The UK prices worse by the pound than it does in a flat-rate box. Both numbers matter before you pick a service.
Priced by the pound: Price Group 20
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.
Where a flat-rate box beats paying by weight
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.
Two cartons, priced every way USPS sells them
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.
A 4 lb padded mailer
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.
A 20 lb carton
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.
What decides which one you can use
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.
What UPS and FedEx charge for the same box
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; the way to see courier numbers for your exact box is a live quote, which our own UK checkout returns in under a minute.
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.
Three things that change which service you'd buy
Global Express Guaranteed is off the table
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.
Priority Mail International carries no protection
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.
The faster service's clock has no teeth here
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.
The bill that lands after the postage
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.
Where these numbers come from
- USPS Postal Explorer, Notice 123, Price List — every dollar figure on this page, the Price Group 20 and Price Group 5 rate tables, and the Country Price Groups table assigning the United Kingdom to each. Effective July 12, 2026, read 2026-08-30.
- USPS Postal Explorer, Individual Country Listing — United Kingdom of Great Britain and Northern Ireland — the Global Express Guaranteed price group, value ceiling and suspension, and the insurance availability language for Priority Mail International and Priority Mail Express International. Read 2026-08-30.
- USPS, International Service Alerts — the Priority Mail Express International money-back guarantee suspension to Great Britain, effective October 25, 2021. Read 2026-08-30.
- UPS, International Tools & Resources — the UPS Worldwide Economy description and the absence of a published per-pound rate chart. Read 2026-08-30.
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.
Shipping to the UK, answered
How much is shipping from the USA to the UK?
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.
Is a flat-rate box cheaper than paying by weight to the UK?
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.
Can I buy Global Express Guaranteed to the UK?
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.
Does Priority Mail International cover a lost package to the UK?
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.
Does the faster USPS service come with a delivery guarantee to the UK?
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.