Postal Standards
Swiss Mailbox Dimensions (in cm)
A compliant mailbox combines a letter compartment, a slot, and a delivery compartment. These minimum interior dimensions are set by Annex 1 of the Postal Ordinance and La Poste brochure 221.04.
Letter Compartment
The letter compartment holds everyday mail. The standard allows for three orientations depending on the facade: horizontal (most common), transversal, and vertical. In all cases, the slot must allow a large envelope to pass through without bending it.
Slot Dimensions
The insertion slot measures a minimum of 25 × 2.5 cm (width × height). A slot that is too small, a classic flaw in old mailboxes, forces the postman to bend the mail and is a frequent reason for non-compliance.
- — Horizontal (standard): H 10 × W 25 × D 35.5 cm
- — Transversal (narrow facade): H 10 × W 35.5 × D 25 cm
- — Vertical (reduced depth): H 35.5 × W 25 × D 10 cm (8 cm deep if combined with delivery compartment)
Delivery Compartment ("Milk Box")
The second, mandatory compartment receives small parcels, newspapers, and printed matter too bulky for the slot. A mailbox that only has a letter compartment is not compliant, regardless of its size.
- — Minimum interior height: 15 cm
- — Minimum interior width: 25 cm
- — Minimum interior depth: 35.5 cm
- — Opening (delivery flap): 15 × 25 cm (for small parcels, newspapers, printed matter)
Why These Dimensions Matter
Mail should not be bent. A slot or depth that is too small forces the postman to bend envelopes, which the standard does not allow. The 35.5 cm depth ensures an A4 envelope fits flat.
The delivery compartment avoids missed delivery notices. Without a delivery compartment, every small parcel or newspaper bundle generates a delivery notice and a trip to the post office. This is the number one reason for compliance upgrades.
Non-standard dimensions can lead to refusal of service. An undersized mailbox may be refused by La Poste. After prior notice, home delivery may be suspended (OPO art. 31 al. 2 let. c). This is why we custom-make each mailbox: we respect the Postnorm minimums while adapting the box to your facade and the number of dwellings.
Swiss Made, Compliance Guaranteed
We take measurements on site, custom-manufacture, and install. Compliance is guaranteed in writing, with a free quote within 48 hours. Helvabox offers custom mailboxes, manufactured and installed in French-speaking Switzerland. Compliance with postal standards is guaranteed. Over 20 years of experience in mailboxes.
FAQ
What are the minimum mailbox dimensions in Switzerland?
The letter compartment measures at least 10 × 25 × 35.5 cm (H × W × D) with an insertion slot of at least 25 × 2.5 cm. The delivery compartment measures at least 15 × 25 × 35.5 cm. These dimensions are in Annex 1 of the Postal Ordinance (OPO) and La Poste brochure 221.04.
Is the 35.5 cm depth really mandatory?
Yes, it is the minimum interior depth required by the standard for both the letter and delivery compartments. A shallower depth often forces the postman to bend mail, which is not permitted and can lead to refusal of delivery.
Can the slot be smaller than 25 × 2.5 cm?
No. The insertion slot must be at least 25 cm wide and 2.5 cm high to accept a large envelope (C4 format) without bending it. This is one of the dimensions most often found to be non-compliant in old mailboxes.
Can I have a mailbox larger than the standard?
Yes. The Postnorm values are minimums. A taller, wider, or deeper mailbox remains compliant as long as the slot and opening meet the minimums and both compartments are present.
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