How to Measure Yourself for TomboyX Bras and Underwear Sizing
By tomboyx | Premium Underwear for All Day Comfort. Fit for You. | Published: 2026-10-13
Category: How-to Guides
Learn how to measure your chest and hips at home so you can order TomboyX bras and underwear with confidence, plus how to use fit notes when your numbers fall between sizes.
Quick answer
Measure your ribcage and your full chest for bras, and your waist and hip for underwear, using a soft tape held level and snug but not tight. Write both numbers down before you open any size chart, then read the fit notes on the product page, since compression styles like the Compression Plus Adjustable run firmer than a standard bra.
Take two chest measurements, not one
Most sizing mistakes start with a single chest number. Bras and compression tops sit differently depending on your ribcage, so measure both. First, wrap the tape around your ribcage directly under your bust, keeping it parallel to the floor and exhaling normally. Second, measure around the fullest part of your chest, usually across the nipple line, with the tape loose enough to slide one finger underneath.
For underwear, the two numbers that matter are your natural waist, the narrowest point above your belly button, and your hip, the fullest point around your seat. Keep the tape level at the back. If you are measuring alone, do it in front of a mirror so you can catch a tape that has ridden up.
Decide where you want compression to sit
Fit is not only about circumference. A high-waist tucking style and a compression top both rely on where the garment anchors on your body, so note whether you prefer hold across the ribcage, the waist, or the hip. That preference tells you which measurement to prioritize when two sizes both look plausible on paper.
If you want a smoother silhouette under clothing, a firmer anchor point matters more than a tighter overall fit. If you want everyday comfort, prioritize the measurement closest to the edge of the size range so the fabric has room to move with you.
Read the fit note before the size chart
Product pages carry fit notes that a generic chart cannot. The Compression Plus Adjustable, for example, is described as delivering about 20% more compression than the bestselling Compression Top, which means your usual size may feel noticeably firmer. Adjustable shoulder straps also let you tune the hold after it arrives, so the strap setting is part of your fit, not just the size label.
For lower-body styles, the Tucking Boy Shorts use a high waist and a cheeky cut, so the waist measurement often predicts comfort better than the hip measurement alone. When a size chart and a fit note disagree, trust the fit note for that specific style.
Re-measure when your body or your laundry changes
Measurements shift with weight changes, hormone cycles, and training load, so re-check every few months rather than once. Fabric also relaxes over time: a bra that fit snugly on day one may feel looser after repeated washing, especially if it is dried on high heat.
Wash and dry according to the care instructions on the garment, and re-measure before you reorder. If you are between sizes and the style has no adjustable element, size up for daily wear and reserve the firmer size for short-duration wear.
Your measuring sequence, step by step
- Gather a soft tape and a mirror: Use a flexible fabric tape, not a metal tape measure, and stand in front of a mirror so you can see whether the tape stays level all the way around. Checkpoint: if you only have a rigid tape, use a piece of string and measure it against a ruler afterward.
- Measure your ribcage under the bust: Exhale normally, keep the tape parallel to the floor, and record the number to the nearest half inch. Common mistake: pulling the tape tight enough to compress your ribs, which makes the band size read too small.
- Measure your full chest: Wrap the tape around the fullest part of your chest, keeping it level at the back and loose enough to slide one finger under. Checkpoint: the tape should touch your skin without pressing into it.
- Measure your waist and hip for underwear: Find your natural waist above the belly button, then the fullest point of your hip, and write both numbers down. Common mistake: measuring over thick clothing or a waistband, which adds inches you do not have.
- Compare both numbers to the size chart: If your chest and ribcage point to different sizes, choose the size that matches your ribcage for bras and compression tops, and your waist for high-waist styles. Checkpoint: note whether the style has adjustable straps or stretch, since that changes how forgiving the fit is.
- Order one size, then verify on arrival: Try the garment on over clean skin, move your arms and sit down, and check for digging, riding up, or gaping before removing tags. Next step: if the band rides up but the cup area fits, adjust straps or exchange rather than layering a second size.
Product facts that affect your size choice
- Compression Plus Adjustable: Strong compression with adjustable shoulder straps that let you customize your comfort level, prevent armpit chafe, and dial in your ideal amount of lift and hold; expect about 20% more compression than the bestselling Compression Top. If you normally wear the standard Compression Top, your usual size will feel firmer here, so use the straps to fine-tune hold rather than sizing down.
- Tucking Boy Shorts - X=: Designed with a high waist and a cheeky fit, using double-layered interlock polyester with 1-way stretch for snug, secure compression while retaining breathability and moisture wicking. The high waist means your natural waist measurement predicts comfort, and the 1-way stretch gives firm hold in one direction without squeezing everywhere.
