I co-own a small specialty coffee roastery in Asheville, NC, shipping bagged coffee and gift bundles nationwide. I was pricing shipping the same way for every order — a flat $6.99 — without actually knowing if that covered my real cost on a 5-bag bundle going cross-country versus a single bag going two states over. I suspected I was losing money on the bigger bundles but didn’t have hard numbers to check it. I use DimMath dimensional weight calculator to check the real shipping cost on each bundle size and destination zone before I set my flat rates. Now I know exactly which bundles are profitable at $6.99 and which ones need a higher flat rate or a size-based tier. It turned a guess I’d been living with for a year into an actual number I trust.