Most under-sink organizers get returned for one boring reason: they did not fit. The cabinet looked big, the organizer looked small, and then a drain pipe got in the way.
The good news is that you only need a tape measure, a pencil, and about ten minutes. This guide walks you through every measurement that matters, in the order that saves you the most trouble.
What you need
- A tape measure (inches are fine; write them down as you go)
- A flashlight or your phone light
- A pencil and the free printable checklist at the end of this post
- Everything cleared out of the cabinet
Step 1: Empty the cabinet and look before you measure
Take everything out. Cleaning sprays, sponges, that bucket from two moves ago. You cannot measure what you cannot see.
Shine a light into the back and sides. Note what you find: the drain pipe, the water supply lines, the shut-off valves, a garbage disposal, a filter system, a dishwasher hose. Anything that is not wall or floor counts as an obstacle.
Step 2: Measure the door opening, not just the cabinet
This is the step people skip. The inside of the cabinet may be wide, but everything has to pass through the door opening first.
Measure the width of the opening from one side of the frame to the other. Then measure the height of the opening from the cabinet floor to the bottom edge of the frame above it. If there is a lip or raised edge at the bottom front of the cabinet, measure from the top of that lip.
Write down the smaller of any two numbers you get. An organizer that does not pass through the door cannot be installed, however good it looks inside.
Step 3: Measure the usable width and depth inside
Now measure inside the cabinet.
- Width: side wall to side wall, at the widest and the narrowest point. Cabinet walls are not always perfectly straight.
- Depth: from the inside of the door frame to the back wall. Measure along the floor, not at the top.
Then check the floor. Many sink cabinets have a thin, removable panel or an uneven bottom, especially if there was ever a leak. Press on it. Note any dips or slopes.
Step 4: Map the pipes
The pipes decide what shape of organizer can work in your cabinet. Measure:
- How far the drain pipe sits from the left and right walls. This tells you whether a shelf can slide past it, or whether you need an organizer with a cut-out designed to go around it.
- How far the pipe comes forward from the back wall. A pipe that sticks far out leaves less usable depth than the cabinet suggests.
- How low the lowest pipe hangs. The distance from the cabinet floor to the bottom of the trap (the curved pipe) limits how tall anything can be in that area.
- Where the shut-off valves are. You need to reach them. Do not block them.
If you have a garbage disposal, measure its height from the floor and how far it extends sideways. We cover disposals and hinges in detail in our guide to the 3 things that block a pull-out organizer.
Step 5: Check the hinges and the door swing
Open the doors fully. Look for hinges that stick into the cabinet, and for any frame piece in the middle (some cabinets have a center stile between two doors). If an organizer slides out on rails, the door and its hinges must be able to clear it when it pulls out.
Measure how far into the cabinet the hinge hardware sticks out from the side wall. Write it on the checklist.
Step 6: Decide what you want to store
Measurements tell you what fits. Your stuff tells you what you need. Group it into a few piles:
- Cleaning bottles (note the tallest one)
- Sponges, cloths, and gloves
- Trash bags and a small bin
- Dish soap refills and dishwasher pods
Measure the tallest bottle. If your largest spray bottle is taller than the space under the trap, you will need to store it elsewhere, or use that area for flat items.
Step 7: Compare with the product page
When you have your numbers, put them next to the product dimensions on the page. Check these in order:
- Does it pass through the door opening?
- Does it fit within the width and depth, with a little room to spare?
- Does it clear the pipes, or does the design work around them?
- Is it low enough under the trap, if it sits under the trap?
Be careful with listings that give only one number. If a product page does not tell you the width, depth, and height clearly, ask before you buy.
Common mistakes to avoid
- Measuring only the inside. The door opening is often the smaller number.
- Ignoring the floor. A sloped or soft floor makes shelves wobble.
- Forgetting the shut-off valves. You may need to reach them in a hurry.
- Rounding up. If your cabinet is 23 3/4 inches, do not write 24. Round down.
- Measuring once. Measure twice, and write both numbers.
Quick recap
- Empty the cabinet and look at what is inside.
- Measure the door opening (width and height).
- Measure inside width and depth.
- Map the pipes, their gaps, and the height under the trap.
- Check hinges and door swing.
- Measure your tallest bottle.
- Compare your numbers with the product page.
Download the free printable Under-sink cabinet checklist (one page, direct download, no email needed) and keep it in your phone photos or on the fridge.
Ready to choose an organizer?
Once you have your numbers, you can browse options with a clear idea of what fits: see our pull-out under-sink organizer.
Measurements in this guide are general advice, not specifications for any product. Always compare with the dimensions on the product page.