How to measure under sink cabinets properly (before you buy organisers)
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Under sink storage usually fails for one simple reason: people buy organisers before they measure properly.
Unlike a normal cupboard, under-sink cabinets have pipes, sink bowls, hinges and door lips that quietly eat into usable space. What looks fine on paper often doesn’t work in real life, which is why so many organisers end up returned or shoved awkwardly to one side.
This guide walks through exactly what to measure, in the right order, so you can choose an organiser that actually fits and works long-term.
Why under sink cabinets are tricky to measure
Under-sink cupboards aren’t empty boxes. They usually include:
- Plumbing that cuts through the middle or runs along the back
- Sink bowls that hang lower than expected
- Door hinges that steal internal width
- Fixed shelves or lips at the cabinet opening
- Filters or disposal units that reduce usable height
Because of this, usable space is often very different from the cabinet’s overall size. Measuring properly upfront saves frustration later.
Tools you’ll need
Nothing fancy.
- A tape measure
- A torch or phone light
- Pen and paper (or notes app)
- Optional: cardboard to mock up shelf size
Before you start, remove everything from the cupboard so you’re measuring the space, not the clutter.
Step 1 – Measure the internal width
Measure from inside wall to inside wall, not the outside of the cabinet.
Things to watch for:
- Hinges often reduce usable width near the front
- Some cabinets are narrower at the back than the front
Tip:
Measure the width at the narrowest point, not just the widest. That’s the number that matters when buying organisers.
Step 2 – Measure the usable depth
Depth is more than just front to back.
Measure:
- From the inside front edge (past any door lip)
- To the back wall or the furthest pipe
Why this matters:
Some organisers are deeper than the cabinet opening, which means drawers won’t pull out properly or shelves won’t sit flat.
Always measure usable depth, not total depth.
Step 3 – Measure the usable height
Height is where most people get caught out.
Measure:
- From the cabinet floor
- To the lowest obstruction (sink bowl or pipe)
In bathrooms especially, the sink bowl often sits lower than expected, limiting what you can stack underneath.
If you’re planning a two-tier organiser, make sure both levels fit comfortably under the lowest point.
Step 4 – Map your pipe position (this matters most)
Pipe placement usually determines which organiser will work.
The three most common layouts are:
-
Pipe in the middle
Limits solid shelves but works well with expandable or segmented designs.
-
Pipe to one side
Leaves clear space for drawers or turntables.
-
Pipe running along the back
Often allows full-depth organisers at the front.
Make a quick sketch if it helps. Knowing where the pipe sits will save a lot of guesswork later.
Match your measurements to the right organiser type
When expandable shelves work best
Expandable or segmented shelves are ideal if:
- Pipes run through the middle
- Plumbing changes direction
- You need flexibility rather than fixed storage
They’re often the safest starting point for awkward layouts.
When drawers work best
Drawers are great when:
- Pipes sit at the back or side
- The cabinet is narrow
- Access is more important than maximum capacity
They make it much easier to reach items without unloading everything in front.
When turntables make sense
Turntables work well if:
- The centre floor space is clear
- You want quick, grab-and-go access
- You’re storing bottles, sprays or cleaning products
They’re simple, renter-friendly, and surprisingly effective in the right layout.
Common measuring mistakes to avoid
These are the ones that cause most returns:
- Measuring the outside of the cabinet
- Forgetting about hinges
- Ignoring the door lip at the front
- Measuring before removing existing items
- Assuming all under-sink cabinets are the same
A few extra minutes measuring properly can save hours later.
Quick checklist before you buy
Run through this before committing to anything:
- Internal width measured at narrowest point
- Usable depth confirmed
- Usable height confirmed
- Pipe position mapped
- Renter-friendly requirements checked
If you can tick all five, you’re in a good spot.
FAQs
Do I measure with everything removed?
Yes. Always measure the empty cabinet so you’re working with the true available space.
What if my cabinet isn’t square?
Measure both the front and back. Use the smaller measurement to avoid tight fits.
Can I mix different organisers under one sink?
Absolutely. Many people use shelves around pipes and drawers on one side for daily items.
Should I size up or down if I’m between sizes?
When in doubt, size down. Slightly smaller organisers are easier to position and live with.
Conclusion
Under sink storage works best when it’s planned around the space you actually have, not the space you think you have. Measuring properly helps you avoid wasted money, awkward fits and organisers that never quite work.
Once you’ve got your measurements, choosing the right solution becomes much easier.
If you’re ready to compare options, we’ve reviewed the best undersink organisers for small bathrooms and kitchens to help you decide what works best for your layout.