LetterAgent
Mail physical letters by just asking your AI assistant.
For most letters, plain white or cream paper around standard printer weight works fine. Heavier paper feels more formal but costs more to post; lighter paper risks showing print through. Match the paper to the letter: plain for business, nicer stock for personal notes.
Paper weight is measured in grams per square metre (gsm), and in North America also in pounds (lb) for a ream of a base size, which confuses everyone. Standard office printer paper is about 75 to 90 gsm, often labelled 20 lb bond. That is the safe default for typed letters: it feeds through printers cleanly, folds well, and keeps postage at the standard letter rate. Personal stationery often runs 100 to 120 gsm, which feels thicker in the hand and takes fountain pen ink without bleeding. Above 120 gsm you are into light card, which feels impressive but can push a multi-page letter into a higher postage bracket and may jam some printers. Below 75 gsm, print starts to show through the back, which looks cheap and makes two-sided printing unreadable.
| Paper | Weight | Best for | Watch out for |
|---|---|---|---|
| Standard copy paper | 75 to 90 gsm | Business letters, everyday typing | Feels plain; fine for most uses |
| Laid or linen finish | 90 to 120 gsm | Formal letters, invitations | Textured surface can blur fine print |
| Cotton or linen content | 100 to 120 gsm | Resumes, important personal letters | Higher price; check printer compatibility |
| Lightweight airmail style | Under 75 gsm | Long letters where weight matters | Show-through; ink may bleed |
Finish matters more than most people expect. Matte, uncoated paper is the right choice for nearly every letter: it takes ink from pens and printers cleanly and is easy to read. Glossy or coated paper, the kind used for photos, smears with some pens and glares under light, so avoid it for letters. Textured finishes like laid (fine parallel lines) or linen (a woven look) add a formal feel and hide fingerprints, but very heavy texture can make small type harder to read. Colour matters too: white reads as businesslike, cream or ivory reads as personal and warm, and bright colours read as informal. For anything formal, stick to white or cream. One more detail: if you handwrite with a fountain pen, test it first. Some smooth papers feather, spreading ink along the fibres, while slightly rougher paper holds a clean line.
Printers are picky in one specific way: coated or very heavy paper can jam or smudge, especially in laser printers, where toner is fused with heat. Standard copy paper avoids all of that. Handwriting is pickier in the opposite way: very smooth paper makes ballpoint pens skip, and very thin paper lets gel ink bleed through. If you write by hand, choose paper at least 90 gsm with a light texture. LetterAgent letters are printed on standard 8.5x11 paper, single-sided, which sidesteps both problems: the weight is chosen for clean printing and reliable folding into a double-window envelope, and you never have to match paper to a printer yourself.
In a double-window envelope, the recipient's address shows through one window and the sender's through the other, and both are printed on the letter itself. Thin paper lets the body text ghost through the window area and can make the address harder for sorting machines to read cleanly. That is a real, practical reason to avoid flimsy paper for mailed letters, not just a matter of looks. The fix is simple: use paper of at least standard printer weight, keep the address block clear of body text, and print addresses in a plain, dark font. In the US, the address should sit in the lower portion of the envelope window area as the postal service expects; in Canada, Canada Post uses similar window placement rules, and a clean address block helps automated sorting in both countries.
Ready to mail it? Send your letter with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it is 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.
Need help? Ask your assistant: it can check a job's status any time. If it ever can't handle something: hello@getletteragent.com