USPS Regional Rate Boxes vs Flat Rate: Which Saves More

Most e-commerce sellers know about USPS Flat Rate boxes — the "if it fits, it ships" pricing that ignores weight entirely. Fewer sellers know about Regional Rate boxes, and that knowledge gap costs them real money. Regional Rate uses the same concept of standardized USPS packaging with weight-independent pricing, but it factors in distance. For nearby shipments, that makes Regional Rate significantly cheaper than Flat Rate. For cross-country shipments, Flat Rate wins. Knowing when to use each option can save a mid-volume seller several hundred dollars a month.

Understanding the Two Programs

Flat Rate boxes come in four sizes: Small, Medium (top-loading and side-loading variants), and Large. You pay one fixed price regardless of weight (up to 70 pounds) and regardless of where the package is going. A Medium Flat Rate box costs the same whether it goes across town or across the country — around $14.45 at 2026 Commercial Base pricing. That simplicity is the entire appeal.

Regional Rate boxes come in two sizes: Box A and Box B. Like Flat Rate, weight doesn't matter up to 70 pounds. Unlike Flat Rate, the price changes based on the shipping zone. Regional Rate Box A costs about $8.20 for zones 1-2 (local) but climbs to roughly $15.80 for zone 8 (coast-to-coast). The boxes are free from USPS, just like Flat Rate boxes, and they're available exclusively through Commercial pricing — you can't buy Regional Rate at the retail counter.

Box A is slightly smaller than a Medium Flat Rate box, measuring 10.125 by 7.125 by 5 inches in the top-loading configuration. Box B is larger, at 12.25 by 10.5 by 5.5 inches, falling between Medium and Large Flat Rate in volume. Both sizes have side-loading variants that are flatter but wider.

Where Regional Rate Wins

Regional Rate dominates for short and medium distances. For zones 1 through 4, Regional Rate Box A is substantially cheaper than Medium Flat Rate — you'll save $4 to $6 per package. Even Box B, which is larger, saves about $2 to $5 compared to Medium Flat Rate at those same zones.

Consider a concrete example. If you're based in Chicago and most of your customers are in the Midwest and East Coast (zones 2 through 5), Regional Rate Box A at an average cost of around $9.50 beats Medium Flat Rate at $14.45 on almost every shipment. At 200 packages per month, that's roughly $1,000 in savings. Even factoring in the occasional zone 7 or 8 shipment where Flat Rate would have been cheaper, your overall spend drops meaningfully.

The crossover point — where Regional Rate and Flat Rate cost about the same — depends on the box size. For Regional Rate Box A versus Medium Flat Rate, the breakeven typically falls around zone 6. Below zone 6, Regional Rate is cheaper. Above zone 6, Flat Rate is cheaper. For Regional Rate Box B versus Large Flat Rate, the crossover is around zone 5.

Where Flat Rate Wins

Flat Rate's advantage is predictability and simplicity. If you ship nationwide and your customer base is spread fairly evenly across all zones, Flat Rate removes the guesswork. Every Medium Flat Rate box costs $14.45, period. You can bake that cost into your product pricing without worrying about zone distribution.

For sellers who ship primarily to distant zones — say a business in Maine selling to customers mostly in California and the Pacific Northwest — Flat Rate almost always wins. At zone 7 and 8, Regional Rate costs more than Flat Rate for both box sizes. In these cases, Flat Rate is effectively subsidizing long-distance shipping at the expense of local shipments.

Small Flat Rate boxes occupy their own niche. At around $8.50, they're competitive with Regional Rate Box A for zones 1-3 while being simpler. If your product fits in the smaller box, Small Flat Rate is hard to beat for simplicity unless most of your shipments go to nearby zones.

The Smart Approach: Use Both

The most cost-effective strategy isn't choosing one program over the other — it's using both and picking the cheaper option for each individual shipment. Shipping platforms like atoship show you Regional Rate and Flat Rate pricing side by side when you create a label, so you can choose the cheaper option per package.

Some sellers take this a step further by analyzing their zone distribution data. If you discover that 70 percent of your orders go to zones 1 through 4, defaulting to Regional Rate and only switching to Flat Rate for zone 6+ shipments optimizes your costs automatically. Many platforms let you set up rules that do this selection without manual intervention.

For the analytical seller, here's a rule of thumb. If your products weigh more than 5 pounds and fit in the Regional Rate box sizes, you almost certainly benefit from offering Regional Rate as your default. Heavy items in Regional Rate boxes at nearby zones represent the maximum savings compared to Flat Rate. Light items in nearby zones still save money, but the absolute dollar savings per package are smaller.

Practical Considerations

Both programs require you to use the official USPS boxes, which are free and can be ordered through usps.com. Regional Rate boxes ship to you in bundles of 10 or 25. The boxes are distinct from Flat Rate boxes — you cannot use a Regional Rate box with Flat Rate pricing or vice versa. USPS does audit this and will surcharge incorrect usage.

Regional Rate boxes have slightly more dimensional capacity than their Flat Rate equivalents at the same price tier, meaning you may fit products into a Regional Rate A box that wouldn't work in a Small Flat Rate box. If you're frequently cramming products into Small Flat Rate and wishing for a bit more room, Regional Rate Box A solves that problem while often costing less.

One limitation: Regional Rate is not available at USPS retail counters. You must create labels through a commercial shipping platform. Flat Rate, by contrast, is available everywhere — counter, online, kiosk, or platform. If you occasionally need to ship from a post office, Flat Rate is your only option from these two programs.

Using atoship for Automatic Selection

atoship's rate comparison engine automatically includes both Regional Rate and Flat Rate pricing when you enter package dimensions and destination. The cheapest option is highlighted, and you can build shipping rules that automatically select Regional Rate for nearby zones and Flat Rate for distant ones. This per-shipment optimization captures savings you'd miss if you committed to just one program.