I run a small art print shop in Eugene, OR, shipping framed and unframed prints across the US. Framed prints are the problem child of my business — the actual weight isn’t bad, but the box has to be big enough to protect the glass and frame corners, and I kept getting billed way more than I expected. I didn’t have a way to check, before I built a box, whether I was about to walk into a dimensional weight charge. I use DimMath dimensional weight calculator every time I design a new frame-size box. I enter the dimensions before I ever tape it shut, and it shows me exactly whether I’m being priced on dimensional or actual weight. That’s let me redesign my two most popular frame boxes to shave off just enough size to drop back to actual-weight pricing, which adds up fast across dozens of orders a month.