Primal Play Boxer Briefs — Modal, Sizes 2T–14/16
Size guide
How to measure
Lay a pair that already fits your child flat and compare. These are garment measurements, not body measurements.
If your child is between sizes, size up.
Measurements are for boxer briefs, laid flat.
Toddler (2T-5T)
| Size | Age (guide) | 1/2 waist | 1/2 hip | Side length | 1/2 leg opening |
|---|---|---|---|---|---|
| 2T | 2 | 7.5 in (19 cm) | 9.8 in (24.8 cm) | 6.7 in (17 cm) | 4.8 in (12.3 cm) |
| 3T | 3 | 7.9 in (20 cm) | 10.2 in (26 cm) | 7.1 in (18 cm) | 5.0 in (12.8 cm) |
| 4T | 4 | 8.3 in (21 cm) | 10.9 in (27.8 cm) | 7.7 in (19.5 cm) | 5.3 in (13.55 cm) |
| 5T | 5 | 8.7 in (22 cm) | 11.7 in (29.6 cm) | 8.3 in (21 cm) | 5.6 in (14.3 cm) |
Toddler and kids sizes use different patterns. The kids block is cut slimmer through the hip and leg, and longer in the rise — so 5/6 is not simply larger than 5T in every measurement.
Kids (5/6-14/16)
| Size | Age (guide) | 1/2 waist | 1/2 hip | Side length | 1/2 leg opening |
|---|---|---|---|---|---|
| 5/6 | 5-6 | 8.9 in (22.5 cm) | 11.5 in (29.25 cm) | 8.5 in (21.5 cm) | 5.5 in (14 cm) |
| 7/8 | 7-8 | 9.7 in (24.75 cm) | 12.5 in (31.8 cm) | 9.1 in (23 cm) | 6.0 in (15.25 cm) |
| 10/12 | 10-12 | 10.8 in (27.5 cm) | 13.8 in (35 cm) | 9.8 in (25 cm) | 6.6 in (16.75 cm) |
| 14/16 | 14-16 | 12.4 in (31.5 cm) | 15.4 in (39.1 cm) | 10.6 in (27 cm) | 7.4 in (18.75 cm) |
Age is a guide only. The measurements are the authority.
Screens vary. The swatches show each color as measured on the garment.
Free shipping on US orders of $36 or more · Final sale
Buying more than one? The 3-pack is $36.
Primal Play boxer briefs are children's underwear in 90% modal, 10% spandex. The waistband is two layers of that same fabric, cut on the cross-grain, eased in, and finished at 3 cm on every size, with no separate elastic tape or strip inside it. There is no side seam and no center back seam. The seams that do exist, at the pouch sides and the crotch, are a Merrow ActiveSeam sewn at a 6 mm stitch width. A seam matters where it sits: the waistband and the hips have none underneath them. Sizes run 2T through 14/16.
Fiber: 90% modal, 10% spandex
Waistband: two layers of self-fabric, cut cross-grain, 3 cm finished height, no separate elastic tape or strip
Seams: Merrow ActiveSeam, 6 mm stitch width, at the pouch sides and the crotch; no side seam, no center back seam
Hem: 1.5 cm turnback, two-needle coverstitch
Care label: heat-seal printed inside the back, below the waistband
Labelling: one woven flag label caught in the waistband seam, wearer's left
Sizes: 2T, 3T, 4T, 5T, 5/6, 7/8, 10/12, 14/16
Most waistbands hold with a separate elastic tape or strip. This one has no separate elastic tape or strip. The band is two layers of the same 90% modal, 10% spandex as the garment, cut across the grain, eased in so it sits slightly shorter than the body it joins, and finished at 3 cm on every size from 2T to 14/16. The band is the fabric, not a component threaded through it.
Fabric & care
90% modal, 10% spandex.
Machine wash cold with like colors. Tumble dry low. Do not bleach.
The waistband
Two layers of the same soft modal as the garment, cut across the grain and eased in. There is no separate elastic tape or strip inside. The finished band is 3 cm on every size of the boxer briefs, and 2.5 cm on every size of the undies.
Sizing
Sizes run 2T through 14/16. Designed to sit flat under clothes with no bunching or riding up.
Sensory details
On the boxer briefs, a 1.5 cm turnback hem at the leg; on the undies, an 8 mm self-fabric binding, coverstitched so the edge lies flat. The waistband is two layers of self-fabric with no separate elastic tape or strip. Size and care are printed onto the inside back panel in a soft ink that will not crack or lift; the only woven label is a small flag tab on the outside seam.
The knit face is smooth and even, with no slub and no nap.
Third-party tested
Every style is tested by a CPSC-accepted laboratory for lead content, phthalates, and flammability under the Consumer Product Safety Improvement Act. We keep the test report and certificate on file.
Shipping and returns
Free shipping on US orders of $36 or more. Ships from Brentwood, Tennessee within two business days. For hygiene reasons all underwear is final sale and cannot be returned or exchanged. If your order arrives damaged or incorrect, email us within 14 days and we will make it right.
Does the waistband roll?
The band is two layers of the same soft modal as the garment, cut across the grain and eased in, so it sits flat and stays put.
Are there tags inside?
No woven tag inside. Size and care are heat-printed on the inside back panel; the only woven label is a small flag tab on the outside.
Are these seamless?
No. On the boxer briefs the leg is a turnback hem and on the undies it is an 8 mm self-fabric binding, both finished with a two-needle coverstitch, so it lies flat against skin rather than forming the ridge a standard seam creates.
How snug should they fit?
True to standard US children's sizing. Between sizes, size up.
Are these good for sensory-sensitive kids?
They are designed for kids who notice seams, tags and waistbands. We do not make medical claims.
- Two layers of self-fabric — no separate elastic tape or strip
- 3 cm finished band, every size
- No side seam, no center back seam on boxer briefs
- Care label printed, not sewn in
- 90% modal, 10% spandex
How the waistband is made
Two layers of self-fabric
The same modal as the rest of the garment, folded and cut across the grain so it keeps its shape.
No separate elastic
There is no separate elastic tape or strip inside the band.
3 cm, every size
Eased in so it sits close without pulling.