Shipping Profit Calculator

“Free” shipping just moves the cost into your item price. What matters is the total: item price + shipping charged − fees − label − packaging. Marketplaces charge their percentage fee on shipping too, so a $10 shipping charge does not net you $10. Use this calculator to find your break-even charge, then decide whether to bake it into the price or charge it separately.

Carriers bill by whichever is greater: the package's actual weight or its dimensional weight — the volume of the box divided by a “DIM divisor.” UPS daily rates and FedEx use a divisor of 139 cubic inches per pound; UPS retail (counter) rates use 166. USPS uses 139 but only applies dimensional weight to packages larger than one cubic foot (1728 cubic inches). A big, light box can cost far more than its scale weight suggests.

Yes — effective July 12, 2026, USPS changed its dimensional-weight divisor from 166 to 139 and now rounds each box dimension up to the next whole inch (Domestic Mail Manual, revision 7-12-26). That makes large, light USPS packages more expensive than before, and it means most older calculators using ÷166 now overestimate what you can fit per pound. This calculator uses the current ÷139 rule.

Use the smallest box that safely fits the item — an inch off each dimension compounds. For example, going from a 14×14×14 box to a 12×12×12 box cuts cubic volume by about 37%, which can drop billable weight by several pounds. Poly mailers avoid most DIM issues for soft goods.

If you value your time at $0, every sale looks profitable. Enter an hourly rate — even a modest one — and the calculator converts your packing time into a per-order cost. It's the honest way to compare a $6 profit that takes 5 minutes with an $8 profit that takes 40.

Yes. Marketplace labels (eBay, Etsy) and shipping platforms give most sellers commercial rates well below retail counter prices. If you buy labels at the post office counter, you are almost certainly overpaying.