Is your carpenter taking in to account that the top of the rail is not where the top of the cabinet will be? He might be assuming that cabinet top will line up with the rail top, but the cabinets will be a little higher.

The Ikea instructions should be correct. We used them for our kitchen and our laundry room. We had to figure out the upper rail ourselves because we used taller cabinets and not exactly 18" difference, but the bottom rail shouldn't have too much to play with in terms of where it goes. Just make sure you find the highest spot on your floor (assuming it is not perfectly level) and measure from there.

Calculate your countertop thickness and cabinet height. Everyone uses different tops so you want to be sure your appliances fit. The legs are adjustable, but if you go too high there will be a gap above the toe kick.

The two of us just did a little test. We placed a cabinet, with legs, against the wall with a short section of the rail that we slid over the brackets on the cabinet. He adjusted the legs a touch higher to accommodate the toe kick. Also used a piece of flooring under the toe kick. From floor to bottom edge of the rail was 30.75 inches. That's nearly 1.5 inches lower than shown in the instructions. (If we followed the instructions the bottom of the toe kick would be hanging 1.5 inches above the floor.). The overall height, with the countertop we'll be getting, would be just right. So I'm just wondering what the heck is going on? *The cabinet box is 30" high. The toe kick is 4.5" wide.

Are you not supposed to measure from the finished flooring ? (at least if you have flooring below your cabinets ?)

We slid a piece of flooring under the toe kick and measured from there. New flooring is rarely, if ever, installed under the entire cabinet, just under the toe kick up to the legs. And even if we left out the depth of the new floor, the cabinets would still be too high.

This guy has a lot of good videos on youtube on how to install Ikea cabinets.

Here's a link to one. He has several videos. Hope that helps.

https://youtu.be/7NYPIOUVOKE

Re-reading your comment about your test, and the only thing I can think is that you did something wrong there. I cannot see how the bottom of your rail would be at 30.75" if the cabinet was assembled correctly and the railing is installed in the right direction.

If you look at this: https://www.northstory.ca/installing-your-ikea-sektion-kitchen/ it might help you make sure you are doing everything correctly, and help visualize it properly.

It is a little bit weird trying to get it all figured out when you are first doing Ikea, but it makes sense once you start hanging the cabinets.

I agree with Steve. The instructions if followed At 32 3/16” height leave a 5/8” gap between the bottom of cabinet and toe kick and bring the 3 centimeter quartz countertop over the 36” height. I have asked the Ikea kitchen department and they don’t really know why this is. They say that they don’t have installation expertise.

Ikea is a joke. The rail needs to be mounted at 30.75" to the bottom of rail. Unless you want some huge gaps in your toe kick. Between the rickety plastic legs and having to get your box deliveries piece meal IKEA is worth messing with anymore.

If the rail is upside down, an orientation in which it still seems to work fine btw, then the distance to the bottom is more like 30.75. If the right way up then as written in instructions 32-3/16. I figured this out the hard way (all of my upper cabinet rails are upside down!)