I just spent ages trying to work this out, so here’s a quick post to remind myself should it ever come up again:

• The current value of a Forever stamp is 49 cents at time of writing (check current value with this search
• The USPS have an online calculator to work out postage values located here
  • To send a post card (with a value of $0) it costs $1.20 per card, or 3x Forever stamps
  • To send a rectangular letter (i.e. birthday card) weighing 1oz or less (with a value of $0) it costs $1.20 per letter, or 3x Forever stamps

You can legally use multiple Forever stamps on a single item of post to ensure that the postage cost is covered.

Michael Heap

Michael is a polyglot software engineer, committed to reducing complexity in systems and making them more predictable. Working with a variety of languages and tools, he shares his technical expertise to audiences all around the world at user groups and conferences. You can follow @mheap on Twitter