Insulated mailers for mailbox packages
Shipping an insulated mailer as a mailbox package only works if the shipment fits within your carrier's rules. The mailer itself is light and made of bubble wrap with an aluminum layer, but the carrier decides which size and thickness is accepted as a mailbox package.
This article shows what to look for when shipping an insulated mailer and which sizes of our insulated mailers are most suitable.
Insulated mailer in the mailbox: what decides whether it fits?
With insulated mailers as mailbox packages, what counts is the dimensions of the complete shipment, not the mailer alone. You add up:
- the outer size of the mailer: 30 x 45, 35 x 35, 45 x 45 or 60 x 60 cm;
- the product that goes in, such as a small box, vial or jar;
- the cooling element or gel ice pack you add;
- the thickness the bubble wrap adds once the mailer is filled and sealed.
Compare those dimensions with the requirements your carrier sets for mailbox packages. We deliberately do not state those requirements here, because they differ per carrier and can change.
Which size insulated mailer do you choose for a small package?
Smaller sizes fit through the mailbox and save on shipping costs compared with an insulated shipping box.
| Size | Shape | Suited for |
|---|---|---|
| 30 x 45 cm | Elongated | Vials, ampoules and narrower packages |
| 35 x 35 cm | Square | Small boxes, jars and compact packages |
| 45 x 45 cm | Roomy square | Larger shipments or several items |
| 60 x 60 cm | Largest size | Large or bundled shipments |
The 35 x 35 cm mailer is compact and light, which helps with shipping costs. In practice, the larger sizes are more likely to go as a regular package. Whether a particular size still counts as a mailbox package with your carrier is something only the carrier can tell you.
How do you pack an insulated mailer for shipping?
Put the product and one or more gel ice packs in the mailer and remove the cover strip from the adhesive strip. Press the mailer firmly closed. That closes the mailer without tape. Choose a size that is just a little larger than product plus cooling element.
For the cooling element, you can look at our ice packs. Flat cooling sheets are in the ice pack sheets. How many cooling elements you need depends on the shipment and the conditions in transit. You can read a calculation method in the article Shipping ice packs: what determines the number?.
What does the mailer do and not do?
The insulated mailer insulates passively. The bubble wrap traps air and the aluminum layer reflects heat radiation, so the contents warm up more slowly. The mailer does not cool by itself and does not measure temperature. How long your product stays cold depends on the outside temperature, the amount of product, the cooling element and the transit time. We therefore cannot state a fixed duration.
If the shipment does not fit in a mailer, a box is a better choice. Look at the insulated shipping boxes or read how to choose the right box size.
Why an insulated mailer for a small package?
An insulated mailer is light and meant for small shipments, for example samples, cosmetics or a small food order. The bubble structure absorbs shocks and the adhesive strip closes the mailer without tape.
For larger shipments, choose an insulated shipping bag in your own shipping box. For longer transports, add cooling elements.
Frequently asked questions about insulated mailers and mailbox packages
Does an insulated mailer fit through the mailbox?
That depends on the size of the filled shipment and on your carrier's requirements. Smaller sizes fit through the mailbox.
Which insulated mailer should I choose for mailbox packages?
Choose the smallest size that product and cooling element fit into neatly. For many compact products that is the 35 x 35 cm mailer, for vials and ampoules the 30 x 45 cm.
Can I ship an insulated mailer without a box?
Yes, the mailer is meant for small shipments and has an adhesive strip to close it. For good temperature control, place the mailer in a sturdy insulated shipping box. For larger shipments, choose an insulated shipping bag in your own shipping box.
Shipping with an insulated mailer: order the right size
Look at the sizes in our insulated mailer collection. All insulated mailers are from our own production since 1972 and available from stock.
You will find all names in our glossary.
