USPS prices the United Kingdom of Great Britain and Northern Ireland on Price Group 20 for its weight-based Priority Mail International, Priority Mail Express International and First-Class Package International Service, and on the cheaper Price Group 5 for their flat-rate boxes and envelopes. At the weights people actually ship — 1, 5, 10 and 20 lb — that comes to $69.70 to $177.50 for Priority Mail International, $93.15 to $197.25 for Priority Mail Express International, and $23.05 to $64.25 for First-Class Package International Service under its 4 lb ceiling. Every figure below is copied from USPS Notice 123, effective July 12, 2026, read on 2026-08-30.
The UK prices worse by the pound than it does in a flat-rate box. Both numbers matter before you pick a service.
First-Class Package International Service tops out at 4 lb. Priority Mail International and Priority Mail Express International both run to 66 lb for the United Kingdom, and both price this lane on the same Group 20 weight table.
| Weight not over | First-Class Package International Service | Priority Mail International | Priority Mail Express International |
|---|---|---|---|
| 8 oz | $23.05 | — | — |
| 1 lb | $31.95 | $69.70 | $93.15 |
| 2 lb | $35.70 | — | — |
| 3 lb | $49.25 | — | — |
| 4 lb (First-Class ceiling) | $64.25 | $88.45 | $108.10 |
| 5 lb | not offered past 4 lb | $94.45 | $113.55 |
| 10 lb | not offered past 4 lb | $118.40 | $141.60 |
| 20 lb | not offered past 4 lb | $177.50 | $197.25 |
First-Class Package International Service is the cheapest way to reach London under 4 lb, and it stays cheaper than Priority Mail International priced by weight at every point on this table. Past 4 lb it stops being an option at all, and the choice narrows to Priority Mail International against its faster, pricier sibling.
The same Notice 123 price list puts the United Kingdom in Price Group 5 for flat-rate boxes and envelopes — a much cheaper group than the 20 it draws for weight-based pricing. A heavy item packed into a small, fixed-size USPS box can cost a fraction of the pound-by-pound rate.
| Container | Weight ceiling | Price |
|---|---|---|
| Priority Mail International Flat Rate Envelope | 4 lb | $52.30 |
| Priority Mail International Small Flat Rate Box | 4 lb | $54.00 |
| Priority Mail International Medium Flat Rate Box | 20 lb | $95.95 |
| Priority Mail International Large Flat Rate Box | 20 lb | $108.85 |
| Priority Mail Express International Flat Rate Envelope | 4 lb | $87.10 |
Set the Large Flat Rate Box against the weight table above: $108.85 for up to 20 lb, next to $177.50 for the same 20 lb priced by the pound. The gap only closes if the item is too big for the box, since none of these prices bend for a lighter parcel — a flat rate is exactly that.
Picking a service by its weight ceiling, rather than by name, is where the savings sit. Two examples pulled straight from the tables above show it at both ends of the scale.
First-Class Package International Service: $64.25. Priority Mail International priced by weight: $88.45. Priority Mail International Small Flat Rate Box, if the contents fit: $54.00 — cheaper than either, because it draws Group 5 instead of Group 20.
Priority Mail International priced by weight: $177.50. Priority Mail Express International priced by weight: $197.25. Priority Mail International Large Flat Rate Box, if it fits: $108.85 — well under the weight-based price two columns over for the identical 20 lb.
Flat-rate pricing only holds if the item physically fits inside USPS's own box or envelope. A carton that needs its own dimensions goes on the weight-based table instead, whatever the pound-for-pound math says.
USPS publishes a rate a shopper can read straight off the page. UPS and FedEx do not, on this lane or any other international one.
UPS's own international resources page, read 2026-08-30, names UPS Worldwide Economy as “a budget-friendly solution” and states no delivery-time commitment for a US-to-UK shipment on that page. It prints no per-pound rate chart; UPS routes pricing through its own Calculate Time and Cost tool, which needs an account and an actual shipment to return a number. FedEx's international shipping pages returned a server error when checked the same day, so nothing about FedEx's ladder is stated here that was not read live — get a number from FedEx's own rate tool instead of a description written before today.
That is the practical reason USPS carries this whole page: it is the one of the three carriers that prints a weight-and-country rate table anyone can read without logging in first.
USPS lists the United Kingdom at Price Group 3 with a $2,499 declared-value ceiling for Global Express Guaranteed, but the whole product has been suspended since September 29, 2024, and nothing on USPS's site says when it returns. Price never enters into it — it simply cannot be bought right now.
USPS states plainly that insurance is not available on Priority Mail International to the United Kingdom, on the flat-rate boxes or the weight-based service. A cracked collectible mailed on the cheapest ladder above has no coverage behind it at all.
Priority Mail Express International does cover merchandise loss on this lane, unlike its cheaper sibling. What it does not carry to Great Britain is the money-back promise: USPS suspended it on October 25, 2021, alongside Israel, New Zealand, Singapore, Sweden and Switzerland, and the suspension still stands.
Nothing above includes what lands on the recipient once the parcel clears UK customs. gov.uk sets separate duty and VAT thresholds in pounds sterling, and the postage figures above feed straight into that VAT base — the full breakdown, with the size and blade rules for this lane, is on our UK shipping rules page.
USPS revises Notice 123 without much notice, and price groups have moved before. Everything above reflects Notice 123 as it stood on 2026-08-30; a shipment planned for later deserves a fresh reading of the same page.
USPS prices a parcel to the United Kingdom on Price Group 20 for its weight-based services: $69.70 to $177.50 for Priority Mail International and $93.15 to $197.25 for Priority Mail Express International, at 1 to 20 lb. First-Class Package International Service runs $23.05 to $64.25 under its 4 lb ceiling. All figures are from Notice 123, effective July 12, 2026, read 2026-08-30.
Often, yes. The United Kingdom sits in the cheaper Price Group 5 for Priority Mail International flat-rate boxes and envelopes, while its weight-based price runs on the pricier Group 20. A Large Flat Rate Box holding up to 20 lb costs $108.85 against $177.50 for the same weight priced by the pound, as long as the contents actually fit the box.
No. USPS lists the United Kingdom at Price Group 3 with a $2,499 declared-value ceiling for Global Express Guaranteed, but the service itself has been suspended since September 29, 2024, with no restoration date published. It is not purchasable at any price on this lane right now.
No. USPS states plainly that insurance is not available on Priority Mail International shipments to the United Kingdom, on the flat-rate boxes or the weight-based service. Priority Mail Express International does offer insurance for merchandise on this lane, which is one reason to pay its higher price.
Not right now. USPS suspended the money-back guarantee on Priority Mail Express International to Great Britain on October 25, 2021, alongside Israel, New Zealand, Singapore, Sweden and Switzerland, and the suspension is still standing. The 3 to 5 business day estimate still applies; only the refund-if-late part is gone.