole saws are specially designed to cut quartz cleanly.

What size bit do I need to drill holes for router access?

Use a 1″ diameter carbide-tipped masonry drill bit to drill the corner holes that allow inserting the router bit.

Should I use a template for the sink cutout?

Yes, make a cardboard or hardboard template from the exact sink dimensions to trace onto the countertop. This ensures accurate sizing.

How can I finish the edges of the cutout smoothly?

Use a diamond grit hole saw kit made for quartz to refine and smooth the cut edges after routing. Hand sanding helps polish the edges too.


Cutting a hole for an undermount kitchen sink in a quartz countertop is definitely a DIY project you can tackle yourself with the right preparation. Have patience, use the proper quartz cutting tools, and protect the work area from dust. Measure twice, cut once. When done correctly, you’ll have a beautiful custom sink installation that perfectly fits your countertop and kitchen.