Seller Bulletin / Box Check
Box Check
Type a box’s three sides, or a mailer’s two. You get its USPS size tier, the pound where the size price drops below the weight price on USPS’s list, and that list at three zones. Most platform labels run below the list.
USPS’s list from Sun Oct 4, 2026 to Sun Jan 17, 2027. Checked Thu Nov 5, 2026.
| Parcel | Zone 1 | Zone 5 | Zone 8 |
|---|---|---|---|
| This box, by size | $7.85 | $9.04 | $10.68 |
| Under a pound, by weight | $7.33 | $8.24 | $8.95 |
| 1 lb | $8.01 size is lower | $9.29 size is lower | $11.22 size is lower |
| 2 lb | $8.39 size is lower | $10.50 size is lower | $13.42 size is lower |
| 3 lb | $9.04 size is lower | $12.12 size is lower | $16.30 size is lower |
| 5 lb | $10.35 size is lower | $14.53 size is lower | $20.24 size is lower |
| 10 lb | $12.56 size is lower | $17.81 size is lower | $26.39 size is lower |
| 15 lb | $16.28 size is lower | $22.90 size is lower | $34.66 size is lower |
| 20 lb | $17.51 size is lower | $26.68 size is lower | $42.14 size is lower |
Weights below the first row are by weight. A grey figure means the size price is the lower one at that weight. The size price stops at 20 lb.
How the rule works
USPS’s list for Ground Advantage prices a parcel two ways, by weight and by size, which USPS calls cubic. The size price comes from a tier. Multiply length, width and height in inches, each rounded down to the quarter inch, divide by 1,728, round up to the next tenth. USPS doesn’t print the next part. Tier times ten is the pound where the size price becomes the lower one. We tested all 80 cells, tiers 0.1 to 1.0 at zones 1 to 8, on the July and October lists. It holds for tiers 0.1 to 0.9; tier 1.0 takes over at 11 lb. Under a pound the weight price is always the lower one, so a small box changes nothing there.
What it can’t tell you
Your price. The dollars are USPS’s published list; most platform labels run below it on ordinary addresses, and rural ZIPs pay about list. The pound is the list’s too: on Thu Nov 5 a 12 x 9 x 6 box to an ordinary address on Etsy’s postage calculator held one price at 1 and 2 lb, well before the list’s 4 lb. Whether Etsy applies the lower price on every label, we can’t say. USPS re-measures parcels and can adjust a label, and Etsy gives 60 days to dispute.
The limits
On USPS’s rule a size price needs 20 lb or less, a cubic foot or less and a longest side of 22 in or less, and rolls and tubes don’t qualify. Etsy’s Help Center says under 20 lb and sides under 18 in.
How to check your own parcel
Price your box in Etsy’s postage calculator at two weights over a pound, say 2 lb and 3 lb. If the figure holds still, that label is priced by size. If it climbs, it’s priced by weight.
The ten size tiers on USPS’s list
USPS’s published commercial list for Ground Advantage, Sun Oct 4, 2026 to Sun Jan 17, 2027. Cubic inches are the top of each tier. Mailers stop at tier 0.5.
| Tier | Box, cubic inches up to | Mailer, length plus width | Zone 1 | Zone 5 | Zone 8 | Size takes over at |
|---|---|---|---|---|---|---|
| Tier 0.1 | 172.8 | Up to 21 in | $7.85 | $9.04 | $10.68 | 1 lb |
| Tier 0.2 | 345.6 | Over 21 to 27 in | $8.22 | $9.92 | $12.39 | 2 lb |
| Tier 0.3 | 518.4 | Over 27 to 31 in | $8.79 | $11.51 | $15.22 | 3 lb |
| Tier 0.4 | 691.2 | Over 31 to 34 in | $9.72 | $13.48 | $18.34 | 4 lb |
| Tier 0.5 | 864 | Over 34 to 36 in | $10.24 | $14.37 | $19.95 | 5 lb |
| Tier 0.6 | 1,036.8 | No mailer tier | $10.49 | $15.15 | $21.41 | 6 lb |
| Tier 0.7 | 1,209.6 | No mailer tier | $10.59 | $15.81 | $22.62 | 7 lb |
| Tier 0.8 | 1,382.4 | No mailer tier | $10.73 | $16.44 | $23.76 | 8 lb |
| Tier 0.9 | 1,555.2 | No mailer tier | $11.49 | $17.06 | $24.94 | 9 lb |
| Tier 1.0 | 1,728 | No mailer tier | $13.07 | $18.68 | $27.35 | 11 lb |
Questions sellers ask
Why can a 2 lb parcel cost the same as a 1 lb one?
The size price doesn’t move with weight. On USPS’s list to zone 5, a 9 x 6 x 2 box is $9.04 by size against $9.29 at 1 lb and $10.50 at 2 lb by weight, so size is the lower price at both. On Etsy’s postage calculator on Thu Nov 5, that box to a rural Oklahoma ZIP was $9.04 at 1, 2 and 3 lb.
Does Etsy give box pricing automatically?
Etsy’s Help Center says cubic pricing is available on qualifying labels. On Thu Nov 5, Columbus, OH to a rural Oklahoma ZIP, a 9 x 6 x 2 box was $9.04 at three weights, and a 12 x 9 x 6 box at 2 lb was $10.50, the weight price, under tier 0.4’s $13.48. Our reading: those labels took the lower of the two. That’s a few readings on one day, not a rule for every label, and Etsy says its rates are for reference only and may change.
What about boxes over a cubic foot?
No size price over a cubic foot. On USPS’s list the parcel goes by its actual weight or its dimensional weight, whichever is greater. Dimensional weight is each side rounded up to the whole inch, multiplied, divided by 139, rounded up. Enter such a box above and the result shows that weight and USPS’s list for it to zone 5, which most platform labels run below.
USPS’s published commercial list for Ground Advantage, Sun Oct 4, 2026 to Sun Jan 17, 2027, from its price files; the rounding, the mailer table and the size limits are from DMM 283. The rule of tier times ten is ours, tested on all 80 cells and re-run on every USPS filing. A reading from Etsy’s postage calculator is one parcel on one lane on one day, dated, and Etsy says its rates are for reference only and may change. The tool runs in your browser and sends nothing. Checked Thu Nov 5, 2026.
