USPS length + girth: which size tier is your box in?

Enter the three outside dimensions. You get the sum USPS actually uses, the tier it falls into, and how many inches you are from the next threshold.

Length (in)

Width (in)

Height (in)

121.0 inches · L + 2W + 2H

108–130 band

9.0 inches from the 130-inch limit

Dimensions must be outside measurements, rounded up to the next whole inch the way USPS measures. Length is the longest side, not the side labelled "length" on the carton.

The four bands

L + 2W + 2H	What it means	Source
under 84 in	No size-based surcharge. Billed on actual weight unless the box exceeds 1 ft³.	DMM 253
84 – 108 in	Balloon pricing if the parcel weighs under 20 lb — it bills as 20 lb.	DMM 253.1.4
108 – 130 in	Oversize rate applies on the services that have one. Not all do.	DMM 253 / 601
over 130 in	Not mailable. Also triggered over 70 lb.	DMM 601.1.2

Over 130 inches, the parcel does not ship. If USPS finds it in the network, the mailer is assessed an overweight/oversize fee of $200 — raised from $100 on July 12, 2026 — and the parcel is held until it's paid. This is not a rate increase; it's a fee on a package that was never mailable.

DMM 601.1.2.3 as revised by Postal Bulletin 22702, effective 7/12/2026.

Three things that surprise people

1. Girth is not the distance around the box in one direction

Girth is measured around the thickest part, perpendicular to the length — that's 2 × (W + H), not W + H. Writing it as L + W + H understates the number by the width plus the height, and that's usually enough to move a box into a different band.

2. "Length" is the longest side, not the one printed on the box

USPS measures length as the longest dimension of the parcel, whichever flap it's on. If your carton says 30 × 20 × 14 but you measure 31 after packing, the length is 31 and the whole calculation shifts.

3. The 84–108 band costs money even when nothing is "oversized"

A 9 lb parcel in that band bills as 20 lb. Nothing on the label says "surcharge" — the weight just comes out wrong compared to what you put on the scale. This is the most common source of "why is this one $30 more than the last one".

Checking a box takes ten seconds. Checking ninety days of shipments doesn't.

If you ship more than a handful of parcels a week, the question isn't whether one box is over a threshold — it's how many of your last few thousand already are, and which fix removes the most of them.

That's what the audit does: send a 90-day export from your label platform, get back a line-by-line list.

See what the audit includes →

$49, 48-hour turnaround, refunded if it doesn't identify a package you should change.