Great advice from Sophie. Level cabinets to the high point on the floor. There are many articles and videos on the topic of scribing baseboard.

It appears OFF, is off, because the bottom shoe trim of the base is not level with the top of the base trim. One more time, please, and he may need to get creative with materials.

Or find a better installer. What is supoporting that countertop that is protruding? That looks like a mess waiting to happen?

WHY is the floor so off, and why didn't you fix that issue first? Dealing with the symptom of the problem rather than the actual problem is attempting to bury your head in the sand. And then it was compounded by putting in a badly designed cheap kitchen on top of a problem. Is this a flip?

This is not a flip or rental and this is far from a cheap kitchen. This is a 2 story upper lower duplex in a historical home. The kitchen in the lower unit is not only small but there are 3 doorways and 2 floor to ceiling windows in the kitchen. The cabinet and counter space had to be maximized and I thought we did really good with the design with what we were working with. That wall happens to be where the floor is very unlevel. I consulted with various builders and even a structural engineer and they all told me I would make the problem worse trying to level floors. Everything has been done by a professional so I would have expected they knew what they were doing. I've hounded my builder about making things level he assured me all cabinets are installed level. Countertop company also installed level. This has been a long and expensive and stressful project and I'm not looking to be beat up...just some advice.

The most important thing is that the cabinets and counter tops are level. What is going to go in that spot?

There's no room to put anything but some open shelving. I took the picture from the kitchen entry from hallway and you can see the heat vent on floor. There's really no other room there.

So there will be something there? My point being that it's not going to be as visible as it is right now. Your contractor could cheat the base a little or use a shorter base, but it's always going to look like it runs downhill a bit because it's an older house that has settled a bit. It is what it is. Or he could get a longer end panel and scribe that to the floor as mentioned previously and just finish it with just some shoe molding. I think once you get the shelving in there (and live with it it for awhile) you won't even notice it. Just for future reference though - you can add a bend to the heat run and have it exhaust through the toe kick in a cabinet.

I just remember something we did in a similar situation. Jan Moyer mentioned above that that it appears off because the shoe trim is not level with the top of the base trim. I think she's right. We used a piece of ranch casing (because it's wider but still has the curved edge) for the shoe molding and fit that to the floor. That piece will get wider as it approaches the wall but it's not as noticeable.

Old houses always are! Best of luck!

"...even a structural engineer and they all told me I would make the problem worse trying to level floors."

They were wrong. People pull brick houses across town without cracking a mortar joint and these guys can't crank a floor back to level? Nonsense.

You're getting what you've got. We're carpenters for God's sake, not magicians.

Madden above is on the money. He needs a trip to Home Depot, rescribe, and a cup of paint. Then stop staring at it. Tuck a tall woven and great looking basket under there for mail recycle,

Ps....... The REAL solution would have been a one inch trimmed "door" panel for the "skin" side, with a ripped /recessed "toe" rendering the entire thing much less awkward, the out of level floor barely noticeable, and making the cutback in counter top, unnecessary, with a bonus of more clearance in a tight spot. . And you could STILL do that. It's a tiny hunk of counter top

Stop panicking about the floor. In old houses, the floor is never level.

As long as the countertop and the cabinet is level, the bottom can be adjusted to the floor.

I have just ripped a piece of "extention molding" off the bottom of another piece of base trim to fill in the gap on the low end of the of the floor. Glue and brad the extention molding on. If its painted trim, Ill spackle the where the pieces meet and give it a light sand before paint.

I think that would work well in your situation. Sometimes you gotta get creative in old houses. They're NEVER level, plumb or square. I have the same situation in the bathroom im remodeling right now.