PostageCalculator.ca
Canada Post letter postage, explained simply. Rates effective January 13, 2025.

How many stamps do I need?

For a normal letter within Canada: one Permanent™ stamp. The general rule is simpler than people expect — stamps are just money. Add up any stamps you like until the total covers the postage. This page works out the cheapest combination from the stamps you actually have.

Step 1 — find your postage

Size limits — standard: max 245 × 156 × 5 mm and 50 g · oversize: max 380 × 270 × 20 mm and 500 g · minimum 140 × 90 mm. Bigger or heavier than the oversize maximum is a parcel, not a letter.

Step 2 — build the combination with the least overpay

Enter how many of each stamp you have in the drawer. The finder minimizes overpay first, then the number of stamps — that is all "cheapest" means here: the lowest total stamp value that covers the postage. This is the practical way to use up old low-value stamps — Canada Post sells 1¢–10¢ denominations precisely for topping up.

Common combinations

You're mailingPostageEasy combinations
Letter in Canada, ≤ 30 g$1.241 × Permanent™
Letter in Canada, 30–50 g$1.75Permanent™ + 50¢ + 1¢ · or the $1.75 stamp
Letter to the USA, ≤ 30 g$1.75USA stamp · or Permanent™ + 51¢ in small stamps
Letter to the USA, 30–50 g$2.61$2.61 oversize stamp · or 2 × Permanent™ + 10¢ + 3¢
International letter, ≤ 30 g$3.65International stamp · or 3 × Permanent™ (overpays 7¢)
Oversize in Canada, ≤ 100 g$2.61$2.61 stamp · or 2 × Permanent™ + 10¢ + 3¢
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Using old stamps

I found stamps marked 85¢, 99¢, $1.07 — are they garbage?Not at all. Denominated stamps are worth exactly what's printed on them, forever. A 99¢ stamp plus a 25¢ stamp mails a standard letter today. Collectors aside, face value is their floor.

What about really old stamps — 1960s, 1970s?Unused Canadian stamps from the modern era remain valid for postage at face value. Tiny denominations (1¢–8¢) are perfect top-ups. (Genuinely old mint stamps can occasionally be worth more to collectors than face — if you have full sheets or blocks, it's worth a glance at collector prices before spending them.)

Can I use a USA or international stamp on a letter within Canada?Yes. The names describe their original purpose, not a restriction. Their dollar value counts anywhere.

What happens if I underpay by a few cents?Best case, the letter arrives postage-due; worst case, it's returned to you. Not worth saving 10¢ — always round up.

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