The George at Cavendish's Guide to Stamp Requirements: How Many Stamps Do You Need for Different Mail Weights?

When you send a letter from the UK, knowing how many stamps to affix isn’t just a matter of convenience—it ensures your mail reaches its destination promptly and without penalty. The George at Cavendish has put together a practical decision guide that clarifies how stamp counts vary with weight, helping curious beginners navigate the postal system with confidence.

Why Do Stamp Counts Matter?

Postage is calculated by weight and destination. If a package is underpriced, it may be returned, delayed, or incur extra fees. Conversely, overpricing ties up funds unnecessarily. Accurate stamp placement guarantees the post office can process and deliver your mail without interruption.

How Does Weight Influence Stamp Needs?

Below is a concise reference for common UK mail categories. The values reflect the standard rates for letters and postcards up to 100 grams as of the latest pricing schedule.

• Standard Letter (≤20 g) – 1 stamp (current value £0.60)
• Light Letter (21–40 g) – 2 stamps (£1.20)
• Medium Letter (41–80 g) – 3 stamps (£1.80)
• Heavy Letter (81–100 g) – 4 stamps (£2.40)
• Postcard (≤75 g) – 1 stamp (£0.60)
• Envelope with Postcard (≤80 g) – 2 stamps (£1.20)

For items exceeding 100 grams, the standard rate for parcels applies, and the calculation shifts from stamps to a single postage label that covers the total cost.

What Happens if You Undersend?

Undersending—attaching fewer stamps than required—results in a return to sender. The post office may also add a surcharge or send the item to a local branch for further postage. The sender bears the cost of re-posting, which can be inconvenient and costly, especially for international mail.

Should You Use One Heavy Stamp or Multiple Light Stamps?

There’s no legal requirement to use a single stamp per letter, provided the total value matches the rate. Some beginners prefer a single heavy stamp for simplicity, while others use multiple lighter stamps for easy tracking of payment. Either approach works, but consistency helps avoid confusion when processing.

Which Postage Options Are Best for Beginners?

For newcomers, the First Class stamp package is the most user-friendly. It includes a pre‑valued stamp for a standard letter plus a small change stamp for minor adjustments. For heavier items, the Parcel Post label is the best route—just weigh your parcel, use an online postage calculator, print the label, and attach it to the outer surface.

By following these straightforward guidelines, you can confidently determine the correct stamp quantity for any letter or postcard you send, ensuring timely delivery and avoiding unnecessary complications.