This KnowAnt manual is for anyone who needs to write an address on an envelope so the letter actually arrives.
Postal machines and humans read the same block of text. If the city sits above the street, or the apartment number is missing, the mail waits or bounces. How to write an envelope is layout, not style.
At KnowAnt, we treat envelope copy like any other short document: complete and unambiguous. The same habits you use in a letter apply. Write the date on the letter inside — not as a substitute for a postcode on the front.
This walkthrough covers how to write an address on an envelope to mail, including UK, Canada, apartment numbers, PO boxes, and US vs India layouts.
Table of Contents
- Where Everything Goes
- Return Address
- US vs UK vs Canada vs India
- Apartment Numbers and PO Boxes
- Common Envelope Addressing Mistakes
- Step-by-Step Checklist
- Frequently Asked Questions
- Conclusion
Where Everything Goes
On a standard letter envelope: stamp top right, recipient in the lower center with a margin, return address top left (or the back flap if that is local custom). Print in capitals if handwriting is hard to scan. Dark ink. Do not decorate the address block.
Return Address
Include a return address if you want undeliverable mail back. Use the line order your own country expects.
R. MEHTA
14 OAK LANE APT 2B
AUSTIN TX 78701
USA
For international mail, add the country on the last line of both blocks.
US vs UK vs Canada vs India
US: name; street number and name plus apartment; city, state abbreviation, ZIP. Add the country only if mailing from outside the US. Keep city, state, and ZIP on one line.
JORDAN LEE
188 PINE STREET APT 4C
BOSTON MA 02114
UK: the postcode is the sort key. Name; number and street; locality if needed; post town in capitals; postcode; country if sending from abroad. Do not invent a US-style state line.
SAMIRA KHAN
12B HIGH STREET
HEADINGTON
OXFORD
OX3 7AB
UNITED KINGDOM
Canada: close to US order, with a letter-number postal code and the province abbreviation before it. Leave the space in the code (M5H 1J8).
ALEX MARTIN
45 KING STREET WEST UNIT 1102
TORONTO ON M5H 1J8
CANADA
India: house or flat, building, street, area, city, state, six-digit PIN. Rural mail may need village, post office, and district.
ANANYA SHARMA
FLAT 3B, LAKEVIEW RESIDENCY
14 MILLERS ROAD, VASANT NAGAR
BENGALURU
KARNATAKA 560052
INDIA
Same person, four sequences: US is name / street+apt / city ST ZIP; UK is name / street / post town / postcode; Canada is name / street+unit / city PROV code; India is name / flat+building / street+area / city / state PIN.
Apartment Numbers and PO Boxes
Apartment number: put the unit on the street line when it fits (188 PINE STREET APT 4C), or on the line above the street if that country prefers it. Not on the back flap. Not “4C” with no street. “Near the temple” is not a unit.
PO box: use the box, not a street you hope a clerk will translate.
PRIYA NAIR
PO BOX 4412
CHICAGO IL 60680
Do not mix a street line and a PO Box unless that postal service says the combination is valid. One delivery point.
Common Envelope Addressing Mistakes
- No return address
- Apartment or flat omitted
- ZIP, postcode, or PIN missing or on a decorative line
- UK address with a fake “state”
- India address with only a landmark
- Recipient written top-left (that is usually the return block in US/Canada)
- Pencil, glitter, or text over the barcode area
If you typed names first, run them through KnowAnt’s grammar checker. Do not run a postal block through the paraphrasing tool — it will “naturalize” lines machines need to stay rigid.
Step-by-Step Checklist
- Confirm the country’s line order.
- Write the return address top left (or flap).
- Write the recipient lower center.
- Include unit, PO Box, or PIN/postcode.
- Add the country for international mail.
- Place the stamp. Check that nothing covers the address.
Frequently Asked Questions
How do you write an address on a letter envelope?
Return address top left, recipient lower center, stamp top right, with that country’s line order and a complete postcode or PIN.
Does the apartment number go before or after the street?
In US and Canadian mail, on the street line (APT 4C) or immediately above. In India, put the flat with the building name, then the street.
Do I need a return address?
Yes if you want the item back. Without it, undeliverable mail may be destroyed.
Conclusion
How to write an address on an envelope is a sorting instruction, not a greeting.
Match US, UK, Canada, or India line order. Put the unit or PO Box where machines expect it. Keep a return address. Put the date and the prose inside the letter. When you draft that letter, polish it on KnowAnt. Leave the postal block as plain, complete lines.