How to Read a Technical Specification (Tech Pack)
A technical specification—often called a tech pack—is the blueprint for your product. It tells a manufacturer exactly what to make, how to make it, and what standards to meet. Learning to read one correctly saves time, reduces errors, and ensures your product matches your vision.
1. Understand the Header Information
Every tech pack starts with a header. This section includes the product name, style number, season, and date. It may also list the designer, brand, and target market. Always check that the header matches your purchase order or design brief. A mismatch here can cause confusion later.
2. Review the Bill of Materials (BOM)
The BOM lists every component in the product: fabrics, trims, threads, zippers, buttons, labels, and packaging. Each item should have a supplier code, color reference, and quantity per unit. Look for notes on alternative materials or approved substitutes. If a material is listed as “TBD” (to be determined), flag it before production begins.
3. Examine the Technical Drawings
Flat sketches show the product from front, back, and side views. They include construction details like seam types, stitch counts, and pocket placements. Callouts (arrows or circles) point to specific features. Compare these drawings to your original design to ensure proportions and details are correct.
4. Check the Measurement Spec Sheet
This is a table of critical measurements for each size. It includes body length, chest width, sleeve length, waist, and more. Each measurement has a tolerance (e.g., ± 0.5 cm). Pay attention to “point of measure” diagrams—they show exactly where to measure. If a measurement falls outside tolerance, the garment may not fit properly.
5. Read the Construction Notes
These notes describe how the product is assembled. They cover stitch types, seam finishes, hem styles, and reinforcement areas. Look for instructions on topstitching, bar tacks, or specific thread tensions. If you see a note like “match stripe at side seam,” it means the fabric pattern must align—a detail that affects fabric yield and cost.
6. Understand the Grading Rules
Grading shows how measurements change between sizes. For example, a shirt might increase 1 cm in chest per size. The grading rule is usually listed as a table or formula. If you plan to offer extended sizes, confirm the grading is consistent and proportional.
7. Review Labeling and Packaging Instructions
This section specifies care labels, content labels, brand tags, and hang tags. It also includes packaging details like polybag type, barcode placement, and carton quantities. Errors here can lead to returns or fines, so verify every label matches your brand guidelines.
8. Look for Quality and Testing Requirements
Many tech packs include a section on testing standards. This may cover colorfastness, shrinkage, seam strength, or flammability. The manufacturer will use these to validate the product before shipment. If no testing is listed, ask your supplier what standards they follow by default.
9. Check the Revision History
A tech pack is a living document. The revision history shows changes made over time—date, description, and who approved them. Always work from the latest revision. Using an old version can result in incorrect production.
10. Common Mistakes to Avoid
- Skipping the BOM: Missing a trim or using the wrong thread can delay production.
- Ignoring tolerances: A 0.5 cm difference might not matter for a tote bag, but it can ruin a fitted jacket.
- Assuming the manufacturer knows: If a detail isn’t written down, it won’t be made. Be explicit.
- Not confirming the point of measure: Different factories measure differently. Use diagrams to avoid confusion.
Frequently Asked Questions
Do I need a tech pack for every product?
Yes, even simple products benefit from a tech pack. It prevents misunderstandings and provides a legal record of your specifications.
How detailed should my tech pack be?
As detailed as possible. Include every material, measurement, and construction note. The more information you provide, the fewer questions and errors you’ll have.
Can I use a template?
Templates are a good starting point, but customize them for your product. Generic templates may miss industry-specific details.
Who should review the tech pack before sending to a factory?
Your design team, product developer, and quality assurance team should all review it. A second set of eyes catches mistakes.
Reading a tech pack is a skill that improves with practice. Start with these basics, and you’ll communicate your product requirements clearly and confidently.