Industry standard is 18 inches. If an extra two and a half inches has been suggested by the designer? Ask him/her WHY, and if it is no reach issue for you? Have at it. You are talking about two inches................: )

I had the same dilemma. Our old kitchen was built in the 80's and we had 20" of space. I loved it because I am 5' 9". We also are installing an Ikea kitchen. The cabinets are wider than standard cabinets so with just 18" it makes it a little awkward to reach back. You also get a deeper shadow, We went with 20" again because we like the extra space and want a bright, open look. You also get to see more of the back splash which for me makes it a win/win. It might be just a few inches but I did notice a difference. It just looked more balanced and I'm a symmetry freak.

Thank you for your replies! Do you think its more contemporary/modern to go with the larger gap vs the industry standard 18"? We are really focused on having a sleek modern look to the kitchen and don't want anything looking out of place. Thank you all.

Get a real Kitchen Designer. One who understands the extreme limitations of stock cabinets like IKEA. You have a “Help Disaster” post in the making by here. Big time.

ours are 20 and it looks just fine, I think if you were in a small space where everything is at more of a premium then it becomes more important but for most kitchens it's not going to matter. There's nothing whatsoever wrong with either choice and your designer probably knows a lot more about what will look good then people who have never even seen your space

You will want to take the height of your ceiling into account. My ceiling was 8ft exactly. To have 20" of space I had to give up 40" cabinets. I went with 30" and I will use crown molding to take up the extra space since I don't want unused space overhead. Sophie was right in one respect - if you use a tall cabinet you will want the height of your regular wall cabinets to align attractively with the tall cabinet. A good designer can use filler and different sized cabinets creatively. I'm not a designer and I designed my kitchen myself with a 3-D planner. If your designer is using a 3-D program it would help if you send a link or take screenshots of your design so others can give you feedback.

Moving the upper cabinets up or down an inch or two will have little impact on the look of the kitchen. In other words, if you prefer "sleek and modern," the colors, materials and cabinets you choose will have much more effect on style than the distance between the counters and the upper cabinets.

Nothing is written in stone and anyone putting in a new kitchen should think about their particular needs. For example, a tall person might really appreciate 38 inch high counters. Someone else might be more concerned about whether their prized 20 inch coffeemaker will fit under the upper cabinets.

That said, standard counter height is 36 inches, standard distance between counters and uppers is 18 inches, and changing those dimensions requires you, or your designer, to think things through, be familiar with stock cabinet dimensions and know how far they can be adjusted.

And keep in mind that the 18-inch standard is also used by small appliance manufacturers. They design the height of things like coffee makers, etc., to fit under 18". You can go higher, but if you go lower be aware that it may affect what you can use on your counters. If you have an open island or peninsula where you do all your prep work, have the coffeemaker, etc., then it may not be an issue.

If you plan light rail, then make sure you've accounted for that as well.