Terms of Use

Last updated October 9, 2026. By using Invitation Postage you agree to these terms.

What this site is

Invitation Postage is a free information tool. It applies published USPS rules and prices to the measurements you enter and shows the result. It is an independent site and is not affiliated with the United States Postal Service.

Estimates, not official quotes

We work hard to keep every rate and rule correct, and each one links to its USPS source. Even so, the result is an estimate. The post office decides the postage for your mail when it accepts it. Prices change, clerks apply judgment to things like rigidity, and your scale may differ from theirs.

Before you buy postage for a large batch, take one fully assembled, sealed invitation to a post office counter and have it checked.

No warranty

The site is provided as is, without warranties of any kind. To the extent the law allows, we are not liable for returned mail, postage due, wasted stamps, missed dates or any other loss that comes from relying on the site.

Acceptable use

Use the site for its purpose. Do not try to disrupt it, scrape it at a rate that harms others, or present its content as official USPS material.

Links, ads and affiliates

The site links to USPS pages and may show ads or affiliate links. We do not control those sites and are not responsible for their content. See the privacy policy for how ads and analytics use cookies.

Trademarks

USPS, Forever and other postal names are trademarks of the United States Postal Service. They are used here only to describe its services.

Changes and contact

We may update these terms; the date at the top shows the latest version. Questions go to[email protected] or the contact page. You can also read how the site gets its numbers or return to the calculator.