Every price starts with a parcel: one order becomes one parcel, and that parcel's weight — and above 5 kg, its size — is what gets priced. This page is how the parcel is decided. Everything in it lives on Shipping → Packaging.
Your boxes
A box in TellShip is three things: its size, the weight it holds, and whether it is in use. One of your boxes is the usual box — the one orders go in when nothing says otherwise.
Every store starts with one box called Minimum parcel — 5 × 5 × 1 cm, holding 1 kg. It is deliberately tiny so it can never be the reason a price went up; an order too heavy for it moves up to a bigger box on its own.
Packing rules — you say what goes in what
A rule says "this combination ships in this box": a basket of products — picked by product, by SKU prefix, or by name prefix, each with a quantity — and the box that combination goes in. When a cart contains the basket, the rule fires; extra items in the cart don't stop it.
When two rules both match, the most specific one wins — not the one higher in the list. You never need to order your rules; you do need to make the special case more specific than the general one.
TellShip never computes how to split an order: one order is one parcel, and a rule's job is to name the box you already know it ships in.
How the box is picked, in order
- The most specific rule that matches the cart.
- No rule? Your usual box.
- Too heavy for it? The smallest of your boxes that takes the weight.
- Nothing takes it? No quote — checkout shows your other rates instead, and Test rates tells you that this is what happened.
After the box is picked, measured product sizes can shrink what is declared — never enlarge it — see Pack with dimensions.
Why the box matters — and when it doesn't
Under 5 kg the box does not change the price. Weight and destination decide, whatever you pack in — which is why Do I need to set up packaging? answers "probably not" for most stores.
Above 5 kg the box is money. A parcel can be charged on the space it takes up instead of its weight, so a box roomier than its contents raises the price — see Parcels over 5 kg.
The aim of all of it is accuracy, in both directions. A parcel declared too small undercharges shipping and you pay the difference on every order; a parcel declared too big overcharges and loses carts.
The hard limits
A parcel side must be between 1 cm and 105 cm, a parcel at most a quarter of a cubic metre, and 22 kg is the ceiling for domestic — heavier is refused rather than priced.
Watch it decide
Run any order through Test rates: the Rate factors panel shows "Packed in: …" — which box, and which rule or measurement picked it — before a customer ever sees the price. Every real quote records the same thing in Rate logs.