LetterAgent
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Standard lettermail is a regular rectangular envelope, light and flat enough to run through sorting machines at the base rate. Anything that jams or fools the machines: square envelopes, rigid or lumpy contents, odd sizes: falls into nonstandard or oversize and costs more. The shape of the envelope decides the price band as much as the weight does.
| Band | What qualifies | Common trap |
|---|---|---|
| Standard | Rectangular envelope, flat, flexible, address parallel to the long edge | Forgetting that weight has its own tiers inside this band |
| Nonstandard | Square envelopes, rigid contents, lumpy or uneven thickness, odd proportions | A square greeting card that looks like it should cost the same |
| Oversize | Larger envelopes and flats that exceed standard dimensions | Mailing a document flat in a big envelope instead of folding it |
Sorting machines are built for rectangles: they read the address, spray a barcode, and fling the envelope into the right bin at speed. A square envelope tumbles unpredictably through that machinery, so it gets kicked out for manual handling, and manual handling costs more. The US has the same concept under a different name (the nonmachinable surcharge), and square envelopes trigger it there too. If you love the look of a square card, budget for the surcharge or accept that it may travel slower.
Anything that stops the envelope from flexing: keys, coins, pens, USB sticks, thick stacks of photos. These don't just cost more, they can jam the machines and damage other people's mail, which is why the surcharge exists. The practical fix is a padded mailer or a small box, which is priced as a parcel anyway. Don't try to sneak a rigid object through as a standard letter: at best you pay the surcharge at the counter, at worst the envelope tears open in the machinery.
More than you'd think. Machines expect the address block parallel to the long edge of the envelope, roughly centered, with a clear zone around it. Addresses written vertically, crammed into a corner, or printed over a busy background pattern force manual handling. Dark ink on a plain light envelope, address parallel to the long edge, stamp in the top right: that's the layout every sorting machine on earth is happiest with.
Shape decides the band, but weight decides the step inside it: standard lettermail has its own weight tiers, so a ten-page letter can cost more than a two-page one even in the same rectangular envelope. A kitchen scale settles it in seconds. When in doubt, take it to the counter: underpaying means the letter comes back to you or arrives postage-due.
Ready to mail it? Send your letter with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it's printed and mailed.
LetterAgent is a working name. Prices include print, postage, and our service fee. US prices in USD, Canadian prices in CAD (Canadian prices exclude applicable sales tax, added at checkout). Currently in private testing.
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