Recently, I was in need of a mustard yellow top to match some of my printed skirts. These days, I basically only buy plain tops from either vintage reproduction companies like Miss Candyfloss or boob-friendly brands like Urkye, BiuBiu, and Bravissimo/Pepperberry.

Urkye makes some of my all-time favorite stretchy tops in loads of colors (see here, here, and here). So naturally, I checked there first. And what do you know—they had both long- and short-sleeved tops in mustard yellow! Unfortunately, there were none of my usual size left in stock. But the tops were on sale and the perfect color, so I bought a couple in sister-sizes anyway.

With bra shopping, “sister sizing” is when you pick a bra that may be the same cup “volume” as your real size, but is off by a metric or two. It’s something you might do if the bra you want doesn’t come in your size, but is offered one cup or band off. So, for example, I frequently purchase size 30G even though my most accurate size is 28GG (UK). A lot of full-bust brands start at 30 band and stop at G-cup, so this opens me up to a lot more bra choices.

In Urkye’s case, I wear 38o/oo in their stretch items. The two tops I bought are the long-sleeved Veka and the short-sleeved Francuzka. I already own both these tops, so I know exactly how they fit. Since they’re a bit clingy, I figured sizing up in the waist or bust would be fine. And I was right!

In all these photos, I measure 37”-29”-41” and height 5’6”. Bra size is typically 28GG (UK) and I’m wearing an Ewa Michalak PL bra in size 30GG.

Here is me wearing my original short-sleeve Francuzka in 38o/oo:

You can see that it lays quite smooth over my bust, especially at the princess seams. Yet it’s not overly tight or clingy either, so there are some wrinkles where the fabric naturally bends and bunches up.

Here is me in the new Francuzka, in size 38oo/ooo (so in this case, I kept the same waist size, but went up a boob size):

Thanks to my plaid skirt, you can clearly see that it’s the same length as the 38o/oo. There is a bit of extra space around the bust, most noticeably at my armpits and just under the breasts. But across the fullest part of my bust, it doesn’t really look any looser than the o/oo. And since the fabric is a bit looser, the back actually appears slightly less bunched up.

Next up is my 3/4-sleeve Veka top in 38o/oo. This is my favorite of Urkye’s tops, and I own it in several colors:

It fits pretty much the same as the Francuzka. One thing to note is that the sleeves are a bit clingier than I prefer, leading them to bunch up at my elbows. I find myself pulling the sleeves flat throughout the day.

And here is the full-sleeved Veka in 40o/oo. So technically I went up one size in both waist and bust since, like bras, the bust size of these tops is dependent on the waist size:

One nice thing about sizing up to 40 is that the sleeves are a bit looser, so they don’t scrunch up at my elbows any more. It looks to be the same length in the torso as the 38. But it’s noticeably looser in the bust area. It still fits way better than any off-the-rack generic brand shirt, but you can see extra fabric at the armpits and underbust again. Additionally, the princess seams aren’t pulled as taught here, so you can see what looks like puckering or little wrinkles along the seam, which I think gives the appearance that my nipples are saying hello even though they’re really not.

Overall, there’s little difference in how all these sizes feel on my body and only minor differences in how they all look. So sister-sizing definitely works with these stretchy tops! I can’t speak to whether it’d be as successful in a tailored item or a dress, but I’ll definitely consider an “off size” again if my real size is unavailable and there’s a color I just can’t live without.