---
title: "What is dimensional mail?"
description: "Dimensional mail is any piece with physical bulk: a box, tube, or lumpy envelope. The postal service prices it as a parcel, not a letter."
canonical: https://trysincerely.com/glossary/dimensional-mail
last_updated: 2026-09-18
---
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# What is dimensional mail?

> Dimensional mail is any piece with physical bulk: a box, tube, or lumpy envelope. The postal service prices it as a parcel, not a letter.

Source: https://trysincerely.com/glossary/dimensional-mail

Dimensional mail is any mail piece with physical bulk: a box, a tube, or an envelope with something lumpy inside. The name comes from postal pricing, where a piece that is not flat ships as a parcel instead of a letter. In B2B it usually means a gift or object sent to open a door at a high-value account.

## Why it matters

Bulk gets opened. A box on a desk does not look like marketing, so it survives the gatekeeper and the recycling bin in a way a [self-mailer](https://trysincerely.com/glossary/self-mailer) or postcard cannot. That is the whole trade: you pay parcel postage plus the cost of the object, usually tens of dollars per piece all-in, to make one recipient stop and look.

The economics only work at the top of the pyramid. Dimensional mail fits a ten-account executive play inside an [ABM](https://trysincerely.com/glossary/abm) program, not a thousand-piece prospecting run. At scale, the same budget mails far more letters and postcards, and [flat formats](https://trysincerely.com/formats) are easier to test, measure, and repeat.

It also carries operational drag. Someone has to source the object, kit it, and ship it, which is why gifting platforms like Sendoso and Postal exist. Sincerely's [46-item catalog](https://trysincerely.com/gifts) covers curated physical gifts in the United States and Canada, but it does not offer arbitrary dimensional-mail kitting or warehousing. If custom boxes are your play, a gifting platform is the better tool, and our [gifting platform comparison](https://trysincerely.com/vs-gifting-platforms) covers when each makes sense.

## Example

You target 15 accounts stuck in late-stage deals. Each economic buyer gets a book relevant to their initiative with a handwritten-style note. Call it $45 per piece shipped to make the arithmetic concrete; your real number depends on the object and the carrier. Total spend is under $700, and one revived deal pays for the program many times over.

Dimensional mail is attention bought by the cubic inch: expensive per piece, so save it for the accounts that justify it.

## Related questions

- [What is tactile marketing?](https://trysincerely.com/glossary/tactile-marketing): Tactile marketing is physical marketing: direct mail, dimensional mail, branded gifts, and other delivered objects.
- [What is variable data printing?](https://trysincerely.com/glossary/variable-data-printing): Variable data printing changes text, images, and offers for each piece without stopping the press. How it works for account-based mail.
- [How to send gifts to prospects without making it awkward](https://trysincerely.com/guides/how-to-send-gifts-to-prospects): A prospect gift can add weight to a real business reason, but it should never make a meeting feel owed.

---

Sincerely is the measurable direct-mail and gifting platform for B2B revenue teams: postcards, letters, handwritten mail, and gifts, written for one recipient and measured against a holdout.

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