A catalytic converter ships in a box around 24 × 12 × 10 inches at 8–25 lb depending on the vehicle. It is a normal parcel by size and weight, so price is mostly distance — but the ceramic honeycomb inside is fragile, and a used converter has value in its precious metals, so protection and often declared-value coverage matter. As with any parcel, the honest figure comes from rating your specific box on your specific lane at the speed you actually need.
The numbers here come from one live rating: 28 × 14 × 14 in at 18 lb, where UPS Ground landed at $33.29 for the Boston-to-Atlanta run below.
One query produced this whole section. On 2026-07-24 the SMKlog calculator received “Direct-fit catalytic converter for a 2012 Toyota Corolla” and a Boston, MA 02108 to Atlanta, GA 30303 route, then returned the box, weight, and rates shown here. We published its answer as-is, without weighing or measuring anything ourselves.
Direct-fit catalytic converter for a 2012 Toyota Corolla
Naming the Corolla is what earns the tight box. Converters range from compact sedan units to truck-length assemblies, and a plain “catalytic converter” would be averaged across all of them.
28 × 14 × 14 in
70 × 35 × 35 cm
Packed weight 18 lb (8 kg).
Boston, MA 02108
to Atlanta, GA 30303
Boston down to Atlanta, both ZIPs rated the moment we asked. Change the mileage and you change the quote; no packing trick moves the needle as far as the lane itself.
Here the box out-bills the metal: 28 × 14 × 14 ÷ 139 gives roughly 39.5 lb of dimensional weight, more than double the 18 lb actual, so every rate below is charged on the size figure. Losing a few inches of carton length would pull the billable weight down toward reality.
| Carrier | Service | Price | Estimated transit |
|---|---|---|---|
| UPS | Ground | $33.29 | 4-5 business days |
| FedEx | Smart Post | $43.21 | 5-6 business days |
| FedEx | Ground | $53.43 | 4-5 business days |
| UPS | Ground Saver | $53.94 | 6 business days |
Each price already contains everything you'd pay: carrier label plus SMKlog's charge, settled in full at checkout. On this particular pull, UPS Ground was lowest at $33.29. Don't bookmark the table as gospel, though. Carrier pricing is a moving target and your ZIPs aren't ours, so the only quote worth acting on is the one you run yourself today.
About 24 × 12 × 10 in once boxed. Wrap the converter so the internal honeycomb cannot rattle — pad both ends and immobilize it inside the box, since a knock can crack the ceramic substrate. For a used core with resale value, ship it trackable and consider declared-value coverage.
8–25 lb packed. Because carriers invoice on the larger of actual and dimensional weight, an over-roomy converter box quietly doubles your billable pounds. Size the carton to the part and measure it when sealed.
Distance first, then speed, then the box. Boston to Atlanta covers a lot of zone chart, and even so the same package spanned $33.29 to $53.94 across carriers and service levels on this one run. A nearby-state lane would undercut all of it; overnight air would blow past it. That variance is exactly why the calculator quotes routes, not categories.
Plan around 24 × 12 × 10 in packed. Wrap the converter so the internal honeycomb cannot rattle — pad both ends and immobilize it inside the box, since a knock can crack the ceramic substrate. For a used core with resale value, ship it trackable and consider declared-value coverage.
Typically 8–25 lb packed. The billable figure is whichever is greater: what the box weighs or its volume-based equivalent, length × width × height divided by the carrier's divisor. Check both on the finished package first, since low estimates come back as adjustment charges once the carrier scans it.
Immobilize it and pad both open ends so the ceramic honeycomb inside cannot rattle or take an impact — a hard knock cracks the substrate. A snug box with cushioning at each end is essential.
By size and weight it ships as a normal parcel, so the rate is mostly distance. Because used converters have real scrap value, ship trackable and consider declared-value coverage rather than the cheapest untracked option.
Billable weight, zone, and speed. Packed in a 24x12x10 in box at about 15 lb, a converter bills around 21 lb dimensional with UPS or FedEx — the box's bulk, not the metal, sets the floor. Distance between ZIP codes and ground versus expedited service do the rest. Put your converter's description and both ZIPs into the SMKlog calculator to see what USPS, UPS, and FedEx each want right now.
Compare USPS Ground Advantage against UPS and FedEx ground — at this size the winner flips by distance. USPS often edges out on shorter zones; UPS and FedEx tend to take over as billable weight and mileage climb. A snug box matters: trimming the 24-inch length shrinks the 21 lb dimensional figure toward the actual 15. Whatever wins, an online commercial-rate label typically costs 20-40% less than the counter price.