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Dimensional weight and USPS price checker

Is your box priced by size? Its billable weight under USPS’s size rule (÷139 since July 12, 2026), and the USPS price on your ship date.Is your box priced by size?

Example box

Box14 × 12 × 12 in · 6 lb

$22.90

Published price · Ground Advantage commercial (label sites, eBay), zone 5

Billable
15 lbby size
Dim wt ÷139
15 lb2,016 cu in
Retail
$31.70Post Office counter

Priced by size: it adds $7.57 to the $15.33 real-weight price; $1.53 of that is the new ÷139 divisor.

Estimate · USPS holiday prices as of Oct 13, 2026 · label sites may charge less. See it drawn ↓

The box example · change any line

Billable 15 lb · $22.90all ↓

Use $22.90, the commercial price platform labels charge, as the label cost ineBay →Etsy →Profit →

Commercial = the price label sites like eBay, Etsy and Pirate Ship sell; the Post Office counter charges retail.

from your ZIP to the buyer’s: USPS zone chart

tubes and odd shapes are measured differently

picks the USPS price list in force

How USPS weighs this box

drawn to scale · inches and pounds

The box drawn to scale beside a one-cubic-foot cubeA box of 14 by 12 by 12 inches (2,016 cubic inches) is bigger than the dashed cube of 12 by 12 by 12 inches (1,728 cubic inches).

The dashed cube is 1 cubic foot (12 × 12 × 12 in = 1,728 cu in). This box is bigger, so USPS also weighs it by size.

USPS charges the heavier of the two: 15 lb

  • Actual weight rounded up to the pound6 lb
  • Dimensional weight (÷139) size, as pounds15 lbbillable
  • Old divisor 166 before Jul 12, 202613 lb

Priced by size. At its real weight (6 lb) this box would cost $15.33; its size adds $7.57. Under the old ÷166 rule (before Jul 12, 2026) it would bill at 13 lb: $21.37 on the same price list. The new divisor adds $1.53.

Estimate by Seller Fee Desk · USPS prices as of October 13, 2026 · not a USPS quote

Line by line

How the billable weight and the price are found
Sides, rounded up to the inchwhole inches already14 × 12 × 12 in
Volume14 × 12 × 122,016 cu in
Dimensional weight2,016 ÷ 139 = 14.50, rounded up15 lb
Actual weightrounded up to the next pound6 lb
Billable weight15 lb (dimensional weight)15 lb
Ground Advantage, commercial, zone 5Holiday prices (October 4, 2026 – January 16, 2027)$22.90
Published pricewhat USPS lists for this box$22.90

This box on every USPS service

Zone 5, under both lists USPS has published; the holiday list ends at 12 a.m. CT on January 17, 2027. On your ship date (Oct 13, 2026) the holiday list is in force. Pick a service to see it above.

Published USPS prices for this box, by service and price list
ServiceJuly listJul 12 – Oct 3Holiday listOct 4 – Jan 16
$28.95$31.70
$21.15$22.90
$35.65$39.95
$35.25$39.10
not eligiblenot eligible
not eligiblenot eligible

USPS prices and rules as of · each rule is dated in the sources ↓

Is your box priced by size? Its billable weight under USPS’s size rule (÷139 since July 12, 2026), and the USPS price on your ship date.Is your box priced by size?

How the math works

Every rule is read from the USPS Domestic Mail Manual and Notice 123 on the dates shown (checked October 13, 2026).

  1. Round each side up to the whole incha 13.2-inch side counts as 14 inches; volume = length × width × height of the rounded sidesUSPS Domestic Mail Manual 123/133/223/283 [7-12-26] · page dated July 12, 2026 · read October 13, 2026
  2. Dimensional weight, only over 1,728 cubic inches (1 cubic foot)dim weight = volume ÷ 139, rounded up to the next pound — the divisor since July 12, 2026 (it was 166)USPS Domestic Mail Manual 123/133/223/283 [7-12-26] · page dated July 12, 2026 · read October 13, 2026
  3. Parcels that aren’t rectangularGround Advantage: volume × 0.785 first, then the same test and divisor · Priority Mail: not modeled (the manual still shows 166 there)USPS Domestic Mail Manual 123/133/223/283 [7-12-26] · page dated July 12, 2026 · read October 13, 2026
  4. Billable weightthe heavier of the actual weight (rounded up to the pound) and the dim weight · under 1 lb with no dim weight: the ounce price · dim weight over 70 lb: the 70-lb price · actual over 70 lb: over the USPS limit
  5. Cubic pricing (commercial)each side rounded down to ¼ in; cubic feet = L × W × H ÷ 1,728; the smallest tier that fits, in 0.1 steps · Ground Advantage Cubic up to 1 cu ft, Priority Mail Cubic up to 0.5 cu ft · 20 lb or less, no side over 22 inUSPS Domestic Mail Manual 123/133/223/283 [7-12-26] · page dated July 12, 2026 · read October 13, 2026
  6. Surcharges addedover 2 cubic feet (3,456 cu in): +$21.00 Ground Advantage, +$35.00 Priority Mail · Ground Advantage retail, longest side over 22 to 30 in +$4.50, over 30 in +$10.00USPS Notice 123 (effective October 4, 2026) · page dated October 4, 2026 · read October 13, 2026; USPS July 2026 Price Change, Notice 123 (XLSX) · page dated July 12, 2026 · read October 13, 2026
  7. Which price listship July 12, 2026 – October 3, 2026: July 2026 prices · October 4, 2026 until 12 a.m. CT on January 17, 2027: holiday prices · later: not modeled — USPS hasn’t published those pricesUSPS July 2026 Price Change, Notice 123 (XLSX) · page dated July 12, 2026 · read October 13, 2026; USPS Notice 123 (effective October 4, 2026) · page dated October 4, 2026 · read October 13, 2026; USPS: temporary price change for the 2026 holiday season · page dated August 25, 2026 · read October 13, 2026

USPS prices as of · verified · Fee change log →

Not modeled here

Prices after the holiday list: Not modeled — No USPS price list is published for January 17, 2027 onward (as of October 13, 2026): the 8% increase and the holiday amounts both end at 12 a.m. CT on January 17, 2027 — checked October 13, 2026.

UPS and FedEx: Not modeled — their prices and dimensional-weight rules aren’t in this tool (checked October 13, 2026).

Label discounts on marketplaces and shipping apps: Not modeled — they set their own prices; the tool shows USPS’s published prices (checked October 13, 2026).

Priority Mail parcels that aren’t rectangular: Not modeled — the USPS manual (DMM 223.1.4.3) still shows the old divisor there, so the rule isn’t settled (checked October 13, 2026).

Media Mail and Priority Mail Express: Not modeled — not in this tool’s price data (checked October 13, 2026).

Other length, nonstandard and oversized charges: Not modeled — flagged as “may apply” when the box could trigger them, never priced (checked October 13, 2026).

How the numbers are checked

  1. Read on USPS’s own price lists. Every price, divisor and surcharge comes from the prices USPS publishes, with the date they were read. News and forum posts wait until USPS confirms them.
  2. Tested to the cent. Every calculator runs on one engine, and its arithmetic is covered by automated tests with worked examples — so the same sale gives the same numbers on every page.
  3. Honest about gaps. A rule that can’t be confirmed shows “Not modeled” with the reason. A rule with two fair readings shows a range, and the comparison ranks by the lower one.
  4. Dated and logged. Rates are re-checked on a schedule; every fee and price change goes into the public fee change log with its effective date.

  • Guide · Shipping

    What Shipping Really Costs Resellers: USPS, Dim Weight, Labels

    14 × 12 × 12 box: 2,016 ÷ 139 → 15 lb, $31.70

    A 1-lb USPS Ground Advantage package costs $11.70 retail or $9.29 commercial to zone 5 in holiday pricing. Dim weight at 139, cubic prices and labels.

    Updated · 5 min read

  • In-depth guide · Fees

    Seller Fees Compared: eBay, Poshmark, Mercari, Depop and More

    $50 top: Depop $47.48 down to Poshmark $40.00

    The same $50 item on eight marketplaces: what each charges its fee on, who buys the label, and why the platform that nets the most changes with price.

    Updated · 10 min read

  • In-depth guide · Pricing and profit

    How to Find Real Profit per Item: Fees, Shipping, Supplies, Miles

    $62.64 paid → $41.08 net payout → $22.71 profit

    A $50 thrift find sold on eBay, worked line by line: fees, label, item cost, sourcing tax, supplies and mileage, then margin, ROI and markup.

    Updated · 10 min read

Gear for this job

Shipping4 itemsmakers’ pages read

As an Amazon Associate, Seller Fee Desk earns from qualifying purchases. Amazon links are marked “(paid link)”; prices aren’t shown here.

How gear is chosenAll 10 shipping items

Sources

  1. USPS Domestic Mail Manual 123/133/223/283 [7-12-26] (page dated July 12, 2026)USPS · read
  2. USPS July 2026 Price Change, Notice 123 (XLSX) (page dated July 12, 2026)USPS · read
  3. USPS Notice 123 (effective October 4, 2026) (page dated October 4, 2026)USPS · read
  4. USPS Postal Explorer: Price change (page dated October 4, 2026)USPS · read
  5. USPS: time-limited 8% price change (page dated March 25, 2026)USPS · read
  6. USPS: temporary price change for the 2026 holiday season (page dated August 25, 2026)USPS · read