Best size chart builder for teachers

The size chart space is dominated by generic ecommerce tools (Printful, Shopify's built-in charts, Etsy templates) that weren't designed with educators in mind—they assume you're selling globally standardized products, not kids' hoodie fundraisers or class reunion tees. Roughly 15-25 dedicated size chart makers exist, but almost none are education-focused; teachers end up patching together solutions from multiple platforms or abandoning the effort entirely. The real gap is specificity: teachers need charts for youth XS-XXL, they need to add school/grade context, they need something dead simple with zero design overhead, and they need it to integrate directly with print-on-demand vendors they already use. Most existing tools are either too technical (aimed at fashion brands) or too generic (all industries lumped together). A vibecoder building here should focus on a guided, template-first approach where a teacher selects their product type (youth apparel, adult apparel, etc.), inputs their specific sizes once, and gets a professional chart they can drop into Printful, CustomInk, or their Shopify store in under 5 minutes. The secondary insight: bundle this with a simple order-management dashboard so teachers can track who ordered what size—that's where real stickiness happens.