How to Measure the Location of a Sink or Hob Cutout on a Kitchen Worktop

Last Updated on May 21, 2026

If your kitchen cabinets are installed and you’re preparing for a sink cutout in your worktop, accuracy is key. Here’s a step-by-step guide to help you measure everything correctly:

1. Identify the Sink Cabinet

Locate the cabinet where the sink will be installed — this is typically one of the widest base cabinets in the kitchen, designed specifically to accommodate a sink and the plumbing underneath.

Here’s what you should know about sink cabinets:

• Width options:
  Sink cabinets commonly come in 600mm, 800mm, or 1000mm widths.
  
  • 600mm is often used for compact single-bowl sinks.
    
  • 800mm is a popular middle-ground size that fits most single-bowl or 1.5-bowl sinks.
    
  • 1000mm is often chosen for large 1.5 or double-bowl sinks.
    
• No top rails:
  Unlike other cabinets, sink base units typically have no horizontal rail or panel at the top. This open-top design makes it easier to drop the sink in from above.
  
• Open back or partial back:
  Sink cabinets often have an open back (or a partial cutout) to allow access to water pipes and waste lines.
  
• Positioning:
  Sink cabinets are usually placed centrally under a window or near the plumbing stack, making it easy to align your cutout with existing plumbing.

Knowing exactly which cabinet is the sink base — and confirming its external width — is crucial before marking or measuring your sink cutout.

2. Find the Center of the Sink Cabinet

• Measure the full external width and length of the sink cabinet — from the outside edge of one side panel to the outside edge of the other (i.e. not the internal space, but the total cabinet width including the thickness of the particle board).
  
• Divide that measurement by two to find the exact center along the length (left to right) of the cabinet.
  
• Do the same to find the center along the width (front to back) of the cabinet.
  
• You now have the center point across both dimensions — length and width.
  
• Mark this center point on all four panels (left, right, front, and back). This ensures clarity and consistency from any angle, especially when laying the worktop down or transferring measurements.

This marked center will act as your main reference when aligning the sink cutout.

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3. Measure From the Sink Cabinet Center to the Ends of the Cabinet

Measure from the center point of the sink cabinet outward — in all four directions: left, right, front, and back. These distances will help you position the sink cutout within the worktop accurately.

🡐 Left Side

• If the worktop ends at a wall:
  Measure from the center of the sink cabinet to the wall.
  Then subtract 5mm to allow for an expansion gap.
  This gap will later be covered by a splashback, tiles, or an upstand.
  
  Example: 1460mm to wall → 1460 – 5 = 1455mm
  
• If the worktop ends at a cabinet:
  Measure from the center of the sink cabinet to the external edge of the last cabinet.
  
  Then add your desired overhang:
  
  • Flush: +0mm
    
  • Minimal overhang: +5mm
    
  • Standard overhang: +20mm

• Example: 1350mm to cabinet → 1350 + 20 = 1370mm

Repeat the same logic:

• To a wall? Subtract 5mm.
  
• To a cabinet? Add the overhang.

Figure 2: Measuring the center of the cabinet and the distances to all 4 sides.

⬍ Front to Back

• Back (towards the wall):
  Measure from the sink cabinet center to the wall.
  Then subtract 3–5mm for the expansion gap.
  This gap will be hidden by the wall finish — splashback, tiles, or upstand.
  
• Front (towards room):
  Measure to the outer edge of the cabinet.
  Then add your desired overhang — typically 20mm for standard kitchens, unless going for a flush finish.

4. Calculate the Total Worktop Size (Length & Width)

Now that you’ve measured from the center of the sink cabinet to each end, it’s time to calculate the total worktop size you’ll need.

🡐🡒 Total Length (Left to Right)

• Add the distance from the cabinet center to the left end and the distance from the center to the right end.
  
  Example:
  • Left side: 1455mm
    
  • Right side: 1370mm
    
    → Total Length = 1455 + 1370 = 2825mm

This is the full length of your worktop.

⬍ Total Depth (Front to Back)

In a similar logic to the length calculation, simply add the distance from the cabinet center to the front end and the distance from the center to the back end.

Example Calculation:

• Center to front edge of cabinet: 300mm
  
• Front overhang: +20mm
  → Front total = 320mm
  
• Center to back wall: 305mm
  
• Expansion gap: –5mm
  → Back total = 300mm

→ Total Worktop Depth = 320mm + 280mm = 620mm

By calculating the total length and depth, you now have the exact size your worktop should be cut to — before you even begin marking the sink cutout.

Worktop Size = 2825mm x 620mm x Thickness

5. Check Your Sink Cutout Dimensions

Now we will be mapping out the sink dimensions on top of your existing worktop size. We will be working outwards from the sink cabinet once again.

Firstly, to find out what the size of the sink cutout (not the sink itself!) you can refer to the manufacturer’s specification sheet for your specific sink. Every sink model comes with its own cutout size — these are typically shown as a diagram in the product’s documentation or downloadable PDF.

Here’s what to look for:

• Length (left to right): e.g. 500mmWidth (front to back): e.g. 400mm
  
• Note: Those are not the dimensions of your sink cutout. Those are example numbers.

Here’s what to look for:

• Length (left to right): e.g. 500mmWidth (front to back): e.g. 400mm
  
• Note: Those are not the dimensions of your sink cutout. Those are example numbers.

These measurements tell you the exact size of the opening that needs to be made in the worktop to fit the sink. The actual sink will slightly overhang this opening to rest securely on the surface (or clip underneath, in the case of undermount sinks).

⚠️ Important: These measurements should always come from the official spec sheet included with your sink or found online via the manufacturer’s website. They can also be calculated manually.

🔄 Pay Attention to Internal Radius Corners

For undermounted sinks and Belfast (butler) sinks, the corner radius of the cutout is important for a seamless and matching look.

• Internal radius refers to the rounded corners of the cutout.
  
• Most undermount sinks require rounded internal corners (often R10, R15, R20, etc.), which must be matched precisely during cutting.

⚠️ If your sink requires rounded corners and you cut sharp 90° angles, it might affect the aesthetic look of the sink and can affect the positioning of the sink.

Always match the radius of the cutout to the specifications — or consult your fabricator if unsure.

6. Position the Sink Cutout

Now that you’ve determined your full worktop dimensions and the size of your sink cutout, it’s time to position the cutout precisely on the worktop.

📝 Sink Cutout Dimensions (from previous step):

Cutout Length (left to right): 500mm
Now divide the length and the width by 2 to find the half.
→ Half of length: 500 / 2 = 250mm

Cutout Width (front to back): 400mm
→ Half of width: 400 / 2 = 200mm

Your goal is to align the center of the sink cutout with the marked center of your sink cabinet, and then calculate its distance from the edges of the worktop.

You’ll work out the position of the cutout relative to:

1. Left edge of the worktop
   
2. Right edge of the worktop
   
3. Front edge of the worktop

Figure 2: Aligning the centers of the sink cutout and the sink cabinet.

📍 Distance from the Right Edge of the Worktop

We already know:

• Distance from the center of the sink cabinet to the right edge of the worktop = 1455mm
  
• Half of the sink cutout length = 250mm

So:

Distance from right edge of the worktop to the edge of cutout
= 1455mm – 250mm
= 1205mm

📍 Distance from the Left Edge of the Worktop

We also know:

• Distance from the center of the sink cabinet to the left edge of the worktop = 1370mm
  
• Half of the sink cutout length = 250mm

So:

Distance from left edge to center of cutout
= 1370mm – 250mm
= 1120mm

📍 Distance from the Front Edge of the Worktop

We already know:

• Distance from the center of the sink cabinet to the front edge of the worktop = 320mm
  
• Half of the sink cutout width = 200mm

Distance from front worktop edge to edge of cutout
= 320mm – 200mm = 120mm

Figure 3: Calculating the distances of the cutout from the left, right and front edge.

7. Measuring for L-Shaped or U-Shaped Kitchens

(When Worktops Run Into One Another)

In corner kitchen layouts, it’s common to have one worktop that runs all the way to a wall, and another that joins into it at a straight joint. Knowing how to handle each type correctly is essential for accurate sink cutout positioning.

Figure 4: Type 1 and Type 2 Worktop for an L or U-Shape Kitchen.

Type 1: Worktop Runs to a Wall

Use the same method as described earlier in the guide:

1. Measure from the center of the sink cabinet to each end of the worktop.
   
2. Subtract 5mm from any side that ends at a wall for an expansion gap.
   
3. Add overhangs where necessary (e.g., 20mm at the front or open edge).
   
4. Use these measurements to calculate the position of the sink cutout — just like in a standard straight run and as described in the steps from 1 to 6.

Type 2: Worktop Joins Another Worktop (Straight Joint)

This applies when your sink is installed on a worktop that joins into another (i.e., does not end at a wall).

Here’s how to measure:

1. Measure from the center of the sink cabinet to the wall behind the worktop it’s joining into.
   (Yes — we know there’s another worktop between — just bear with us.)
   
2. Subtract the 5mm expansion gap at the wall.
   
3. Subtract the width of the adjoining worktop (from Type 1).
   This gives you the true distance from the sink cabinet center to the edge of your own worktop.

📐 Example:

• Distance from sink cabinet center to wall: 1385mm
  
• Expansion gap: 5mm
  
• Width of Type 1 worktop: 620mm

Result:
1385 – 5 – 620 = 760mm
→ That’s your measurement from the center of the sink cabinet to the edge of your worktop.

✅ Final Step: Prepare and Share Your Drawing

Now that you’ve taken all the necessary measurements and calculated every position, it’s time to put everything into one clear drawing — with all dimensions marked.

📐 Your Drawing Should Include:

• Total worktop length and width
  
• Exact position of the sink cutout (distances from left, right and front)
  
• Exact dimensions of the sink cutout with any internal radius corners if any.
  
• Special details: beveled edges, radius corners, sink type (undermount, Belfast, etc.)

Once you’ve got it all sketched out:
📤 Send the drawing to your worktop supplier.

With these dimensions, your supplier can:

• Pre-cut your sink or hob cutout
  
• Pre-cut your draining grooves (if needed)
  
• Prepare joint positions
  
• Apply edge profiling
  
• And even cut tap holes on request

💪 This puts you in full control while still taking advantage of professional finishing — it’s the perfect hybrid between DIY and custom manufacturing.