An undershirt development brief needs to describe the body it fits and the clothing worn over it. A chest measurement alone cannot establish whether a neckline stays hidden, an armhole moves comfortably or the hem remains inside a waistband after washing. Start with a defined wearer group, outer-shirt reference and care routine, then build the size set around those conditions.
Choose the base block before approving a size chart
Record the target body chest, waist, height and torso-length range separately from finished garment measurements. The difference between body and garment dimensions is intentional ease; the amount depends on the knit’s stretch, recovery and the desired fit. A close-fitting undershirt should not be approved simply because it can stretch over the wearer. Check whether it pulls the neckline down, presses at the armhole or creates ridges under the outer shirt.
Use the base size for initial pattern work, then test the smallest and largest sizes and any size where the grade changes. Shoulder width, chest width, armhole depth and sleeve opening must work together. Do not assume all men share a straight torso or that one chest grade accommodates every body shape.
A measurement sheet that separates the decisions
| Point of measure | Define the method | Approval evidence |
|---|---|---|
| Half chest | Flat width at a stated distance below the underarm, garment relaxed | Chest ease and recovery on the target body |
| Shoulder width | Between named shoulder-seam endpoints across the back | Seam position under the outer shirt |
| Front and back body length | Vertical drop from the named high shoulder point to each finished hem | Tucked or untucked fit after movement and washing |
| Neck width and front drop | Finished opening, not the rib attachment seam; state datum and direction | Visibility with the intended collar opening |
| Armhole depth and sleeve opening | Separate vertical depth from the curved seam or opening length | Reach, seated posture and pressure at the underarm |
| Hem width | Flat width at a defined hem location | No excessive bunching or restrictive sweep |
Add columns for every size, finished-garment tolerance, prewash measurement, washed measurement and approval status. A tolerance is the allowed manufacturing variation, not the grade increment between sizes. Keep them in different columns. The drawing must state whether a measurement includes the binding and whether the garment has been washed, relaxed and laid flat.
Specify necklines for the outer garment
A crew neck can work under a closed collar or as a deliberate visible layer. A V-neck may sit below an open shirt collar, but the result depends on the V depth and width, shirt opening and wearer. A tank removes sleeve-end lines but also removes fabric coverage at the underarm. Pick the intended use before setting dimensions. For the detailed V measurement method, use the V-neck depth specification guide.
Record the neckline material, finished band width, attachment construction and recovery requirements. If recording a stretched opening, define the load or extension procedure rather than asking an inspector to pull by feel. An opening can meet its relaxed width and still fail after repeated wear. Check the small and large sizes in addition to the base size.
Grade length independently from chest
Increasing chest size does not automatically imply the same increase in height. Decide whether the range serves one height band, offers short or tall options, or accepts a broader length compromise. Set front and back length grades deliberately. For tucked styles, wear the sample with the intended trouser rise, sit, stand and reach overhead. For untucked styles, check that the hem stays within the intended outer layer rather than hanging below it.
Measure the washed garment as well as the new sample. Fabric relaxation can alter length and width differently. Do not lengthen every pattern to compensate for one unstable fabric lot; establish fabric behavior first, then approve the finished garment.
Moisture-wicking undershirts: what changes in development
A moisture-wicking undershirt is usually made from a polyester or nylon knit, or a blend, chosen or finished to move sweat away from the skin and dry faster than plain cotton. That changes the development in three ways:
- The fabric changes the block. Synthetic jerseys often have different stretch, drape and shrinkage from cotton, so a pattern approved in cotton should be re-fitted in the new fabric rather than assumed to carry over.
- The claim needs evidence. “Moisture-wicking” is a performance claim. Decide what you mean (wicking, drying, or both) and test the finished fabric, for example with AATCC TM195, before and after the agreed washing. See what to test on wicking undershirts and what makes a fabric wick.
- Odour and finishes. If an antimicrobial finish is added, the claim needs its own evidence, and in the U.S. treated-article rules from the EPA may apply.
What an undershirt manufacturer should be able to show
- A graded measurement chart with a measuring diagram for chest, length, neck width and drop, shoulder and armhole.
- Washed versus unwashed measurements on the size set, using the agreed care procedure.
- Neckband construction and recovery method; see neckbands that stretch out.
- An opacity check under a white dress shirt in each colour; see undershirts showing through.
- Label options for a tagless back neck if required; see heat-transfer labels.
Pack quantities are a separate decision
Pack format, colour mix and order quantities do not belong in the fit specification. Keep them in the purchasing plan, and keep size ratios separate from grading: changing how many of a size you buy cannot fix a size that does not fit. The fabric weight, colour mix and pack arithmetic for wholesale orders are covered in wholesale undershirts: fabric weight and pack quantities.
Approve fit, then the production configuration
- Fit sample: approve the block, measurement definitions, neckline, armhole and length in the intended outer layers.
- Washed size set: check base and extreme sizes, revised grades and recovery using the agreed care procedure.
- Pre-production sample: confirm actual fabric, colour, seams, labels and decoration. Reopen fit approval if these materially change behavior.
- Packed sample: retain the fold, piece count, size/colour composition, barcode artwork and carton information alongside garment approval.
Branding is often minimal, so label placement, legibility and skin comfort need explicit approval. State label position from a named seam and ensure care and composition information matches the delivered product and destination requirements. Do not treat a laboratory report or certification logo as evidence without checking the product and scope it covers.
Release checklist for the buyer and QC team
Issue one version-controlled file containing the wearer brief, size chart, graded pattern reference, washed measurements, construction details, approved shade and pack breakdown. Assign neckline and armhole checks at the start of each size run, and check pack components during assembly rather than only after cartons close. Record who may approve a deviation and which changes require another sample.
For an enquiry, send this brief through the undershirt factory page or contact Knitwear Base. Ask for feasibility, sampling requirements and an itemized quotation against the specific configuration rather than assuming availability from a generic product description.
Sources and further reading
- ISO 8559-1:2017, Size designation of clothes: anthropometric definitions for body measurement
- AATCC TM195, Liquid Moisture Management Properties of Textile Fabrics
- U.S. EPA, Consumer Products Treated with Pesticides (treated articles exemption)
- AATCC TM135, Dimensional Changes of Fabrics after Home Laundering
- ISO 6330:2021, Domestic washing and drying procedures for textile testing
- ISO 5077:2007, Determination of dimensional change in washing and drying
- eCFR, 16 CFR 423.6, Care labeling of textile wearing apparel
Rules and standards are summarised from their official pages for general guidance; this is not legal advice. Check the current version and the requirements of your own market before you rely on them.
