Why Leggings Gap at the Back: Every Size Chart Assumes a 9- to 11-Inch Hip Drop

Pull a tape around your waist, then around your hips, and subtract. If the answer lands outside 9 to 11 inches, the gap at your lower back is not a defect in the leggings. It is arithmetic.

Every size chart on this page was read straight from the brand's own sizing page on Sept. 17, 2026, converted to a single midpoint per size, and lined up. Nothing here is a review. It is subtraction.

What is the waist-to-hip drop, and why does it decide the gap?

A legging chart gives you two numbers per size: a waist and a hip. Pick a size and you are agreeing to both. The difference between them — hip minus waist — is the shape the pattern was cut for.

Say a chart's M is a 29" waist and a 39" hip. That is a 10-inch drop. If your hips are 39" but your waist is 26", your drop is 13. The M will sit correctly over your hips and carry three spare inches of fabric circumference at the top. Stretch fabric hides some of it. The rest shows up as a pocket of air at the small of your back, usually right after you sit down.

The reverse case is quieter but more uncomfortable. A 6-inch drop in an M means the hip is fine and the waistband is two inches too small, so the band rolls down over the course of a walk. Neither problem is a sizing mistake. Both are a mismatch between your drop and the chart's.

What drop do the big charts actually assume?

Here is every size on five women's charts, with the drop calculated. Where a brand publishes a range, the midpoint is used; where it publishes one number, that number is used as is.

Source: CRZ Yoga size guide, women's bottoms; Girlfriend Collective sizing; POPFLEX size guide table; Baleaf 27" Thermal Fleece High-Waist Yoga Leggings product page; Bubblelime BWWB009 product page. All checked Sept. 17, 2026. Girlfriend's 5XL and 6XL also sit at 11.0" and are left off for width.

Which brand holds its drop steady, and which one moves?

CRZ Yoga is the flattest of the five. From XXS to XL its drop wanders by two tenths of an inch: 10.5, 10.6, 10.4, 10.5, 10.5, 10.5. Whatever letter you land on, the same body shape is being assumed, which is part of why its letters track so predictably against other brands — something covered in the CRZ Yoga brand notes.

Girlfriend Collective goes the other way on purpose. Its drop is 10.0" at XXS and XS, 10.5" at S, then 11.0" for every size from M through 6XL. The chart is telling you that above a 28" waist it expects proportionally more hip, and nine consecutive sizes are cut to the same fuller shape. In a straight comparison at XL the two charts do not overlap at all.

PopFlex moves the most, and not in one direction. Its drop starts at 10.0" through S, narrows to 9.5" at M, bottoms out at 9.0" for L and XL, then springs back to 10.0" for the entire 1X–3X run. In practice that means the L and XL are the two straightest-cut sizes on any chart here.

Baleaf sits between them, tightening from 10.0" at S and M to 9.5" at L and XL before widening again. Worth remembering that Baleaf does not publish one house chart at all — each product carries its own, which is why the Baleaf measurements have to be read per style.

Does the same brand keep one drop across its own styles?

Not necessarily. Bubblelime publishes a chart per product rather than one for the store, and the three pulled today do not agree with each other.

Source: BWWB009, BWWB008 and BWWB068 product pages, checked Sept. 17, 2026. BWWB068 also prints a thigh row: 9" at XS rising half an inch per size to 11.5" at XXL.

Two things fall out of that table. The drop is rock steady inside each style, so a brand can be perfectly consistent and still cut three different shapes. And BWWB008 runs a full two inches wider per letter than BWWB009 — its XS waist, 25", is BWWB009's S. Quoting "the Bubblelime chart" without naming the style is meaningless, which is the same trap that makes cross-brand letters unreliable in the five-brand label comparison.

Where do the charts leave a hole you can fall into?

PopFlex's XL hip band ends at 47" and its 1X hip band begins at 48". A 47.5" hip has no size. The waist columns run continuously — XL ends at 38", 1X starts at 38" — so the hole exists only on the measurement that matters most for leggings.

Baleaf leaves a narrower one in the same place: the L hip band tops out at 42" and XL starts at 42.5". CRZ leaves no hole because it publishes single points instead of bands, but single points create the opposite problem — a 36" hip sits between the S (37") and XS (35") with nothing to tell you which way to go. The between-two-sizes rule is built for exactly that.

How do you measure your own drop in two minutes?

Stand up straight, no shoes, wearing something thin. Run a cloth tape around the narrowest part of your torso, between the bottom rib and the top of the hip bone, level all the way round and snug without compressing. Write it down. Then put your feet together and take the tape around the fullest part of your seat, usually 7 to 9 inches below the waist line. Write that down too, and subtract.

Take both numbers twice. A tape that rides half an inch high at the back will read one to two inches small, which is enough to move you a whole size. The longer version of the method, with the two spots brands actually mean, is in how to measure for leggings.

What if your drop is bigger than 11 inches?

Size to the hip number, every time. Hip fabric has nowhere to go; waistband fabric does. Then look for three things on the listing before you buy: a waistband at least 4 inches deep, a drawcord, and any mention of a contoured or V-shaped back rise. A 4-inch band spreads two spare inches of circumference over a wide surface, so it reads as a soft ripple rather than a fold.

Compression helps here and so does fabric. Anything above roughly 20% spandex pulls a surplus waistband closer to flat; a cotton-feel blend at 13% does not. That difference is measurable and is laid out in the fabric and size chart notes. A pair you have to return costs more than the extra minute of reading, especially on sale stock — sister site Activewear Deals keeps a running list of which stores treat discounted leggings as final sale.

And if your drop is under 9 inches?

Size to the waist. On a straighter frame the hip measurement is rarely the binding one, because stretch panels cover a couple of spare inches through the seat without sagging, while a tight band digs in from the first minute. PopFlex's L and XL, at a 9.0" drop, are the closest thing to a straight cut in this group; Bubblelime's BWWB068 at 9.5" flat is next.

One caution. Sizing down to fix a loose waistband also shortens the rise, which pulls the crotch seam up and can shorten the effective inseam by a quarter inch or so. If you are already at the edge of a length, check the inseam by height table before dropping a size, and read the PopFlex and Baleaf comparison if you are choosing between a height-based chart and an inches-based one.

What should you do before checking out?

1. Measure waist and hip twice; subtract.
2. Find your drop in the table above. Inside 9–11 inches, pick a size normally.
3. Outside it, size to the hip if your drop is larger and to the waist if it is smaller.
4. Open the chart on the actual product page, not the store's general one — Bubblelime and Baleaf both publish per style.
5. Check the return window before you order two sizes.

More of these are collected in Fit Notes, and the full measured tables by brand live in Size Charts.