It will look like a kitchen prep sink. 14 x 17 is the common sink size.

Is it too late to consider a wall-mount faucet? That might allow a bigger sink. Or find an apron-front sink.

We have a custom vanity that had to become narrower, during the remodel(mistake in framing)..it's 20 inch though, not 18. The sinks(the part I can measure since they're under-mount and installed) are 11 by 17..it feels absolutely fine, but they are also bigger than whatever's suggested to you, and they're rectangles. . But we did forego the backsplash and just took our mirrors down to the very edge of the countertop, thus allowing more space for the faucets. Otherwise would be very tight and awkward. Did consider mother of pearl mosaics as the backsplash since this mosaic is so thin..but I didn't like the idea of adding another element to the bathroom..wouldn't tie in with other elements.

But I don't know your space, and maybe this mother of pearl will work our beautifully for you..or you might want to make the mirror longer so it becomes your backsplash..unless it's planned already anyway.

I would be concerned about moisture getting underneath mirror and damaging. Is this an every day bathroom? But even so, it's not like in the old days when many people washed hair, stockings in sink. IMO today's sinks are almost exclusively used for toothbrushing and hand washing, therefore size is less important for uses but more important that it's to scale with rest of bathroom.

In our case it's our master. We thought it over and consulted our builder of course..we also have a pretty good ventilation in there. But yes, of course one should consider possible scenarios.

The sink tops in all three of our bathrooms, incl our MB, are 18" deep front-to-back. They are from Sonia, and sit atop our Sonia "inspired" vanities (aka modified knockoffs).

These are not mine but pictures of customers on Amazon who bought the Nantucket 10 X 13 vanity sink.

I have the same brand but the 16 X 11 rectangle below. We are very happy with them. I worried about the 11" being way to small but it is not. I do not know your cabinet width but this sink fits an 18" depth cabinet ( there are pictures and reviews on Amazon from those with 18" depth vanities). My cabinets are 20" depth but since each of my vanity sections was smallish I wanted a little more countertop around the sink for my makeup and such.

I don't see a problem with a small sink. You only use it for brushing teeth and washing hands..

Hmm. I use my sink for washing my face after I shave (and at other times). Too small and doing that becomes difficult.

One thing that will make a difference is faucet spout placement. Too little "overhang" and using the sink is just masochistic (and messy); too much overhang and it encroaches on the usable space in the sink.

IKEA has a rectangular sink that might work if width is not also a problem -- the faucet is at one end. 13-3/8" deep.

Those sinks are too small. Good for an RV, but that's about it.

Yes, width and length matter, but don't forget depth.

The sinks in my old house and the sinks in my current house are roughly the same width and length, but the ones in the old house were plain-but-wonderfully-functional, while the shallow sinks in my new house throw water back at you if you turn on the water more than a trickle.

My overall thoughts:

- You need moderate sized sinks. Something in the range of 15x10-ish to 16x11-ish is good. Oversized serves no purpose, but tiny (i.e., those water fountains Ikea sells as sinks) would be annoying.

- Pay attention to the slope of the sink. A sink with sides that are "more straight" -- that is, more like a kitchen sink -- will be more functional than a sink with steep slopes (meaning that the sink has less capacity).

- Pay attention to how far the faucet projects over the sink. You want your water to hit the middle /the drain, and you don't want the faucet to stick out over the sink so that you have to reach around the faucet to use it.

- Don't sacrifice size for duplicate sinks.

- If you go for two sinks, don't squish them too close together.